This is a modification of 0.05.
I read up some more on the subject of analog closed
loops and realized I'd make a silly mistake; it's
not just speed that's a consideration, but gain as
well, and no matter how big I made the filter, it
still had massive gain. Dropping the 1M gain
limiting resistor should let it stabilize
And it did. With the resistance at 10K instead of
1M, it slowly dropped from the maximum of 1.0A of
current until there was just 0.65V across the power
resistor, maintaining a constant temperature.
Putting my finger on the thermistor caused it to
increase power to compensate. Nice.
Note that since the circuit is operating in linear
mode, the power amplifiers dissipate a lot more
heat. It absolutely requires a heatsink.
Version 0.06 is the last breadboard version I will
build. Stay tuned for
the insulated canister, and the permanent version
of the circuit, v1.0.