We found this circuit in the 1989 Radio Electronics Experimenter. The circuit uses common components, and the thermistor is supposed to determine the value of the trim potentiometer.
The circuit is from an Electronics Hobbyst Handbook from the 90s, being valid for panels of the...
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
This circuit is from an American publication from the 60's. The power is on the order of 600 mW....