LED_BJT_Switch

[antonis]

I'm building a 8-output Spyder PSU (100mA) and I've just decided to put an LED indicator on each individual output for visual check..
Output plugs are 5.5/2.1 mm with negative center pin and On/Off switch on third lug which will be connected to +9V via the second lug when switch is ON (No DC jack inserted..)

Is the below circuit O.K. or am I missing something (including an extra cup of coffee, perhaps..)..

[slacker]

That looks like it should work. You can do it simpler than that though, connect the LED between the 9 volt lug and the switched lug, with a current limiting resistor from the switched lug to ground. With no DC jack inserted, the LED is shorted out so turned off, plugging a jack in removes the short and LED turns on.

[PRR]

What he said.

[antonis]

Thanks guys...!!! 

I was thinking of the current consumption when the LEDs are OFF, which in this case is quite bigger than the active LED state...
(in my case it should be less than 20μA per LED..)

Anyway, it will be less than 1mA (saving also extra work and components..) so you've just made my day...!!! 

[PRR]

> current consumption when the LEDs are OFF

I had to look back.

No battery.

OFF-suckage is NOT an issue for a wall-supply. Or not worth second-thought.