Power Grid Monitor (CB21154E)

We found this circuit in a Popular Electronics from the 90s. Its purpose is to monitor a power line. The circuit uses optical couplers of the time.

| Clique na imagem para ampliar |

1000 second timer (CB23601E)
The existence of field effect transistors at the input of the integrated circuit (operational...
Siren Sound (CB23943E)
This circuit generates a siren sound. It was found in the April 1969 Radio Electronics magazine. The...
Selectable gain amplifier (CB7127E)
Suggested by Siliconix in documentation from the 90s, this circuit can present gains of digitally...