This circuit was obtained in a 1967 Electronics World. The components are still common today, the SCRs can be replaced by equivalents and the unijunction transistors the 2N2646.
This timer was found in the Texas Instruments 1996 linear applications manual. The relay must be...
This circuit compares two light intensities, providing the indication on an analog instrument. The...
This circuit was obtained in a 1983 publication. It is a 1-transistor voltmeter, capable of...