At 1/8/2007 15:22, you wrote: >Hi Bob, > I would like to get a copy of that circuit if you have one available. > >Thanks,
OK, here is the circuit I used. The original National Semiconductor circuit had a 30 K resistor in series with a 400 uF cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section. I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 uF cap in series with the 10 megohm resistor to 5 uF. That cap is a non-polarized paper capacitor; I believe a 4.7 uF non-polarized ceramic should work as well. The 1/4 watt heater resistor & LM34 temperature sensor are mounted on the same side of the crystal but separated as far apart as possible. Bob NO6B
445.46 TX temp. stabilization.png
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