We found this circuit in an American documentation from the 1990s. The circuit is based on the LM3909, a low power oscillator from National Semiconductor.
This simple indicator circuit was found in a documentation from the 90s. Trimpots can have values...
Originally in the 1992 publication, this amplifier was recommended for use with record players....
This small transmitter can send its signals to a receiver placed at distances up to 100 m. The...