This circuit was obtained from Dutch documentation from 1964. The components are of the time, but current equivalents such as BC548 to BC108 can be used.
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...