Voltage Level Detector (CB22135E)

We found this circuit in an English documentation from the 80's. Transistors are general-purpose types.

1000 second timer (CB23601E)
The existence of field effect transistors at the input of the integrated circuit (operational...
Two Color Sequential (CB4409E)
This circuit using current components was found in an old documentation. It is a sequential circuit...
Detector with tunnel diode (CB23850E)
In the figure we have a signal detector using a tunnel diode. The circuit is from a Radio...