Found in a 1967 American publication, this circuit with feedback for two transistors has a gain of 20 times. Phototransistors are types of the time.
The A3906 integrated circuit from Allegro Microsystems (www.allegromicro.com) consists of a PWM...
This analog TV circuit can be used on a small transmitter. The circuit is from an 80's American...
This circuit is from an Electronics Now from the 90s. It applies to almost any operational...