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 circuit can be used with any auio amplifier, converting it into a AM receiver. Antenna is a...
This circuit was designed to power the previous circuits of the wireless sound system, but it can...
This circuit is from the Motorola Linear Databook published in 1990. The circuit for 1 kHz can be...