I need an electronic device (circuit) that will act as a DPDT switch to run a 20ma 12vdc motor forward and reverse. The trigger to activate is a + 2vdc pulse to activate the motor in one direction and when signal is removed the motor runs the other direction. I do not want to use a standard DPDT mechanical switch or relay. Can anyone help me please.

Thank you, Ron

 

The circuit you need is called an H-bridge.
You can buy it ready made as L298N motor driver.

 

A SPDT center off toggle switch can control a motor driver like this one. The toggle switch is only switching a few mA, the module controls power to the motor.

 

Any H-bridge MOSFET will fulfill your purpose. You can choose from L293D, L298N, IBT-4 etc. depending on the specifications of your motor.

 

As an aside, that L297N board is sold by quite a few vendors where it always claims good for steppers, but the unit fails to include the neccesary current control ability needed for a stepper.
So good for DC motor only. !

Note: the L298N IC itself does however have the feature, just not facilitated on these boards.

 

The trigger to activate is a + 2vdc pulse to activate the motor in one direction and when signal is removed the motor runs the other direction.

Don't you also want an 'off' function?

 

While the old L298 is an H Bridge, consider the voltage drop (loss) using it. There are much better H Bridge modules available using MOSFETs. Google is your friend.

Ron

 

Don't you also want an 'off' function?

No I do not need a off position, the circuit need to be on all of the time and when triggered it reverses the motor.
Thank you, Ron

 

Are you going to reverse it instantaneously?
Then you must include some sort of SOA limiting.

 

How frequently does the 2V pulse occur, and what is its duration?