{"id":9478,"date":"2026-06-25T14:17:31","date_gmt":"2026-06-25T06:17:31","guid":{"rendered":"https:\/\/www.flywing-tech.com\/blog\/?p=9478"},"modified":"2026-06-25T14:17:33","modified_gmt":"2026-06-25T06:17:33","slug":"cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples","status":"publish","type":"post","link":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/","title":{"rendered":"CD4017 Decade Counter IC: Pinout, Features &amp; LED Chaser Circuit Examples"},"content":{"rendered":"<div class=\"fsc_text\">\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_76 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\r\n<div class=\"ez-toc-title-container\">\r\n<h2 class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/h2>\r\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #023a85;color:#023a85\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #023a85;color:#023a85\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\r\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#what_is_the_cd4017_ic\" >What is the CD4017 IC?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#the_sequential_switching_problem\" >The Sequential Switching Problem<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#cd4017_electrical_specifications_and_cmos_characteristics\" >CD4017 Electrical Specifications and CMOS Characteristics<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#cd4017_pinout_every_pin_explained\" >CD4017 Pinout: Every Pin Explained<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#how_the_cd4017_works_internally_johnson_counter_and_decoder\" >How the CD4017 Works Internally: Johnson Counter and Decoder<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#building_a_cd4017_led_chaser_circuit_with_a_555_timer\" >Building a CD4017 LED Chaser Circuit with a 555 Timer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#advanced_cd4017_circuits_cascading_and_frequency_division\" >Advanced CD4017 Circuits: Cascading and Frequency Division<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#cd4017_vs_74hc4017_vs_arduino-based_counters\" >CD4017 vs. 74HC4017 vs. Arduino-Based Counters<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#troubleshooting_common_cd4017_problems\" >Troubleshooting Common CD4017 Problems<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#frequently_asked_questions\" >Frequently Asked Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#conclusion\" >Conclusion<\/a><\/li><\/ul><\/nav><\/div>\r\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"what_is_the_cd4017_ic\"><\/span><strong>What is the CD4017 IC?<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>CD4017 is a decade counter and <a href=\"https:\/\/www.flywing-tech.com\/search\/CD4017\">decoder IC<\/a> which has a 5-bit Johnson counter with decoding logic that can provide 10 sequential decoded outputs from the input clock signal. At a time, only one output is activated. On each rising clock edge, the active output shifts towards the next pin. After the 10th output, the IC resets itself and starts from the beginning again. No programming is required for its operation.<\/p>\n\n\n\n<div style=\"margin:40px auto;background:#ffffff;border-radius:12px;padding:20px;font-family:'Segoe UI',Roboto,Arial,sans-serif\" class=\"table-scrollable\">\n\n    <table style=\"width:100%;border-collapse:collapse;font-size:14px;min-width:900px\">\n\n        <thead style=\"background:linear-gradient(135deg,#065f46,#10b981);color:#ffffff\">\n            <tr>\n                <th style=\"padding:12px;border:1px solid #047857\">Parameter<\/th>\n                <th style=\"padding:12px;border:1px solid #047857\">Value \/ Range<\/th>\n            <\/tr>\n        <\/thead>\n\n        <tbody>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Supply Voltage (VDD)<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">3 V to 15 V (some variants to 18 V)<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Logic Family<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">CMOS (4000B series)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Counter Type<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">5-stage Johnson counter with decoder<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Number of Outputs<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">10 decoded outputs (Q0\u2013Q9)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Max Clock Frequency<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Up to 10 MHz (voltage dependent)<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Propagation Delay<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">~100 ns at 15 V (slower at lower VDD)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Static Current Draw<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Microwatt range (typ. &lt; 1 \u00b5A static)<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Clock Input Type<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Schmitt-triggered (built-in pulse shaping)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Reset Pin Logic<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Active-HIGH<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Clock Enable Logic<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Active-HIGH inhibit (LOW = counting enabled)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Carry Out Function<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Goes HIGH for 5 of every 10 clock cycles<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Package Options<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">16-pin PDIP, SOIC-16<\/td>\n            <\/tr>\n\n            <tr style=\"background:#ecfdf5\">\n                <td style=\"padding:12px;border:1px solid #d1fae5;font-weight:600\">Output Drive<\/td>\n                <td style=\"padding:12px;border:1px solid #d1fae5\">Each output can directly drive an LED with resistor<\/td>\n            <\/tr>\n\n        <\/tbody>\n\n    <\/table>\n\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"the_sequential_switching_problem\"><\/span><strong>The Sequential Switching Problem<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>You want to have LED lights sequentially illuminated, with just one LED turned on at a time, and then cycle through them. The most common way to do this is to use some other type of binary counter like a <a href=\"https:\/\/www.flywing-tech.com\/search\/CD4040\">CD4040<\/a> or a microcontroller pin. A binary counter counts in binary (0000, 0001, 0010, 0011). To take that binary count and generate ten outputs with only one at a time having a HIGH output you will need a decoder. When you use a decoder it will add additional complexity with extra gates, wires, and possible issues on a breadboard.