ON/OFF Switch with LED Pilot Lamp - How to Solder???

[leonetu]

I'm trying to mod a Dell DA-2 power brick to have an ON/OFF switch (with pilot lamp) for the trigger and could not find a reference to follow. Im using a Zippy P2-Series switch to turn on/off Pin 5 (trigger) instead of shorting it directly to ground. I could just use a simple switch but I want to have the option of going on standby when I leave the PC off for a long time (say, when I'm out of town). Can anybody post a proper reference for soldering or give directions, please? TIA!

 

[InvalidError]

Since the only power coming out of the brick while it is on standby is whatever you can draw from the 'trigger' pin, the only power available to light up the LED is whatever you can draw from the trigger before the brick turns on. That current may be too small to provide any useful lighting.

Assuming the trigger can provide at least a few mA at whatever voltage your LED needs before the brick turns on, the way to wire it would be to put the LED with a current-limiting resistor in parallel with the switch. When the switch is open, the trigger voltage/current gets applied to the LED and when the switch is closed, the trigger is shorted to ground to turn the brick on.

If the trigger is operated with nano/micro-amps, you will not be able to produce any meaningful light with it unless you use a pulse circuit to dump charge from a capacitor into the LED but depending on how small the trigger current is, your 'standby' LED might only be able to pulse a few times per minute due to the capacitor's long charge time.

 

[leonetu]

Thanks IE, that was very helpful! I went ahead and installed a regular rocker switch for my HTPC build but will retry the LED switch with my media server, which I am converting to DC-DC.

 

[leonetu]

Best answer selected by leonetu.