9 volt AC transformer load question.

Thread Starter

CAB55

Joined Nov 24, 2020
17
I will have a control module circuit board that requires a 9 volt transformer. This will control a spot welder‘s current and contact time. I also wish to add a small
1 1/2” brushless 5 volt DC 0.25A fan that will be running all the time. I plan to build a separate circuit to convert a 9 volt AC transformer to the 5 volt DC needed for the fan. Can I use the same transformer to power both boards?

Thanks, CAB 55
 

wayneh

Joined Sep 9, 2010
16,531
Can I use the same transformer to power both boards?
Sure, as long as it can handle the combined current of the loads. You'll just need a rectifier and a 5V regulator.

I'm expecting someone to tell us you could get by with a single diode and no regulator. The pulsing DC would exceed 5V, but the time-averaged voltage would probably be OK for the fan.
 

Thread Starter

CAB55

Joined Nov 24, 2020
17
Sure, as long as it can handle the combined current of the loads. You'll just need a rectifier and a 5V regulator.

I'm expecting someone to tell us you could get by with a single diode and no regulator. The pulsing DC would exceed 5V, but the time-averaged voltage would probably be OK for the fan.
Thanks very much Weyneh!
 

Thread Starter

CAB55

Joined Nov 24, 2020
17
You can get fans that run off 120 or 240, I have them in mine.
Thanks Wolframore. I’m hoping the small fan, already part of the box I’m using for my housing, will be sufficient otherwise I will need to add an external 110volt fan.
 
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