This circuit trips by shorting the load to quickly blow the fuse when the voltage exceeds a certain value. The triggering voltage is set to R2. The fuse must be in accordance with the load to be protected.
This circuit adds a beep to turn on with car flashers that do not have this feature. A 47 ohm to...
This 80's circuit uses a small light bulb as an indicator, but an LED with the appropriate resistor...
This circuito from the 1977 GE Semiconductor Manual circuit provides timings from 0 to 90 seconds...