We found this circuit in a Hands-On Electronics from the 90s. The circuit must be connected to an external amplifier. Frequency control is capacitive, using an antenna for this purpose
This circuit allows you to read temperatures with a common digital voltmeter. We found it in the...
This circuit for the 1.5 to 15 V scaled ranges was found in a 1982 documentation, but uses current...
The integrated circuit of this 1976 configuration is the 7400 and the type crystal in televisions of the...