This circuit was found in General Electric documentation from 1964. It makes use of a PUT, called the PNPN planar key at the time. The circuit has two supply voltages.
This VCO makes use of components from the 1980s. The circuit can be implemented with modern...
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...