I’ve never considered that. I just assumed that a MOSFET would be the best option for switching since there was high voltage present. I did put in an order for more MOSFETS so I’ll likely keep with that, especially since the PCB I made for the clock uses a circuit like the one listed.

You might be able to run the MOSFET common gate. Connect gate to +5V and source to your output. A typical IRF820 would easily manage 1A at that gate voltage and you need a milliamp or so, but you might not have a typical IRF820.

 

When the pulse output is 0 volts, I am getting 7.5V across the collector of the BJT.

Are you sure that your transistor is connected correctly? The 7.5V between collector and ground sounds like Base-Emitter reverse breakdown voltage to me.

 

Are you sure that your transistor is connected correctly? The 7.5V between collector and ground sounds like Base-Emitter reverse breakdown voltage to me.

Yes it’s hooked up correctly, yesterday it was deemed that both the mosfet and BJT were bad. I have another BJT but the MOSFET should be coming in today or tomorrow. Even without the BJT, the gate voltage on the mosfet was 3 volts instead of 12.

 

Yes it’s hooked up correctly, yesterday it was deemed that both the mosfet and BJT were bad.

Easy enough to verify with another 2N3904 before the mosfet arrives.

 

Turns out the MOSFET was dead on arrival. So after replacing that, and the BJT. Everything is working perfectly fine. Thank you all for your help in testing the MOSFET and being able
to get to that conclusion.