Ringer 4 quadrant multiplier

Gaah, of course. Thanks. I compared both multiple times and never noticed. I changed it (needed more like 17.1k to get best results, it’s pretty sensitive) and it looks pretty much like yours:

Note: I’m seeing an average control current around 780 µA and maximum about 1 mA like this. Turning the pot down to about 8k gets you to around 1.6 mA average and around 2.3 mA maximum, which exceeds the safe limit for the 13700, so don’t do that! Perhaps a 10k fixed resistor in series would be a good idea.

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