<\/p>\n\n\n\n<p>One of the most common ways to do this is with the <a href=\"https:\/\/www.flywing-tech.com\/search\/CD4017\">CD4017 Counter<\/a>. Instead of doing the counting and then the decoding separately, the CD4017 does both counting and decoding all inside of one chip. To use this chip all you have to do is send it a clock pulse, you will get a HIGH output on one of its ten outputs. So you do not need any additional decoder logic or programming; you just need one IC, and a clock signal to drive an LED, relay, or transistor switch directly to ten outputs.<\/p>\n\n\n\n<p>The CD4017 decade counter has truly developed into a commonly used part for hobbyists that do electronics, for schools and laboratories for teaching electronics, and for simple automation circuits as it is a simple design decision to use it and allows you to perform its intended operation without complication or other supporting circuitry.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/CD4017-Functional-Block-Diagram.png\" alt=\"CD4017 decade counter functional block diagram with 5-stage Johnson counter, decoder network, clock input, reset, and Q0\u2013Q9 sequential outputs.\" class=\"wp-image-9481\" \/><\/figure>\n\n\n\n<p>The CD4017 decade counter is part of the CMOS <a href=\"https:\/\/share.google\/KZP8yrFSQvEE5JDJV\">4000 series<\/a> logic family, which comprises a set of ICs standardised in the 1970s and still being manufactured. The <a href=\"https:\/\/www.flywing-tech.com\/search\/CD4017B\">CD4017B<\/a> is being manufactured by<a href=\"https:\/\/www.flywing-tech.com\/manufacturers\/texas-instruments\"> Texas Instruments<\/a>. Some other manufacturers also manufacture variants of this family with other prefixes in Section 8.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"cd4017_electrical_specifications_and_cmos_characteristics\"><\/span><strong>CD4017 Electrical Specifications and CMOS Characteristics<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>These values represent the standard CD4017B IC as per the specifications of Texas Instruments and the general CMOS <a href=\"https:\/\/share.google\/KZP8yrFSQvEE5JDJV\">4000B series<\/a>. Always double-check the actual values from your <a href=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/cd4022b.pdf\">datasheet<\/a> as per the manufacturer of the chip and its package.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Supply Voltage Range<\/strong><\/h3>\n\n\n\n<p>The CD4017 decade counter operates from 3V to 15V. Some manufacturer versions of this IC increase the upper value limit to 18V. One of the main advantages of using CMOS 4000-series logic as opposed to modern families of logic ICs is the versatility of this IC, which allows operating from a battery cell, 9V battery, or regulated 12V power supply without any change in circuit design.<\/p>\n\n\n\n<p>Higher supply voltage increases switching speed and noise immunity, but increases power consumption while switching. Hobbyist LED chaser projects mostly use 9V or 12V supplies that provide sufficient noise immunity and adequate driving capability for LEDs.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Maximum Clock Frequency<\/strong><\/h3>\n\n\n\n<p>The maximum clock frequency of CD4017 is around 10 MHz, but this depends on the voltage level used. The propagation delay time in the circuit decreases with an increase in VDD \u2014 100 ns at 15 V and higher for lower voltages. In most of the LED chaser or sequencer projects, the actual clock frequency lies in the range of 0.5 Hz and 20 Hz, which is way below the mentioned ceiling value.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Static Current Draw<\/strong><\/h3>\n\n\n\n<p>CMOS circuits consume power only when there is a state change; otherwise, very little power consumption occurs during static operation. The static current drain in CD4017 decade counter falls in the microwatt region. Thus, CD4017 is ideal for battery-operated projects that can operate for a long period of time \u2014 the power consumed by the novelty light using battery cells will be more due to LEDs than due to CD4017.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Schmitt-Triggered Clock Input<\/strong><\/h3>\n\n\n\n<p>The input for the clock pulse contains the built-in Schmitt trigger for pulse shaping. This implies that the input has a hysteretic behavior and it does not change state unless the signal crosses a certain threshold. The advantage of this is that you can provide a clock signal to the CD4017 that has poor rise and fall characteristics, such as the one produced by an RC oscillator circuit.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"cd4017_pinout_every_pin_explained\"><\/span><strong>CD4017 Pinout: Every Pin Explained<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The CD4017 ships in a 16-pin package. The PDIP-16 (Plastic Dual In-line Package) is the breadboard-friendly version most hobbyists use. The SOIC-16 surface-mount version is identical electrically but suited to compact PCB designs.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/LoRa-loT-ecosystem-based-on-the-SX1276-transceiver-3.png\" alt=\"CD4017 pinout diagram with labeled clock, reset, carry out, VDD, VSS, and Q0\u2013Q9 output pins.