Relay Driver

Thread Starter

aac044210

Joined Nov 19, 2019
178
Hi:

I have a 5 volt relay that requires 70mA of current in order to energize the coil.
I am trying to get a driver to work using a 2N3904 transistor, a 1N4148 diode for
the flywheel and a 1KΩ resistor on the base. The emitter is grounded. I want a 5
volt level on the base to trigger the relay. It just doesn't work. Any ideas?

Thanks
 

eetech00

Joined Jun 8, 2013
2,043
Hi:

I have a 5 volt relay that requires 70mA of current in order to energize the coil.
I am trying to get a driver to work using a 2N3904 transistor, a 1N4148 diode for
the flywheel and a 1KΩ resistor on the base. The emitter is grounded. I want a 5
volt level on the base to trigger the relay. It just doesn't work. Any ideas?

Thanks
Sounds like it should work.
Maybe something wired incorrectly or a bad/incorrect part.
 

AlbertHall

Joined Jun 4, 2014
10,558
Is the relay operated all the time or never operated?
The circuit as drawn should work so it would seem it is not connected as per diagram.
Give us some photos. We may be able to see the problem.
 
Top