This battery-powered 3-valve circuit was found in American documentation from 1947; Two batteries are used, one high voltage and one low voltage for the filaments.
This modulator circuit for AM transmitters was found in a 1960 Sylvania transistor manual. Modern...
circuit is used to increase the sensivity of a relay. A 50 to 100 mA relay can be triggered with...
We find this circuit in an Electronics Now. The indication of the logic level is done on a...