Supply Voltage Monitor with 555 IC

This is a supply voltage monitor circuit, an indicator to show if the power supply is in good condition. Designed using the IC 555 timer, this circuit will flash the LED1 when the supply voltage surpass preset level.  With flashing indicator, at least there will be two benefits, first, the power consumption will be lower since the indicator doesn’t have to continuously emit the light, and the second, the flashing light gives more attention to the user. The C3 is used as flash rate controller, you can change this value for different timing.  Here is the schematic diagram of the circuit: