How to wire an indicator LED to light if a plug has something plugged into it?

Question

I have a 24 VDC circuit, there is a plug in the middle of the circuit. I want to light an LED when something is plugged into the circuit. Cicuit is open when nothing is plugged in.

Thanks

Answer 1

I believe this is ur circuit
_______
|
|+........... |
24V.....plug
|- ............|
|_______


if this the case then this will work
_____________R1______C.................
| ............... |............... |......................
| ................|............. R3........................
| ...............R2 ............ |___ B ...............
| .............. | ...........................................
| ...............|........................ E ................
| ...............|........................ |..................
| ...............|...................... LED................
| .............. |___________|(-)..............
|+ .............|.............................................
24V.....plug...........................................
|- ............|................................................
|_______|..................................................
note: ignore dots(.) as spaces
design R2 =max 1.2Kohms coz it has to drive LED of 20mA
R3 = around 47kohms
R1= depending on load at plug
C, B,E= Collector,Base,Emitter of a NPN transistor
Actually all values depend on load resistance.
thank you
______________________________
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||Satya Meva Jayate||

Answer 2

If I understand your question correctly, one side of the plug is +24 VDC and the other side is ground? The plug supplies 24 VDC to something else?
If this is the case - you can place a low ohm resister in the plus line and put your LED in parallel with the resister - make sure of the correct polarity - when there is a completed circuit and current flowing, the small voltage drop across the resister will light the LED.

Answer 3

Put a relay in series with the plug. When current goes through, it will complete the circuit for the LED.

Answer 4

years since for me, but
seems like just
take a resistor and the LED in parallel and put
that in series with the plug. When current flows,
there's voltage across the resistor and the LED lights. But I have no idea of the impedance of the
LED, so....just an idea.

Answer 5

flow to radio shack and get the adapter plug to characteristic to the neon lights they value about 3 funds and this may show you how to to plug them in to the cig-lighter,it quite is a thanks to attempt this one,good success.