Actuator Pwm Control

Thread Starter


Joined Jan 13, 2007

Hello and greetings for all.

In my first post i want to ask (and see if i can to explain), this problem for me:

I've a PWM 0-12 v signal (500 ma) and want to control a solenoid actuator that has middle point.

I connect the positive terminal pwm at middle point, and if i connect the other negative terminal to the actuator end one, move to right, if i connect it other side move to left.

All is fine! but here is my problem how to control with unique potenciometer in order to obtain gradual control for center, right and left?

I make the control with a potenciometer but it not have the wattage necessary and is not the correct, i think i need a transistor drivers for potenciometer control. But i don't know.

I should be very thankfully is anyone can help me or link to some circuit application for it.


Joined Apr 20, 2004

If it is just a matter of the middle and end points, a single pole double throw switch will do.

If you need to control the valve between the end points, then control gets more elaborate. Is this the case? and is your signal really pulse-width modulated, or just 12 volts DC?


Joined Jun 30, 2006
Do you have a graphic of your schematic? Can you get access to what controls the PWM? You'd probably want to adjust the middle either modifying the PWM circuit or mechanically.

Thread Starter


Joined Jan 13, 2007
Thanks for your answers.

I need to control the valve between the end points and start in one end and stop in other end.

And yes my signal is pwm generated by NE555.

BTW, in the meantime i solved the problem!

I connect the pmw signal to middle point coil.

And connect collectors 945's in end's and his emisors to ground,

then interconnect the bases in series with 10k potenciometer and inject the polarization via his middle terminal from a resistive divider 10k - 1k to get 1v.

The start and end of actuator with two relays connected to ends coils bypass to ground.

All was fine and work perfect!

Only i fried two 335 for mistake connections :p