I want to make a small radio where the battery is connected to the socket by inserting the earphones into a 3.5mm socket - to avoid having a separate on/off switch.

Is there such a thing as a normally open 3.5mm headphone socket? I can't find one which is described as such - but probably I just don't understand the schematics and how you would connect them to achieve this..

I have some sockets like this

http://www.rapidonline.com/Cables-Connectors/TruConnect-PCB-Jack-Socket-Stereo-3-5mm-20-0137

Could anyone tell me - can I use this to connect the battery when the earphones are inserted, and if so, what pins would be connected to what?

Thanks

 

You cannot use this jack to connect the battery because contacts B&F and G&E are shorted to each other. When inserting the plug into the jacks the contacts open. Generally contacts D& E are connected to the audio output source like speakers. When the earphone plug is inserted the audio to the earphones and turns of the speakers.
I am not aware of a jack to do what you want to dol

 

Since you want to make the radio, do you have a schematic? Sometimes it may be possible to power the radio thru' the earphones itself.

Ramesh