PWM circuit to control DC motor 12V

[moonstreat]

hello, I wonder if there is any way to regulate the speed of my motor.

There is some circuit that makes adjusting the speed of DC motors?

 

[MrAl]

Hi,


How much current does your motor require?

 

[moonstreat]

requires 500mA current

 

[Hero999]

What sort of motor is it?

A brushed motor?

There are many different ways of doing this, one is to use a PLL to lock the frequency of pulses from a tachometer to an oscillator.

 

[moonstreat]

is my motor:

**broken link removed**

Uploaded with ImageShack.us

 

[Hero999]

Do you mean regulate as in constant speed, i.e. adding a small load to the motor doesn't reduce its speed?

That requires a closed loop system.

If it's just a variable speed control, it's pretty simple.

 

[moonstreat]

yes I want a system of speed control! please post for me

 

[Hero999]

Here's the simplest speed control I know of.

Replace the lamp with the motor with a diode connected in reverse parallel.

**broken link removed**

 

[bychon]

Is $20 plus shipping simple?

 

[moonstreat]

What is the mosfet that thou hast shown on this circuit?

 

[Hero999]

It's a generic P-channel MOSFET, it's not critical as long as it has a high enough voltage and current rating to power the motor.

It can be changed to N-channel but the response of the pot. will be reversed.

**broken link removed**

 

[MrAl]

yes I want a system of speed control! please post for me

So i guess all you want to do is be able to vary the motor speed, without concern if the motor slows down a little by itself when a load is applied, or you are using a more or less constant load anyway.