This circuit was found in a Signetics documentation from the 1980s. The integrated is a PLL and the SCR is a general purpose type The pitch frequency is given by R1 and C1 as formula next to the diagram.
This power amplifier configuration can be used in a public address system (ads) in the car. The...
This circuit was found in Philips documentation from 1967. The phototransistor is from that time,...
The oscillator shown in the figure can generate signals between 3 and 15 MHz approximately, depending...