Found in a 90s documentation, this circuit makes use of D1, a switching diode that is uncommon today. D3 is an LED. The circuit monitors 12 V batteries.
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. |...