This circuit with its light source was found in American documentation two years 70. Or transformer of the type found in small transistor radios of the time. The transistors are general-purpose.
This low power audio amplifier was found at 1992s Popular Electronics. Transistors are general...
This circuit was found in the October 1993 Electronics Now magazine. The output transistors form...
The presented circuit monitors a line indicating if it is busy if there is an extension. The...