Resistor ID

That’s a good idea -

I was going to suggest searching for a circuit diagram, but I doubt that exists for something simple…

It’s just a really really low quality shunt voltage dropper, if South London makerspace can’t figure out what value of resistor to put in we should simply give up doing electronics

4 Likes

Hi Joe
I tested V across the motor terminals (the motor works :smiley:) with a range of R values as below. Seems like you were spot on with 180R. I don’t think I need to make any adjustment for lack of load, but if that’s not correct let me know.

I now need to order a single 180 ohm resistor :joy:

Thanks again for your help… SLMS can indeed fix a low quality shunt voltage dropper! :trophy::grinning:

  • 176R gives 155 VDC and the motor sounds fine
  • 137R gives 160 VDC
  • 57R gives 165VDC and the motor sounds a bit fast

The gadget is a “water pick” which pumps water through a nozzle for cleaning braces (of my cousin’s 14 year old) and I tested it without any water

2 Likes

By the way… anyone know what this is or what it should do? Not sure where it fell out from

All good as long as nothing is getting too hot

It’ll be the on load voltages that make a difference

2 Likes