Hello,
My friend and I are designing a variable DC power supply controlled by using touchscreen and arduino. Our super told us to use pwm to control the voltage regulator instead of using variable resistor or potentiometer. What kind of semiconductor devices (TRIAC, DIAC, MOSFET, etc..) can we use to control the regulator from the touchscreen?

We really do hope you'll help us because we are new in this things (PWM and touchscreen).

thanks.

 

And the specification for the proposed power-supply is...?

You can control any device from a touchscreen but that is not the issue.

 

So this is a homework?

 

What kind of semiconductor devices (TRIAC, DIAC, MOSFET, etc..) can we use to control the regulator from the touchscreen?
thanks.

Typically, a power MOSFET is used as the switching device. There are lots of IC's available that do the PWM, and it's possible to use the arduino too. Search for 'switch mode power supply', you'll get tones of information.