Found in 1967 documentation, this circuit makes use of period transistors and drives a common light bulb. Nothing against it being adapted to use LED.
Found in a Radio Electronics from the 90s, this circuit generates a 1 kHz signal to serve as a...
This low noise circuit was obtained from a 1980s US RF publication. Transistors used are uncommon...
This circuit applies to other operational ones, other than the one indicated. The formulas next to the...