This circuit was found in Philips documentation from 1967. The components are of the time, being transistors like BCY38 for TR1, BC108 for TR3, and others depending on currents.
This circuit was obtained from Popular Electronics of the 1990s. The circuit uses common...
The circuit shown uses an operational transconductance amplifier such as the LM3900. Transistors...
This simple Morse Code oscillator was found in a 1980s American documentation. The power supply...