
heater control circuit for a low power (~40W) proofing oven. the thermistor
element is a 10k NTC with B 25/50 constant of 3380K. Setting the trim pot
VR1 to read 1.25V sets the hold/max temperature to within 1 degree C of 25C
(~75F)

the power mosfet is an IRF530N, and as wired, max input and load of the circuit
is 20V and around 5A.

RV2 can be adjusted to change the lower threshold of the schmitt trigger.
