This circuit is from 1975 documentation. Transistors such as 2N3055 can be used and the transformer is of a special type. R1 is 200 ohms and R2 is 10 ohms.
We have here a simple signaling circuit for two common incandescent lamps, which is used for...
This amplifier for instrumentation with differential input is from the factory manual of the...
This circuit was found in a Popular Electronics from the 90s. It is based on components still...