simple led display warn battery low

Friends may meet the disadvantages of the electrical equipment that uses battery be battery like to finished the climax always. This equipment no help to give battery be finished have power upward again. But wait for warn when battery low be hurried change or charger to first be finished. This circuit designs to come to apply to volt since 3-15V the dot will to begin to show can fine with VR1. When voltage decrease down more location dot keeps LED bright immediately. The electronics part a little also just transistor BC547 and other. It usual Current about 3mA but enough LED bright will valuable about 15mA.

LED display low volt battery 9V using SCR
The LED stick bright when volt of battery model to load new get agree lower 8.3V ( for battery 9V). Which be minimum value that can agree, be a signal know that battery, want to load new already. The circuit can modify to go to apply to transistor radio for is warn change battery the grou ...
Bargraph Voltage Indicator by LM339
The circuit Bargraph Voltage Indicator used IC op-amp two quad voltage comparators to illuminate a series of 4 LEDs indicating volume level. The op-amp used in this particular circuit is the LM339. It is a popular IC and should be available from many parts stores. The 1K resistors in the ...
Integrated battery level indicator with 3 level led
This circuit is simple battery level indicator circuit. Which be simple complicated can see that the circuit has will LED keep for display arrive at 3 step. The work of the circuit be this circuit was fixed come to give a temple volt usual that about 11V-14V. Which will the level volt norm ...
Easy Test power battery by BC547
A friends at use the battery often meet a problem electric its energy is finished in important always may many good if there is the circuit warns before or there is the way checks at the beginning. By this circuit use the transistor just one and don't have to have power supply source. By ...
Strength meter using IC741
This strength meter the test can by catch 2 metals. From that time squeeze meet. It will make LED stick bright arrange prevent according to one's ability of squeezing the metal. The work of the circuit uses our body is formed lead the electricity changes to reach in the circuit. Which perfor ...