Electronic Thermometer (CB21356E)

This analog thermometer was obtained from an English documentation. The sensor is a common diode and the indicator a common milliammeter.

JFET variable zener (CB7478E)
We found this circuit in a 1977 Radio Handbook. The JFET can be of any type and the adj can have...
Double-T Oscillator with Diode Regulator (CB25913E)
This double-T sine wave oscillator was found in the December 1995 issue of Electronics Now...
Limit Alarm (CB5075E)
This limit alarm was found in a 1980s US documentation. Comparators can be equivalent and the...