\" class=\"wp-image-9482\" \/><\/figure>\n\n\n\n<div style=\"margin:40px auto;background:#ffffff;border-radius:12px;padding:20px;font-family:'Segoe UI',Roboto,Arial,sans-serif\" class=\"table-scrollable\">\n\n    <table style=\"width:100%;border-collapse:collapse;font-size:14px;min-width:950px\">\n\n        <thead style=\"background:linear-gradient(135deg,#6d28d9,#a855f7);color:#ffffff\">\n            <tr>\n                <th style=\"padding:12px;border:1px solid #7e22ce\">Pin<\/th>\n                <th style=\"padding:12px;border:1px solid #7e22ce\">Name<\/th>\n                <th style=\"padding:12px;border:1px solid #7e22ce\">Function<\/th>\n            <\/tr>\n        <\/thead>\n\n        <tbody>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">1<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">GND<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Ground \u2014 system reference (note: some sources label pin 8 as GND; verify against your specific datasheet revision)<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">2<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q5<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 5 \u2014 goes HIGH on the 6th clock pulse<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">3<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q0<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 0 \u2014 first output, HIGH at startup\/reset<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">4<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q1<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 1 \u2014 HIGH on the 2nd clock pulse<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">5<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q2<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 2 \u2014 HIGH on the 3rd clock pulse<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">6<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q6<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 6 \u2014 HIGH on the 7th clock pulse<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">7<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q7<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 7 \u2014 HIGH on the 8th clock pulse<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">8<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">GND \/ VSS<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Ground connection \u2014 negative supply reference<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">9<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q8<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 8 \u2014 HIGH on the 9th clock pulse<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">10<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q4<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 4 \u2014 HIGH on the 5th clock pulse<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">11<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">Q9<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Decoded output 9 \u2014 HIGH on the 10th clock pulse<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">12<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">CO<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Carry Out \u2014 goes HIGH after every 10 clock pulses, used for cascading<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">13<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">CE<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Clock Enable \u2014 active-HIGH inhibit; tie LOW for normal counting<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">14<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">CLK<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Clock input \u2014 Schmitt-triggered, advances count on rising edge<\/td>\n            <\/tr>\n\n            <tr style=\"background:#faf5ff\">\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">15<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">MR \/ RESET<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Master Reset \u2014 active-HIGH; forces counter back to Q0<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">16<\/td>\n                <td style=\"padding:12px;font-weight:600;border:1px solid #e9d5ff\">VDD<\/td>\n                <td style=\"padding:12px;border:1px solid #e9d5ff\">Positive supply voltage (3 V to 15 V)<\/td>\n            <\/tr>\n\n        <\/tbody>\n\n    <\/table>\n\n<\/div>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/www.flywing-tech.com\/product-detail\/logic-counters-dividers-texas-instruments-cd4017be-c883c0e4\" target=\"_blank\" rel=\" noreferrer noopener\"><img loading=\"lazy\" decoding=\"async\" width=\"2160\" height=\"270\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/cd4017be.png\" alt=\"Texas Instruments CD4017BE decade counter IC \u2013 10-bit 16-PDIP counter specifications and technical support at Flywing\" class=\"wp-image-9520\" \/><\/a><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>The Non-Sequential Output Layout \u2014 A Common Source of Wiring Mistakes<\/strong><\/h3>\n\n\n\n<p>One thing that surprises many new builders about the IC packaging is that the output pins are not ordered in sequentially numbered around the package. Although pin 3 has Q0, 2 has Q1, and 4 has Q2, there is no sequential numbering because of the way the internal Johnson counter and Decoder Logic route to the physical connections.&nbsp;<\/p>\n\n\n\n<p>This is not an error in documentation; it was the way the chip was designed, and all legitimate <a href=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/cd4022b.pdf\">datasheets <\/a>will show the same non-sequential mapping for output pins. The solution is to always wire by output function (Q0, Q1, Q2&#8230;) using the pin reference table, and do not assume the pin labels increase sequentially around the package.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Clock Input and Clock Enable<\/strong><\/h3>\n\n\n\n<p>Pin 14 is the Clock input; it produces a rising edge output on the rising edge of the clock signal from LOW to HIGH; therefore, each rising edge of the Clock signal advances the Count by one count. The Clock Enable pin (Pin 13) will only count the Clock signal in these two states (HIGH means it will count), and when it is an active LOW, it will ignore all clock signals and hold its state. To allow for normal continuous counting, connect the Clock Enable to the ground.