Electrical – adding a “power output button” to a cheap bench power supply

buttonoutputpower supply

I've an old and cheap Atten TRP3005T Take a look at atten site

I have seen more expensive device that had a specific button that always disable the current emission every time you power off the device.

This is a security feature to avoid disastrous error when you attach a device to the power supply when the power supply is off and has been left to wrong settings (happen to me.. but without consequences… 15 volts on an Arduino when I want to use only 9 volts to test it)

Is there a way to add the same feature to my power supply ?

I think that I need to build a circuit with a dual mosfet but I'm not enough skilled to design it by myself…
Also I'm not sure if this option draws power from the power supplier and can make some strange side-effects to power output like wrong value for voltage.

Best Answer

If you can figure out the internals of your power supply, adding a relay and a momentary push-button is a fairly simple task, perhaps with an added LED for feedback. (Or an illuminated momentary push button I guess.)


simulate this circuit – Schematic created using CircuitLab

Once it's on it would stay on till you turn off the supply though, but you can add a second, normally closed button to disconnect.