OK, so I am still trying to figure out why you would need or want a PMW with 2 knobs on it. The first knob adjusts the width of the pulse and the second adjusts the frequency. Why would you want to adjust the frequency? Will different frequencies work better depending on what the area of your plates are?

What am I missing? I was going to buy a PMW, but don't want to spend more than $35 or so. I'm pretty handy, so making one isn't out of the question too, but then which schematic is a good one?

TIA

Dean