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Reset and Carry Out<\/strong><\/h3>\n\n\n\n<p>Pin 15 is Master Reset; also denoted as MR; when the Master Reset pin is pulled to a HIGH, the counter will be forced to Q0. This occurs regardless of the clock&#8217;s state. For normal operation, connect the M Reset to the Ground. Pin 12 is the Carry-Out (CO); the CO pin will be HIGH during the second half of every 10 counts (5-9) and will be LOW during the first half. The CO pin of the counter completes one full cycle (HIGH and LOW) during the 10 clocks, i.e., it is the correct signal to cascade to the second CD4017.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"how_the_cd4017_works_internally_johnson_counter_and_decoder\"><\/span><strong>How the CD4017 Works Internally: Johnson Counter and Decoder<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"What is CD4017 IC | How to use CD4017 IC\" width=\"1778\" height=\"1000\" src=\"https:\/\/www.youtube.com\/embed\/WIIcYPLMbgM?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>Understanding the internal logic removes the mystery and makes every external wiring decision make sense.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>The Johnson Counter Core<\/strong><\/h3>\n\n\n\n<p>The core of the CD4017 is a chain of five D-type flip flops in the form of a ring, which is also known as the Johnson counter (switch-tail ring counter). The output from one flip-flop is fed to the next, with the inverted output of the fifth flip-flop returned to the first flip flop. A Johnson counter has 10 unique internal states for every 10 pulses applied to its input, despite having five flip flops.<\/p>\n\n\n\n<p>A typical chain of five flip flops can generate 32 different binary states (2^5). But in the case of the Johnson counter, out of the total 32 states only 10 states are utilized. It has been done intentionally because of the sequence in which the states are generated. Such a sequence makes it possible to generate a very simple decoder for the 10 states.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>The Decoder Stage: Converting Internal States to One-Hot Outputs<\/strong><\/h3>\n\n\n\n<p>The decoder circuitry, made up of a combination of inverters and logic gates, checks the five flip-flop statuses and ensures that only one of the ten Q outputs is on at a time. In this case, we say there is one-hot encoding because only one output is on (HIGH) at a time, while all other output lines remain off (LOW).<\/p>\n\n\n\n<p>The above scenario is completely different from a binary counter. For example, a 4-bit binary counter has the number 5 encoded as 0101; that is, two output lines are HIGH while two are LOW. This requires additional decoding to have one indicator line. However, in CD4017, 5 is represented when the pin Q5 goes HIGH.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Count Sequence and Rollover<\/strong><\/h3>\n\n\n\n<p>The typical start-up condition of the CD4017 is that the output Q0 will be HIGH when the device powers up (even though this is not always true; it may sometimes require an initial reset pulse to assure this start-up condition), and on each successive positive-going clock pulse, the HIGH output shifts to the next pin in order: Q0 -&gt; Q1 -&gt; Q2 -&gt; &#8230; -&gt; Q9. Once Q9 has become HIGH and another clock pulse occurs, the device resets back to Q0, and the process begins again.<\/p>\n\n\n\n<div style=\"margin:40px 0;padding:18px 20px;border-radius:12px;font-family:'Segoe UI',Roboto,Arial,sans-serif;background:#18181b;border:1px solid #ef4444;border-left:6px solid #dc2626;color:#f8fafc\">\n\n    <div style=\"font-size:16px;line-height:1.7\">\n\n        <div style=\"font-size:17px;font-weight:700;color:#f87171;margin-bottom:12px\">\n            Key Technical Point \u2014 Clock Signal Quality Matters\n        <\/div>\n\n        <div>\n            The CD4017 advances its count on every rising edge it detects. A noisy or bouncing clock signal \u2014 common with mechanical push-button inputs without debouncing, or poorly filtered oscillator circuits \u2014 can produce multiple unwanted rising edges from what should be a single clean pulse. This causes the counter to skip ahead unpredictably.\n            \n            <br><br>\n\n            Always use a clean oscillator source (like a 555 timer) or proper hardware\/software debouncing for switch-based clock inputs.\n        <\/div>\n\n    <\/div>\n\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"building_a_cd4017_led_chaser_circuit_with_a_555_timer\"><\/span><strong>Building a CD4017 LED Chaser Circuit with a 555 Timer<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>This is the canonical CD4017 project, and for good reason. It demonstrates every core concept of the chip in a circuit you can build on a breadboard in under twenty minutes.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Why Pair the CD4017 with a 555 Timer<\/strong><\/h3>\n\n\n\n<p>In order for the CD4017 to count correctly, it will require an external source of clock pulses (due to the lack of a built-in clock generator). The easiest and most reliable method of generating that clock pulse is by using a 555 timer configured in the &#8220;astable&#8221; mode. This configuration will produce a continuous square wave with a frequency that is determined by two resistors and a capacitor that can be easily calculated and adjusted, but will still tolerate any wiring imperfections associated with using a breadboard.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Component List<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>CD4017 decade counter IC (16-pin DIP)<\/li>\n\n\n\n<li><a href=\"https:\/\/www.flywing-tech.com\/search\/NE555\">NE555<\/a> timer IC (8-pin DIP)<\/li>\n\n\n\n<li>10 LEDs (any color, standard 5mm)<\/li>\n\n\n\n<li>10 \u00d7 220\u03a9 resistors (current limiting \u2014 one per LED)<\/li>\n\n\n\n<li>R1: 10k\u03a9 resistor (555 timing)<\/li>\n\n\n\n<li>RV1: 50k\u03a9 potentiometer (555 timing \u2014 speed control)<\/li>\n\n\n\n<li>C1: 10\u00b5F capacitor (555 timing)<\/li>\n\n\n\n<li>C2: 0.01\u00b5F capacitor (555 control voltage filtering, pin 5)<\/li>\n\n\n\n<li>0.1\u00b5F decoupling capacitors \u00d7 2 (one near each IC&#8217;s power pins)<\/li>\n\n\n\n<li>9V battery or regulated power supply<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Wiring the 555 Timer (Astable Mode)<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pin 