Solenoid control circuit

[EEnovice]

Hi,

When controlling a solenoid, many circuits use a MOSFET or Darlington driver to switch the negative terminal of the solenoid to ground - which activates the solenoid. Can one use a simple SPST switch between the negative terminal of the solenoid and ground instead of the driver circuit? I don't know how to post schematics here or I would have posted a picture. This is a low power valve application...5W max @ 24VDC

Thanks!

 

[VEBill]

Basically yes. The transistor to ground is essentially the same thing as a switch to ground.

But there are a hundred things to consider. For example, perhaps the solenoid has a duty cycle limitation that the existing system monitors and controls - a switch would fail to control it and it might burn up. Also, inductive kick-back (current wants to keep flowing and makes a big spark). There are many such system-level things to consider.

 

[CarlPugh]

DC solenoids usually require a high voltage to pull in and a lower hold voltage to prevent the solenoid overheating.

A transistor is frequently used to apply full voltage for say 300 millisecond and then turn the voltage on and off at a high frequency to obtain a lower average voltage.

Ross Engineering Corporation,

http://www.rossengineeringcorp.com

among others sell a device to power DC solenoids.

 

[dydt]

...or you can use the output to drive a small relay...and that small relay will drive the solenoid.

 

[JTreglio]

We use 24 V dc solenoids to control air-actuated valves in our vacuum systems and hydraulic systems. I don't think we have a single one that uses a transistor or Darlington, so I would say the answer is yes.

Jim Treglio
Tribo Coating LLC