This Public Address amplifier was found in a 1947 amplifier manual. The power supply uses two transformers with two rectifier tubes.
This charger can be used with one to four AA, AAA, C or D cells. The maximum current is given by R...
This wireless infrared remote sound transmitter is from an article published in the August 1988...
This circuit turns on an old cassette recorder when the telephone rings, thus enabling the...