December 30, 2012
I was wondering if this could be used to short out a portion of the resistance track in a potentiometer? For example, guitar volume pedal pots only move about ¼ turn. They can rotate over the full range, but when installed in the volume pedal, the linkage only moves it about 90 degrees. So they make these special pots, which are expensive and hard to find and take a long time to get. The resistance track is only over that ¼ turn, and then the rest of the way around is close to a short. Obviously you have to pry the back cover off to see all this. So I’m wondering if I good use this pen on say a 1Meg linear pot, and draw over ¾ of the turn (OK a little less, since it’s not 360 degrees), and end up with one of these special pots?
Hope this makes sense, thanks in advance for your thoughts
about 10 months ago
The video above uses +5V for the high current source. But what if you need to switch 12V, or even higher? So I shot a second video that shows how to use a simple NPN transistor to drive the Gate, allowing the Source voltage to be much higher than the +5V, or +3.3V
P-Channel MOSFET with logic level Gate is a great way to really beef up a digital output, to do some serious power switching. Thanks to the tiny Rdson, the heatsink is often optional. I did a YouTube video about using P-channel MOSFETs with Arduino, showing and discussing switching speed versus gate drive current, and comparison to (more or less) equivalent transistor circuit.
Coincidentally, I was using this same part, Fairchild NDP6020P.
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