{"id":5083,"date":"2022-06-02T08:21:55","date_gmt":"2022-06-02T08:21:55","guid":{"rendered":"https:\/\/cnmegatech.com\/Axial-Fan\/?p=5083"},"modified":"2026-04-05T10:38:56","modified_gmt":"2026-04-05T10:38:56","slug":"3-pin-fan-vs-4-pin-fan","status":"publish","type":"post","link":"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/","title":{"rendered":"3 PIN FAN VS 4 PIN FAN"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\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: #999;color:#999\" 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: #999;color:#999\" 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>\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:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#Function_of_3_Pin_Fan_4_Pin_Fan\" >Function of 3 Pin Fan &amp; 4 Pin Fan<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#4_Pin_Fan\" >4 Pin Fan<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#PWM_CONTROL_SIGNAL\" >PWM CONTROL SIGNAL&nbsp;<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#PWM_CONTROL_LEAD_WIRE_INPUT_IMPEDANCE\" >PWM CONTROL LEAD WIRE INPUT IMPEDANCE<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#FG_and_RD_Function_Introduction\" >FG and RD Function Introduction<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/cnmegatech.com\/Axial-Fan\/3-pin-fan-vs-4-pin-fan\/#FG_Tach_output_type_Connection_Diagram\" >FG (Tach output type) Connection Diagram<\/a><\/li><\/ul><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Function_of_3_Pin_Fan_4_Pin_Fan\"><\/span><strong>Function of 3 Pin Fan &amp; 4 Pin Fan<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"has-medium-font-size\">Most cooling fans will connect to a PC with a standard connector of some sort. Modern systems will typically use&nbsp;<strong>3-pin or 4-pin dedicated fan headers<\/strong>, though standard MOLEX 4-pin peripheral connectors are also used. From left to right: A 3-pin connector, a 4-pin connector and a MOLEX connector.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"865\" height=\"251\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/connector-pictures-1.png\" alt=\"\" class=\"wp-image-5093\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/connector-pictures-1.png 865w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/connector-pictures-1-300x87.png 300w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/connector-pictures-1-768x223.png 768w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/connector-pictures-1-600x174.png 600w\" sizes=\"(max-width: 865px) 100vw, 865px\" \/><\/figure>\n\n\n\n<p style=\"font-size:24px\"><strong>3 Pin Fan<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\">The 3 pin fan connector has three indicators (as per the number of wires): The&nbsp;<strong>first wire<\/strong>&nbsp;is for power (4 to 12 volts),&nbsp;<strong>2nd<\/strong>&nbsp;is for ground and&nbsp;<strong>3rd wire<\/strong>&nbsp;is for a tachnometric signal (speed sensor) this sensor monitors the fan speed and performance.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">A tachnometric signal adjusts the level of power applied to the motor by transmitting the speed of rotation&nbsp;of the fan impeller at a nominal voltage between 5 to 12 volts.&nbsp;In this way, the fan speed is typically controlled by increasing or decreasing the voltage across the power cable.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Pinout&nbsp;<\/p>\n\n\n\n<p class=\"has-medium-font-size\"><strong>1 Ground<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\"><strong>2\u00a0+5V ~12V<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\"><strong>3 Tachometer<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-4-pin-fan\"><span class=\"ez-toc-section\" id=\"4_Pin_Fan\"><\/span><strong>4 Pin Fan<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"has-medium-font-size\">4 pin fan headers are commonly found in\u00a0modern motherboards. The 4 pin fan connector is slightly different from the 3 pin connector also works the same but the additional 4th wire is <a href=\"https:\/\/cnmegatech.com\/Axial-Fan\/how-pwm-dc-axial-fan-works\/\">PWM (<strong>Pulse Width Modulation<\/strong>)<\/a> used for controlling the power supply of the load and rotation speed of the fan impeller. <\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-2 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"525\" height=\"502\" data-id=\"5092\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/4PIN-CONNECTOR-1.png\" alt=\"\" class=\"wp-image-5092\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/4PIN-CONNECTOR-1.png 525w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/4PIN-CONNECTOR-1-300x287.png 300w\" sizes=\"(max-width: 525px) 100vw, 525px\" \/><\/figure>\n<\/figure>\n\n\n\n<p class=\"has-medium-font-size\">The duty cycle of the PWM signal controls the speed of the fan motor. The motor will be supplied with 12 V (for example )throughout, however, the duty cycle of the PWM signal decides how long the fan should be running or not. A duty cycle of 40% keeps the fan on for 40% of the total time period of the PWM signal, and the other 60% of the time it will remain off. The speed variation of cooling fans is within 30-100% of the rated speed, with the PWM technique and the minimum speed achieved by PWM fans being much lower than DC fans. The chassis and CPU temperature are the two factors that influence the speed of the cooling fans. The new technology advancements have brought firmware and software controlled PWM fans, where the speed is controlled according to the CPU or case temperature. The PWM fans are commonly seen as CPU coolers with higher power consumption.