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Illuminated Switch Question.

Arnak

Apr 1, 2011
26
Joined
Apr 1, 2011
Messages
26
Hi,

I have a strange thing happening with an illuminated switch.
It is a SPST switch with an inbuilt LED for illumination when the switch is on.

It has 3 terminal, gnd, led/power out and power in, it works at 12v.

I am using it to switch onn/off a 5v supply as it is the only switch I have spare.

Now I appreciate that the led will not illuminate at 5v, so I added a led to work on 5v from the output through a 150 ohm resistor to ground, this works fine when the switch is on, showing that the switch is in the on position.

However when the switch is in the off position the led is slightly lit, showing that a reverse voltage is flowing through the switch!

How is this possible please, or is the switch faulty.

Thanks for any advice.

Martin
 

Audioguru

Sep 24, 2016
3,656
Joined
Sep 24, 2016
Messages
3,656
An LED is a diode then a reverse voltage will not cause it to light.
Why do you think there is a reverse voltage?
Which LED is slightly lit? The one in the switch or the one you added somewhere?
Can you calculate a new resistor for your 5V supply and replace the existing resistor?
Here is the schematic:
 

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Arnak

Apr 1, 2011
26
Joined
Apr 1, 2011
Messages
26
Hi,

Thanks very much for the replies.:cool:)

I have solved the problem, it was me being an idiot....

I had incorrectly wired the supply 5v to the groumnd pin of the switch!!!!!

Can I use the excuse that it was a senoir moment please?

Martin
 

Kiwi

Jan 28, 2013
471
Joined
Jan 28, 2013
Messages
471
"Senior moments" are allowed. I have a few myself as I get older.
 
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