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1
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2answers
70 views

Simulate tach signal of PWM fan

I have a power supply that uses a PWM fan with 4 wires. Wires: 12V (red), GND (black), PWM Control (brown), TACH Sig (white) The fan speed is controlled by the PWM control wire (brown). Fan speed is ...
0
votes
2answers
681 views

Arduino controlled PWM PC Fan

I am looking at getting 2 Evercool EC8015HH12BP 80x10mm (4-wire) PWM fans. However, i am looking at controlling the fan speed with the arduino via the PWM pins. I found the following diagram that ...
0
votes
4answers
429 views

Undervolting PWM fan from 12V to 5V [closed]

What will happen if I feed a 12 Volts rated PWM fan with 5 V driving voltage? Given all the other variables stay the same (PWM control signals) - will it reduce RPM? By how much? What happens to the ...
0
votes
3answers
258 views

20 Amp automotive thermatic fan PWM controller

I have an older car which tends to over heat in the summer, so a 20 Amp electric fan was added in front of the radiator. Currently its driven by a on / off relay. I want to build an Arduino PWM ...
3
votes
3answers
395 views

Cleanest method for measuring the reported speed of multiple computer fans?

This question builds upon this previous one How to interpret output of 3-pin computer fan speed sensor? which was asking about the 'sense' wire output from computer fans. I am designing a fan ...
3
votes
3answers
1k views

Why does a speed-controlled computer fan require 4 pins?

A "standard" computer fan has two pins; one for power, one for ground. A three-pin fan adds an additional pin used for the signal from the hall-effect sensor. A speed-controlled fan generally uses a ...
7
votes
4answers
2k views

How do I eliminate PWM noise when driving a fan?

I'm driving a 12V 0.11A brushless DC fan with PWM using an MSP430Gxxxx --> TC427CPA FET driver --> BS170 N-FET. The fan is on the low side of the FET. Even with a duty cycle of 90% and a frequency of ...
3
votes
4answers
6k views

How to interpret output of 3-pin computer fan speed sensor?

This question may be borderline between superuser and here, but I think it's more suitable for this site. I have a 3-pin 12 V computer fan and I want to interpret its speed sensor output. At the ...