i need some help about my project..im new to circuits and components.. im working on a power supply for controlling tamiya dc motor.. i used the pc power supply i hacked from my old pc to power the regular tamiya motor.. and it has 3.3V 22A, 5V 20+ something Amps and 12v 20A ..

1st question- is it ok if i use it even if it has so much amperage? how much is the voltage of this motor and its amperage?

i tried to make a pwm circuit using a NE555 and TIP31C for adjusting the speed.. but the TIP31c gets hot.. so its not viable.. i also tried LM317 as adjustable voltage regulator but it does not have enough power for the dc motor.

anybody who can help me design a simple circuit using pc power supply as a source even if the motor runs minimum of 30mins using pwm.. ..thanks in advance

 

So you want us to tell you the voltage and current the motor needs without knowing which motor it is.....

 

how much is the voltage of this motor and its amperage?

You can check the amperage drawn by your motor using a amperage meter, and volt using a volt meter.
Check this link to how to check the ampere
http://www.youtube.com/watch?v=yrpmq2FCnqs

 

1st question- is it ok if i use it even if it has so much amperage? how much is the voltage of this motor and its amperage?

First to be clear with power supplies:
Your PC power supply is providing several DC voltages lines with rated current.
The current which is displayed is the maximum current the power supply can deliver at the voltage, for example 12V 20A means you can draw 20 Amps at 12V = 12x20 = 240W power.
For this line you have to draw less than 20A because the supply is rated for 20A max.
So i think it's OK if you use your motor directly on your power supply, your motor will turn at constant speed, but which line you have to choose i don't know because you did't tell us the voltage needed for your motor.
Search on the motor if there is informations or model number then google it...

 

You'll need to supply the ratings of your motor.

.. and as a side note your PC power supply will have to be a quality unit because if it's a cheap generic I'll guarantee it can't supply its rated outputs.

 

thanks.. i got it.. i need to buy a multimeter with higher amps.. thanks paul and afternath and paulktreg..

 

the motor is 3v and 4A..

 

the motor is 3v and 4A..

Then connecting to 3.3V out from that psu unit will work!