Power Failure Alarm (CB25348E)

This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July 1990 issue of Radio Electronics magazine.

| Clique na imagem para ampliar |

VFO with FET (CB4053E)
This circuit for the 3.5 MHz band (80 meters) was found in an old radio amateur documentation. The circuit...
Self-biasing JFET circuit (CB25563E)
This JFET amplification stage was found in the April 1993 issue of Electronics Now. The input...
Voltage Monitor and Comparator (CB6086E)
We found this circuit in a Popular Electronics of the 80s. The circuit can be made with almost any...