Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Speed control circuit for a 12v computer fan

Status
Not open for further replies.

dmcmillen

New Member
I have a 90mm, 12vdc, 200ma computer fan that I need to control the speed in an application unrelated to the computer. Power supply is 12v, 400ma. Does anyone have a circuit schematic that I could use to accomplish this. I tried the attached circuit with a 555 timer but I'm not getting any speed control with that circuit; just full speed. I believe these fans typically don't work well at voltages below 50%. I tried increasing the capacitance of C1 to bring the frequency down (on recommendation of circuit designer), but without any luck. I am an amateur here so I could use some help. Thanks!
 

Attachments

  • Schematic.jpg
    Schematic.jpg
    37.2 KB · Views: 473
Last edited:
pwm

I would double check that everything is wired correctly. If the 555 is not working you would have your symptom.
 
compare it with these which have little difference:

**broken link removed**

**broken link removed**

or with this which has much more differences:

**broken link removed**
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top