[time-nuts] High accuracy temp controller ckt

[Mark Goldberg]

I've built a small temperature oven to test the TCXOs I produce. It
contains both power resistors for heat and a TEC for cooling and extra
heat. It is controlled by an Arduino and takes commands to change the
setpoint from the USB / Serial port. It is a PID controller with some
dither also, with modifyable parameters and some nonlinear control. I did
not implement automatic tuning. It's a little rough and largely
undocumented, but functional. I used a motor bridge to control the TEC. A
relay board failed quickly. The TEC requires fans on both sides to work
acceptably.

Pictures attached hopefully. I could try to provide more info if needed.

Mark
W7MLG
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