This 3-digit digital gauge was found in the July 1900 issue of Radio Electronics magazine. The circuit is based on the CA3161 and CA3162 A/D converters of the time.
This circuit uses a CA3140, an operational amplifier with FETs in the input stages. Equivalent can be...
Found in a Popular Electronics from the 90s, this circuit has a configuration that has been widely...
This circuit was found in an American 80s circuit manual. The components used are unusual. The...