8 (VCC)<\/strong> \u2192 positive supply rail<\/li>\n\n\n\n<li><strong>Pin 1 (GND)<\/strong> \u2192 ground rail<\/li>\n\n\n\n<li><strong>Pin 4 (Reset)<\/strong> \u2192 tied directly to VCC (prevents accidental reset)<\/li>\n\n\n\n<li><strong>Pin 5 (Control Voltage)<\/strong> \u2192 0.01\u00b5F capacitor to ground (noise filtering, not used for control here)<\/li>\n\n\n\n<li><strong>Pins 6 and 7<\/strong> \u2192 connected together, through R1 and RV1 in series to VCC<\/li>\n\n\n\n<li><strong>Pin 2<\/strong> \u2192 connected to the junction of pins 6\/7 (discharge path) and to C1, which connects to ground<\/li>\n\n\n\n<li><strong>Pin 3 (Output)<\/strong> \u2192 this is the clock signal \u2014 connect to CD4017 pin 14<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Wiring the CD4017<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pin 16 (VDD)<\/strong> \u2192 positive supply rail<\/li>\n\n\n\n<li><strong>Pin 8 (GND)<\/strong> \u2192 ground rail<\/li>\n\n\n\n<li><strong>Pin 14 (CLK)<\/strong> \u2192 555 timer pin 3 (clock signal in)<\/li>\n\n\n\n<li><strong>Pin 13 (CE)<\/strong> \u2192 ground (enables continuous counting)<\/li>\n\n\n\n<li><strong>Pin 15 (MR\/Reset)<\/strong> \u2192 ground (disables reset, allows free counting)<\/li>\n\n\n\n<li><strong>Pins for Q0\u2013Q9<\/strong> \u2192 each through its own 220\u03a9 resistor to the anode of an LED; LED cathodes to ground<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/LoRa-loT-ecosystem-based-on-the-SX1276-transceiver-4-1.png\" alt=\"LED chaser circuit using 555 timer and CD4017 decade counter with ten sequential LED outputs.\" class=\"wp-image-9483\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Adjusting Chase Speed<\/strong><\/h3>\n\n\n\n<p>The 555 timer&#8217;s oscillation frequency is determined by a potentiometer (RV1). This will directly influence how quickly the LED light sequence changes. With the maximum resistance (approximately 50k), the oscillation is approximately 0.7Hz (slow). With RV1 at the minimum resistance (approximately 1k), the oscillation is running at around 7Hz (quick and blurry). At 25k, the oscillation is approximately 1.4Hz, which should be suitable for a majority of decorative uses.<\/p>\n\n\n\n<p>The working principle is simple: as resistance decreases, the time for C1 to charge and discharge is reduced, which increases the frequency of oscillation and therefore the rate at which the LEDs will change. If you know how fast you want the LEDs to &#8220;chase,&#8221; you can calculate the 555 astable frequency formula first, then choose the component values to give you the desired output.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"advanced_cd4017_circuits_cascading_and_frequency_division\"><\/span><strong>Advanced CD4017 Circuits: Cascading and Frequency Division<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>6.1 Cascading Multiple CD4017 ICs<\/strong><\/h3>\n\n\n\n<p>If more than ten outputs are required, for example, twenty LEDs chasing in sequence, you can use two CD4017 chips in cascade. To do this, connect the Carry Out pin of the first chip (pin 12) to the Clock In pin of the second chip (pin 14). The first chip will count normally through its Q0 to Q9 outputs, but every time there is a complete cycle of ten counts in the first chip, the Carry Out pin will transition high, creating one clock pulse for the second chip.&nbsp;<\/p>\n\n\n\n<p>As a result, every time the first chip has completed a ten-count cycle, the second chip moves to the next LED. By connecting all the outputs of both chips to sequentially lit LEDs, you will have a cascading chase with twenty LEDs. You can continue this pattern for thirty, forty, or even more outputs by connecting additional CD4017s using the above process.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/LoRa-loT-ecosystem-based-on-the-SX1276-transceiver-5.png\" alt=\"CD4017 cascade counter circuit diagram with two-stage decade counter configuration for 0\u201399 counting.\" class=\"wp-image-9485\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Divide-by-N Frequency Division<\/strong><\/h3>\n\n\n\n<p>The CD4017 also works as a programmable frequency divider for all integers from 2 to 9. You can do this by connecting the reset pin (pin 15) to the output pin that is associated with the integer you want to divide by.<\/p>\n\n\n\n<p>As an example, if you wanted to create a divide-by-9 circuit, you would connect Q9 (the 10th output; pin 11) to the reset pin (pin 15). As the counter counts through Q0 \u2013 Q8, when Q9 would normally go low, it instead goes low, immediately resetting the counter back to Q0. Therefore, the total number of counts is 9 instead of 10; you have divided the frequency of the incoming clock signal by 9.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Divide by 2:<\/strong> connect Q2 (pin 4) to Reset \u2014 counter cycles through Q0, Q1 only<\/li>\n\n\n\n<li><strong>Divide by 5:<\/strong> connect Q5 (pin 2) to Reset \u2014 counter cycles through Q0\u2013Q4<\/li>\n\n\n\n<li><strong>Divide by 7:<\/strong> connect Q7 (pin 7) to Reset \u2014 counter cycles through Q0\u2013Q6<\/li>\n\n\n\n<li><strong>Divide by 9:<\/strong> connect Q9 (pin 11) to Reset \u2014 counter cycles through Q0\u2013Q8<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Noise Immunity on Control Pins<\/strong><\/h3>\n\n\n\n<p>Reset and Clock Enable lines are CMOS high-impedance inputs. If left floating (not connected), these lines become very prone to picking up electrical noise from surrounding switching circuits or even the ambient fluorescent lights. A floating Reset line may randomly go active, resetting your counter at some random point during the sequence.<\/p>\n\n\n\n<p>The fix:&nbsp; Always keep Reset and Clock Enable lines tied down. If the line must be LOW when your circuit is operating normally, tie it to ground; otherwise, pull it down using a resistor (commonly 10 kilo-ohms) if the line should sometimes be HIGH due to some other part of the circuit.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"cd4017_vs_74hc4017_vs_arduino-based_counters\"><\/span><strong>CD4017 vs. 74HC4017 vs. Arduino-Based Counters<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The CD4017 is not the only way to build a sequential output circuit. Choosing between it and the alternatives depends on your speed requirements, power budget, and how much flexibility your project needs.