1-Ttube reflex receiver (T1555E)

This one-tube circuit is equivalent to the previous one. We find it in a 1924 book by Gernsback, Power is made by batteries.

Two Transistor DC Motor Control (CB12043E)
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
Automatic Garage Lamp (CB16634E)
We found this circuit in a 1987 documentation. Its purpose is to turn on a garage light using the...
Logic level indicator 7400 (CB22407E)
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....