Article
Battery-Nearly-Empty Indicator
Simple but effective
This circuit gives a signal using an LED when the voltage of a monitored battery drops below an adjustable minimum value.
The NEI (Nearly-Empty-Indicator) consists of a voltage reference, a comparator and an LED indicator.
Materials
Extra info / Update
Note: Since the original publication of this project/article, some of the components, software elements, webpages and other elements might have been updated or changed.
Elektor PCB Service
Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits as the best services for its own prototypes and volume production.
Bill of Materials
COMPONENT LIST
Resistors
R1 = 4.7kOhm
R2 = see text
R3,R4 = see text
R5 = 680kOhm
R6 = 22Ohm
R7 = 15kOhm
R8 = 27kOhm
P1 = 10kOhm trimpot
Capacitors
C1 = 2.2µF 16V
Semiconductors
D1 = LED, green
D2 = LED, red
D3 = LED, high-efficiency, red
T1 = 2N6028
IC1 = LM10
Miscellaneous
Prototyping board e.g. Elektor UPBB (Elex) Type 1
Resistors
R1 = 4.7kOhm
R2 = see text
R3,R4 = see text
R5 = 680kOhm
R6 = 22Ohm
R7 = 15kOhm
R8 = 27kOhm
P1 = 10kOhm trimpot
Capacitors
C1 = 2.2µF 16V
Semiconductors
D1 = LED, green
D2 = LED, red
D3 = LED, high-efficiency, red
T1 = 2N6028
IC1 = LM10
Miscellaneous
Prototyping board e.g. Elektor UPBB (Elex) Type 1

Discussion (2 comments)