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, obtained from a 1965 magazine, can still be assembled using some modern equivalent...
We found this circuit on an Elektor from the 90s. The frequency is given by capacitor C1. The...
This powerful regulator, shown in the figure is for 5V (TTL) is suggested by Motorola and makes use...