Three-phase converter (CB21931E)

This circuit was found in the RCA Power Transistor manual from the 70's. The circuit uses power transistors of the time.

Transistor Tester with the 741 IC (CB1497E )
In the figure we have a configuration that allows to test NPN transistors and with the addition of a...
Telephone relay (CB10153E)
This circuit can be designed with ease today, as its components are common. We found it in old...
Intermitent Siren Using the 555 IC (MSB063E)
This siren produces an intermitent sound given by the characteristics of the two oscillators using the...