I was wanting to run a small 12v load off a 12v dc 5 amp adapter with a timer.

Is it preferable to leave the power supply plugged in constantly and have a 12v timer switch the load or to use a 120v timer to switch the power supply on and off which in turn would power the load.

The load being a few LEDs being switched on and off twice daily.

I was considering just switching the load because it would be easier on the power supply.

My goal is to increase the longevity of my project.

 

It is probably a close toss up, out of the two I would pick remove power to the power supply when not in use.
Max.

 

I saw some new "energy efficiency" requirements coming around to address people leaving their cell phone chargers constantly plugged in..

So the "greenest" answer is to disconnect the power source..

 

Use electronic switch instead of mechanical switch for longer life, no matter if it’s on 120V or 12V side.

 

I'm with mcgyver. As long as this thing doesn't sit unused until the capacitors dry out, better to disconnect the vampire load. A plain, old, hardware store timer will do the job.

Vampire: something that sucks your assets while doing nothing productive.

Edit: I see Max agrees. I just didn't read it closely enough.

 

Great. Thanks for the advice guys.