This circuit can be used with 5 to 15 V sources and the zener diode must be chosen according to the trip voltage of the protector. The circuit blows the fuse when the voltage exceeds the zener value.
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...