This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is 1000 M ohm.
Found in a Radio Electronics magazine from September 1958, this circuit has an LDR powered by the...
In the figure we have the simplest way to implement a power supply for a tunnel diode. The...
This circuit was found in a 90s Motorola documentation. The circuit uses two SCRs that must be...