This circuit was found in a 1967 RCA manual. The transistors are of the time. The adjustment is made to read 7.15 V on the charged battery and the charging current is 3.2 A.
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...