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A project log for Temperature control for small modeling iron

Adding a small circuit for exact temperature control to a modeling iron

Edgar KoglerEdgar Kogler 11/10/2019 at 17:410 Comments


I disassembled the iron and started choosing the controlcircuit and a fitting thermistor.

Since thermistors ready for 300°C are rather expensive I chose one with 150°C limit.

An alternative solution seemed to use an existing thermostat from an baking oven, but they are too big for my purpose.


I chose the circuit of Oliver Pering:

I had a nice time calculating resistor values for the voltage dividers used to switch the heating via the OpAmp (the good old workhorse, a historic LM741 ;-) )