Code practice neon oscillator (T430E)

Found in a 1938 Radio handbook, this circuit must be connected to the input of a good amplifier. Other similar versions can be found on this website.

200 Hz Transistor Tunable Filter (CB1457E)
This circuit is from a 1975 technical documentation on filters. The FET can be a BF245 and the...
Li Ion Battery Charger (CB5410E)
This single-cell Li-Ion battery charger was found in a 2005 Linear Technology manual. The circuit...
Gain 10 Non-Inverting Amplifier MC1436 (CB4014E)
This amplifier is from Motorola's 1990 Linear Databook. The circuit can be used with operating...