<\/p>\n\n\n\n<div style=\"margin:40px auto;background:#ffffff;border-radius:12px;padding:20px;font-family:'Segoe UI',Roboto,Arial,sans-serif\" class=\"table-scrollable\">\n\n    <table style=\"width:100%;border-collapse:collapse;font-size:14px;min-width:1000px\">\n\n        <thead style=\"background:linear-gradient(135deg,#c2410c,#f97316);color:#ffffff\">\n            <tr>\n                <th style=\"padding:12px;border:1px solid #ea580c\">Parameter<\/th>\n                <th style=\"padding:12px;border:1px solid #ea580c\">CD4017<\/th>\n                <th style=\"padding:12px;border:1px solid #ea580c\">74HC4017<\/th>\n                <th style=\"padding:12px;border:1px solid #ea580c\">HEF4017<\/th>\n                <th style=\"padding:12px;border:1px solid #ea580c\">Arduino-based<\/th>\n            <\/tr>\n        <\/thead>\n\n        <tbody>\n\n            <tr style=\"background:#fff7ed\">\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Logic Family<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">CMOS (4000B)<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">HCMOS<\/td>\n                <td style=\"padding:12px;border:1 solid #fed7aa\">CMOS<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Microcontroller<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Voltage Range<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">3\u201315 V<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">2\u20136 V<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">3\u201315 V (to 18V)<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">5 V (typical board)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#fff7ed\">\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Max Frequency<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">~10 MHz<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">~50 MHz<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">~12 MHz<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Software-limited<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Static Power<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Microwatt<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Microwatt<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Microwatt<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Milliwatt+ (MCU active)<\/td>\n            <\/tr>\n\n            <tr style=\"background:#fff7ed\">\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Pattern Flexibility<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Fixed sequence<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Fixed sequence<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Fixed sequence<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Fully programmable<\/td>\n            <\/tr>\n\n            <tr>\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Component Count<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Low (IC + clock)<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Low (IC + clock)<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Low (IC + clock)<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">MCU + code, fewer discretes<\/td>\n            <\/tr>\n\n            <tr style=\"background:#fff7ed\">\n                <td style=\"padding:12px;border:1px solid #fed7aa;font-weight:600\">Best For<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Simple hobby\/edu circuits<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Faster digital systems<\/td>\n                <td style=\"padding:12px;border:1 solid #fed7aa\">Industrial wide-voltage<\/td>\n                <td style=\"padding:12px;border:1px solid #fed7aa\">Custom or complex patterns<\/td>\n            <\/tr>\n\n        <\/tbody>\n\n    <\/table>\n\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>CD4017 vs. 74HC4017: Logic Family Differences<\/strong><\/h3>\n\n\n\n<p>The <a href=\"https:\/\/www.flywing-tech.com\/search\/74HC4017\">74HC4017<\/a> is identical to CD4017 in terms of pinout and counting functions, but it is made in HCMOS (High Speed CMOS) technology and not the 4000B series CMOS technology. The key differences: 74HC4017 operates in a narrower range of operating voltage (about 2-6 volts, better suited for modern 3.3v\/5v systems) but reaches much higher max frequency \u2014 typically about 50 MHz, as opposed to 10 MHz in the case of CD4017.<\/p>\n\n\n\n<p>As far as LED chaser and other timing circuit projects go, this difference does not matter in practice \u2014 both ICs work at frequencies that are orders of magnitude higher than those used in these circuits. CD4017 offers better flexibility in battery-operated projects due to a wider input voltage range.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>When a Microcontroller Makes More Sense<\/strong><\/h3>\n\n\n\n<p>An Arduino or similar microcontroller can replicate the CD4017&#8217;s sequencing behavior in a handful of lines of code, driving any number of outputs in any custom pattern \u2014 not just a fixed one-direction sequence. If your project needs the chase to reverse direction, skip outputs in a non-sequential pattern, or respond to sensor input, a microcontroller offers far more flexibility than hardware logic ever could.<\/p>\n\n\n\n<p>The trade-off is complexity and cost. A CD4017 plus a 555 timer costs less than a dollar in components and requires no code. An Arduino Uno costs significantly more and requires writing, uploading, and debugging firmware. For a fixed, simple, one-direction LED chase, the CD4017 approach remains genuinely simpler \u2014 not just nostalgic.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Equivalent and Pin-Compatible Parts<\/strong><\/h3>\n\n\n\n<p>Different manufacturers produce the same functional part (with different names). The functionality and pinout configuration of the <a href=\"https:\/\/www.flywing-tech.com\/search\/HEF4017\">HEF4017<\/a> (from NXP\/Philips), <a href=\"https:\/\/www.flywing-tech.com\/search\/MC14017\">MC14017<\/a> (from Motorola\/ON Semiconductor), and CD4017 are identical; however, the electrical specifications (Input Voltage Range &amp; Max Frequency) may vary slightly between the various manufacturers, so you must check the manufacturer&#8217;s specific <a href=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/cd4022b.pdf\">datasheet<\/a> for the exact voltage range and maximum frequency before substituting any of these components.