Found in a 1966 documentation, this “coin finder” uses components from the era operating at 2.1 MHz. The circuit uses an audio amplifier for detection.
This circuit was found in Maxim documentation from the 1990s. The RC circuit determines the...
This Vienna bridge multi-band oscillator circuit was found in a 1974 Ferranti transistor manual. The...
This circuit can be used as a shield to control the matrix flow of 100 LEDs from a single output of...