Converting a 5v Relay to be controlled by a 12v signal input

Thread Starter

s200bym

Joined Aug 9, 2017
82
Hi all,

I need a 5v relay but the signal input needs to be 12v. Would I be correct in saying, all I need to do is swap out the J3Y NPN for another NPN transistor that can handle 12v at the base?

Thanks,
Mike.

5V-Relay-Pinout1.pngSchematic.jpg
 
Last edited:

crutschow

Joined Mar 14, 2008
34,455
I need a 5v relay but the signal input needs to be 12v. Would I be correct in saying, all I need to do is swap out the J3Y NPN for another NPN transistor that can handle 12v at the base?
No.
Just add a small diode (e.g. 1N4148) from the transistors base (anode) to emitter (cathode).
But your schematic shows a PNP, not an NPN.
 

Thread Starter

s200bym

Joined Aug 9, 2017
82
I appreciate your help. I managed to find another relay to try it out and it worked. I tried it on a previous relay a while back (same make and model) and the transistor got too hot to touch. It must have been a dodgy one.

Thanks.
 
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