LED indicator for DC socket. Some problem.

[nguitar12]

Here is what I came up with so far. This circuit will turn off the LED when DC socket is plugged. How can I make the LED response reversely (like turn on when DC socket is plugged)? Thanks

[antonis]

http://www.diystompboxes.com/smfforum/index.php?topic=113132.msg1046268#msg1046268

Use switch 2 & 3 to effectivelly short-circuit the LED when unplugged..
(Anode to 3 & Cathode to 2)

[Digital Larry]

Use switch 2 & 3 to effectivelly short-circuit the LED when unplugged..
(Anode to 3 & Cathode to 2)

It'll work but also will drain current from the battery for no particularly good reason.

[antonis]

Use switch 2 & 3 to effectivelly short-circuit the LED when unplugged..
(Anode to 3 & Cathode to 2)

It'll work but also will drain current from the battery for no particularly good reason.

That's up to OP...

If it works with battery supply, he may use a P-N-P arrangement like the one in above attachement..

[nguitar12]

That's up to OP...

If it works with battery supply, he may use a P-N-P arrangement like the one in above attachement..

I just tried the second approach, no pnp version. It does work but the resistor get extremely hot. It is normal?

[thermionix]

I don't know how you actually wired it, but your diagram shows the external power charging the battery.  Not good.

[nguitar12]

I don't know how you actually wired it, but your diagram shows the external power charging the battery.  Not good.

Sorry, no battery there. Just to show the pin voltage. It is a PSU circuit.

[antonis]

I just tried the second approach, no pnp version. It does work but the resistor get extremely hot. It is normal?

It depends on the current..

For an about 2 volt difference across the resistor between led switched off and on (9 - 7) you shouldn't notice any remarkable temperature elevation..

If the resistor gets also hot when the LED is On then, probably, it's "wattage" is undersized..