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.
The components used in this National Semiconductor circuit are not common today, but the...
This 2001 circuit is used with transceivers to increase the gain of a microphone and thus obtain...
In the figure we have the configuration of a variable voltage regulator with two transistors and a...