This circuit with 4 transistors can receive signals in 6 shortwave bands. The circuit is from a Radio Electronics from May 1958. The output is for high impedance headphones.
The LM3911 from National Semiconductor (Now Texas) is a temperature sensor that provides an output...
Found in a 1990 Electronics Handbook, this circuit causes an LED to flash when the phototransistor receives...
This circuit was obtained in a Portuguese publication in 1979. It is a simple code switch that...