This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio Electronics from May 1963. The indication is by an analog instrument.
This circuit uses unijunction transistors and drives a small speaker through an output...
This interesting game was found in a 1987 publication, but it is very simple and can be easily...
This circuit uses a thermistor or NTC as a temperature sensor and provides the indication on an...