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"troubleshooting_common_cd4017_problems\"><\/span><strong>Troubleshooting Common CD4017 Problems<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>LEDs Not Chasing at All<\/strong><\/h3>\n\n\n\n<p>First, check if the Clock Enable pin (13) is accidentally high? If this happens, then the IC does not respond to any clock pulse and retains its present output. Make sure it is grounded. Second, check whether there is any clock pulse available at pin 14? Use a multimeter or LED indicator at the output of the 555 timer (pin 3) to confirm the same. Third, check whether the reset pin (15) is high and is holding the counter output at Q0?<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Random Flickering or Skipped Counts<\/strong><\/h3>\n\n\n\n<p>It indicates that there must be clock signal noise or fluctuation in the power supply. In order to resolve the problem, add 0.1\u00b5F decoupling capacitors between the VDD and GND pins of both the CD4017 and 555 timer, as close as possible to the IC pins. Transitions due to the switching noise in the power line, without proper decoupling, can trigger unwanted transitions in the clock line.<\/p>\n\n\n\n<p>If clock signals are triggered from the mechanical switch rather than the 555 timer, then the reason may be the switch bounce. It means that pressing of a single physical switch results in multiple transitions of the electrical signal because the contacts bounce back and forth a number of times. Thus, a debounce mechanism should be added to the clock line.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Speed Control Not Working<\/strong><\/h3>\n\n\n\n<p>In case there is no effect on the speed of chasing by turning the potentiometer, three items must be checked: the potentiometer is wired as a variable resistor in series with the 555 timing circuit (not wired as a voltage divider to feed an unrelated pin), the capacitor C1 in the 555 timing circuit is not open or shorted, and the potentiometer is not faulty.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Oscilloscope Verification<\/strong><\/h3>\n\n\n\n<p>First, use the probe to test pin 14 (Clock). When the probe touches pin 14, you should see a sharp-edged square wave output at the frequency you have established by adjusting the RC network of the 555 timer. If there is either rounding of the square wave or multiple fast transitions near the edges of the square wave, then you have a problem with noise or excessive loading due to the upstream devices connected to pin 14.<\/p>\n\n\n\n<p>Next, test the output pins from Q0 to Q9 in order, or if you are lucky enough to have a multi-channel oscilloscope, test all of the output pins at the same time by connecting each output pin to its dedicated channel. When testing the outputs, you should see a clean LOW-to-HIGH transition at the output pin for one clock cycle. After one clock cycle, the output should return to a LOW state so the next output pin can be driven HIGH. If any output stays HIGH for more than one clock cycle, or fails to drive HIGH, there is a problem with the wiring to that output pin.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/LoRa-loT-ecosystem-based-on-the-SX1276-transceiver-6.png\" alt=\"CD4017 decade counter IC oscilloscope verification waveforms showing clock input and sequential output transitions Q0\u2013Q3.\" class=\"wp-image-9486\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"frequently_asked_questions\"><\/span><strong>Frequently Asked Questions<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-1782141863433\"><strong class=\"schema-faq-question\"><strong>Q1: What does the CD4017 IC do?<\/strong><\/strong> <p class=\"schema-faq-answer\">The CD4017 is a CMOS decade counter and decoder IC that counts clock pulses from 0 to 9 and activates one output (Q0\u2013Q9) at a time in sequence. It is commonly used in LED chasers, sequencers, and frequency divider circuits.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1782141972375\"><strong class=\"schema-faq-question\"><strong>Q2: What is the maximum clock frequency for CD4017?<\/strong><\/strong> <p class=\"schema-faq-answer\">The CD4017 can operate at approximately 10 MHz, depending on the supply voltage. At lower voltages, the maximum frequency decreases, but this is rarely a limitation for LED chaser circuits, which typically run below 100 Hz.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1782141986966\"><strong class=\"schema-faq-question\"><strong>Q3: Can I cascade multiple CD4017 ICs?<\/strong><\/strong> <p class=\"schema-faq-answer\">Yes. Connect the Carry Out pin (12) of one CD4017 to the Clock input (14) of the next. Each additional IC adds 10 sequential outputs, allowing two ICs for 20 outputs, three for 30, and so on.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1782142008312\"><strong class=\"schema-faq-question\"><strong>Q4: How do I make CD4017 count to a number less than 10?<\/strong><\/strong> <p class=\"schema-faq-answer\">Connect the required output pin to the Reset pin (15). For example, connecting Q9 to Reset creates a divide-by-9 counter by resetting the IC before Q9 becomes active.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1782142025025\"><strong class=\"schema-faq-question\"><strong>Q5: What is the difference between CD4017 and 74HC4017?<\/strong><\/strong> <p class=\"schema-faq-answer\">Both ICs have the same pinout and counting function. The CD4017 uses standard CMOS technology with a wider voltage range (3\u201315 V), while the 74HC4017 uses HCMOS technology with a lower voltage range (2\u20136 V) and higher speed capability. Both are suitable for LED chaser projects.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1782142043157\"><strong class=\"schema-faq-question\"><strong>Q6: Why are my CD4017 outputs not in pin-number order?