- 27 Oct 2009
I can remember when, what we now refer to as PWM, was just called a transistorised controller in the model railway world - mind you, that was a few eons ago, and I soldered up a fairly inexpensive controller kit; the speed control on small locos was fantastic. Sadly, it's been stored on a board in the garden shed and the low temperatures and humidity have killed it off. In its day, it was better than the Gaugemaster controllersOK, then that is as I asked, the same size about 5 x 11 mm, so indeed the common size for a 10 mfd, npo electrolytic.
I agree with Phil, keep the voltage near the original. Some of the advice above implies you can lower the voltage with settings, but all of this equipement is PWM, pulse width modulated, which means you control speed and "voltage" by varying pulses of FULL VOLTAGE, as these circuits are just an on off switch with varying "on" times.
The point here is that using a much higher voltage and then narrowing the pulses on time way down is not the same as longer pulses at lower voltage, you can get heating and other unwanted effects when there is a gross increase in voltage.