Low battery indicator

  
Under good battery conditions the LED is off. As the battery voltage falls, the LED begins to flash until, in the low battery condition, the LED lights continuously. Designed for a 9-volt battery, with the values shown the LED flashes from 7.5 to 6.5 volts.
Low battery indicator - schematic

The transistor is the BFY90 and the IC is the SN72741P.




Leave Comment

characters left:

New Circuits

.