This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical system with a propeller-driven magnet to count pulses with a reedswitch.
This 1 A circuit was found in a Philips documentation from 1966. The transistor is of the time,...
This FM transmitter circuit was found in a Japanese publication in 1975. Equivalent transistors can be...
In the figure we have the basic configuration of a 5 V regulator using an operational 741. In this...