This circuit using only transistors was obtained from Ferranti's 1969 documentation. It can be made from modern transistors. The circuit is 4 bits.
Although indicated in the original publication of the 1980s as a capacitance switch, the circuit...
This is a circuit found in a 1970's Radio Electronics. The circuit works with virtually any triac...
This circuit, found in an old 1967 publication, cuts the current from a source when the current...