Under voltage indicator Circuit Diagram as use for battery equipment. This is a meter counter circuit in this circuit due to the low duty cycle of flashing LED, the average current drain is 1 mA or less. The NE555 will trigger the LED on when the monitored voltage falls to 12 volts The ratio of Rl to R2 only needs to he changed if it is desired to change the voltage point at which the LED is triggered.
Under voltage indicator Circuit Diagram
