This interesting circuit of an Electronic Design stores the highest voltage of two applied to its inputs. The circuit is from 1964 and can be adapted to use modern components.
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
Found in 1965 General Electric technical documentation, this half-wave circuit controls shunt type...
The power supply shown in the figure provides voltages between 0 and approximately 15 volts, with...