<\/strong><\/strong> <p class=\"schema-faq-answer\">This is normal. The output pins are not arranged sequentially on the package; for example, Q0 is pin 3, while Q1 is pin 2 and Q2 is pin 4. Always follow the output labels (Q0, Q1, etc.) rather than the physical pin order.<\/p> <\/div> <\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"conclusion\"><\/span><strong>Conclusion<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The CD4017 decade counter integrated circuit is one of the easiest and most effective ways to design sequential output circuits. This device combines a Johnson counter and decoder in a single package, allowing it to generate 10 sequential outputs from a clock signal without requiring additional decoding circuitry or programming. Its wide operating voltage range, low power consumption, and simple operation make it a popular choice for LED chasers, frequency dividers, educational projects, and basic automation systems.<\/p>\n\n\n\n<p>In this guide, we covered the CD4017 pinout, electrical specifications, internal Johnson counter architecture, working principle, LED chaser circuit design using a 555 timer, cascading techniques for additional outputs, frequency division applications, troubleshooting methods, and comparisons with alternative solutions such as the <a href=\"https:\/\/www.flywing-tech.com\/search\/74HC4017\">74HC4017<\/a> and Arduino-based counters.<\/p>\n\n\n\n<p>Whether you are building a simple LED chaser, expanding output channels with multiple <a href=\"https:\/\/www.flywing-tech.com\/search\/CD4017\">CD4017<\/a>s, or creating a reliable frequency divider, the CD4017 remains a cost-effective and dependable solution. By understanding its operation and design considerations, you can confidently use this versatile IC in a wide range of digital electronics projects.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/www.flywing-tech.com\/category\/integrated-circuits-ics\/logic-counters-dividers-e76ad29c\" target=\"_blank\" rel=\" noreferrer noopener\"><img loading=\"lazy\" decoding=\"async\" width=\"2160\" height=\"798\" src=\"https:\/\/www.flywing-tech.com\/blog\/wp-content\/uploads\/2026\/06\/counters-dividers-for-digital-timing-control.png\" alt=\"logic counter and divider ICs used for counting operations, frequency division, and timing control in digital electronic systems.\" class=\"wp-image-9521\" \/><\/a><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>What is the CD4017 IC? CD4017 is a decade counter and decoder IC which has a 5-bit Johnson counter with decoding logic that can provide 10 sequential decoded outputs from the input clock signal. At a time, only one output is activated. On each rising clock edge, the active output shifts towards the next pin. [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":9519,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1454,377,378],"tags":[603,1459,1455,1464,1461,1457,1463,485,658,1460,1458,1456,1462,1465],"class_list":["post-9478","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-digital-logic-hobby-projects","category-experience-sharing","category-parts-library","tag-555-timer","tag-cascading-counters","tag-cd4017","tag-cd4017be","tag-cmos-ic","tag-decade-counter","tag-digital-counter","tag-diy-electronics","tag-electronics-tutorial","tag-frequency-divider","tag-johnson-counter","tag-led-chaser-circuit","tag-pinout-diagram","tag-sequential-led-lights"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\r\n<title>CD4017 Decade Counter IC: Pinout, Features &amp; LED Chaser Circuit Examples - Fly-Wing<\/title>\r\n<meta name=\"description\" content=\"Master the CD4017 decade counter with this complete guide. 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It is commonly used in LED chasers, sequencers, and frequency divider circuits.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782141972375","position":2,"url":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782141972375","name":"Q2: What is the maximum clock frequency for CD4017?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"The CD4017 can operate at approximately 10 MHz, depending on the supply voltage. At lower voltages, the maximum frequency decreases, but this is rarely a limitation for LED chaser circuits, which typically run below 100 Hz.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782141986966","position":3,"url":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782141986966","name":"Q3: Can I cascade multiple CD4017 ICs?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Yes. Connect the Carry Out pin (12) of one CD4017 to the Clock input (14) of the next. Each additional IC adds 10 sequential outputs, allowing two ICs for 20 outputs, three for 30, and so on.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142008312","position":4,"url":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142008312","name":"Q4: How do I make CD4017 count to a number less than 10?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Connect the required output pin to the Reset pin (15). For example, connecting Q9 to Reset creates a divide-by-9 counter by resetting the IC before Q9 becomes active.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142025025","position":5,"url":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142025025","name":"Q5: What is the difference between CD4017 and 74HC4017?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Both ICs have the same pinout and counting function. The CD4017 uses standard CMOS technology with a wider voltage range (3\u201315 V), while the 74HC4017 uses HCMOS technology with a lower voltage range (2\u20136 V) and higher speed capability. Both are suitable for LED chaser projects.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142043157","position":6,"url":"https:\/\/www.flywing-tech.com\/blog\/cd4017-decade-counter-ic-pinout-features-led-chaser-circuit-examples\/#faq-question-1782142043157","name":"Q6: Why are my CD4017 outputs not in pin-number order?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"This is normal. The output pins are not arranged sequentially on the package; for example, Q0 is pin 3, while Q1 is pin 2 and Q2 is pin 4. 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