This symmetrical four voltage source was found in a 1968 Motorola documentation. The circuit is of a type that was commonly used in that time amplifiers.
Found in Popular Electronics of January/February 1969, this transmitter has a few meters range and can...
Found in 1969 RCA documentation, this circuit maintains constant current in the filament of a lamp...
Found in a 90s 73 magazine, this circuit uses an unusual component today which is the XR2206. |...