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"PWM_CONTROL_SIGNAL\"><\/span><strong>PWM <\/strong>CONTROL SIGNAL&nbsp;<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"354\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal-1024x354.png\" alt=\"\" class=\"wp-image-5085\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal-1024x354.png 1024w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal-300x104.png 300w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal-768x266.png 768w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal-600x208.png 600w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-control-signal.png 1130w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>\u25cfTHE FREQUENCY FOR CONTROL SIGNAL OF THE FAN SHALL BE ABLE TO ACCEPT 16K\uff5e32 KHZ.<br>\u25cf&nbsp; THE PREFERRED OPERATING POINT FOR THE FAN IS 25K HZ.<br>\u25cf&nbsp; AT 100% DUTY CYCLE,THE ROTOR WILL SPIN AT MAXIMUM SPEED.<br>\u25cf&nbsp; AT 0% DUTY CYCLE,THE ROTOR WILL STOP.<br>\u25cf&nbsp; WHEN CONTROL SIGNAL LEAD DISCINNECTED,THE FAN WILL MAXIMUM SPEED.<br>\u25cf&nbsp; AT 25K 3%\uff5e5% DUTY CYCLE,THE FAN WILL BE ABLE TO START FROM A DEAD STOP.<br>\u25cf&nbsp; THE FAN SPEED CONTROL IS CLOSED-LOOP.<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"PWM_CONTROL_LEAD_WIRE_INPUT_IMPEDANCE\"><\/span><strong>PWM <\/strong>CONTROL LEAD WIRE INPUT IMPEDANCE<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"948\" height=\"375\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-CONTROL-LEAD-WIRE-INPUT-IMPEDANCE.png\" alt=\"\" class=\"wp-image-5086\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-CONTROL-LEAD-WIRE-INPUT-IMPEDANCE.png 948w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-CONTROL-LEAD-WIRE-INPUT-IMPEDANCE-300x119.png 300w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-CONTROL-LEAD-WIRE-INPUT-IMPEDANCE-768x304.png 768w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/PWM-CONTROL-LEAD-WIRE-INPUT-IMPEDANCE-600x237.png 600w\" sizes=\"(max-width: 948px) 100vw, 948px\" \/><figcaption>1. &nbsp;THE FAN SPEED&nbsp; WILL DEFAULT TO MAXIMUM WHEN THE SPEED CONTROL INPUT IS LEFT UNCON<br>2. &nbsp;ABSOLUTELY NO INTERNAL PULL-UP.NECTED.<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FG_and_RD_Function_Introduction\"><\/span><strong>FG<\/strong> and RD Function Introduction<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"FG_Tach_output_type_Connection_Diagram\"><\/span>FG (Tach output type) Connection Diagram<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p class=\"has-medium-font-size\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Fan with FG function will creat a square wave output.You can know fan speed by sensing the output wave Frequency. Most dc fan have four pole.So when fan run for one round,there will be two high level pulse. About other Multipole brushless fan,high level pulse will be different.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; But please notice if you want to sense it\u2019s output wave,there is a external circuit. Please check the circuit Diagram below. There is no pull-up and VCC value limit.But please notice the Max Iin have to be small than 20mA.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"425\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM-1024x425.png\" alt=\"\" class=\"wp-image-5087\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM-1024x425.png 1024w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM-300x124.png 300w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM-768x318.png 768w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM-600x249.png 600w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/FG-DIAGRAM.png 1235w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption><strong>RD<\/strong> (Alarm output) connection Diagram<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Some fan have RD extra function.There is a alarm signal output when fan stop work.Please notice there are Two kinds of signal output. Different customer will need different alarm type.Please check the diagram below.RD alarm input voltage3.3V. RD output current20MA<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"588\" src=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION-1024x588.png\" alt=\"\" class=\"wp-image-5088\" srcset=\"https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION-1024x588.png 1024w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION-300x172.png 300w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION-768x441.png 768w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION-600x345.png 600w, https:\/\/cnmegatech.com\/wp-content\/uploads\/2022\/06\/RD-FUNCTION.png 1187w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Function of 3 Pin Fan &amp; 4 Pin Fan Most cooling fans will connect to a PC with a standard connector of some sort. Modern systems will typically use&nbsp;3-pin or 4-pin dedicated fan headers, though standard MOLEX 4-pin peripheral connectors are also used. From left to right: A 3-pin connector, a 4-pin connector and a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":5090,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"_joinchat":{"telephone":"+8613570567086"},"footnotes":""},"categories":[1],"tags":[893,497,564,512],"class_list":["post-5083","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-fancontrol","tag-axial-fan","tag-axial-fans","tag-cooling-fans"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/posts\/5083","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/comments?post=5083"}],"version-history":[{"count":3,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/posts\/5083\/revisions"}],"predecessor-version":[{"id":5135,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/posts\/5083\/revisions\/5135"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/media\/5090"}],"wp:attachment":[{"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/media?parent=5083"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/categories?post=5083"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnmegatech.com\/Axial-Fan\/wp-json\/wp\/v2\/tags?post=5083"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}