12V Battery Charge Nominal Discharge (Low)
Indicator Circuit This circuit monitors car
battery voltage. It provides
an indication of nominal
supply voltage as well as
low or high voltage. PARTS LIST
R1 1.5kΩ
R2 1.5kΩ
R3 1kΩ
R4 1.5kΩ
R5 1.5kΩ
R6 10kΩ
R7 10kΩ
VR1 10kΩ Preset
VR2 10kΩ Preset
D1 Green LED
D2 Yellow LED
D3 Red LED
IC1 LM741
IC2 LM741 741 PIN CONFIGURATION VR1 and VR2 adjust the point at which the red, yellow and green LEDs are
on or off. For example the
red LED comes on at below
10V, and the green LED at above 12V. The yellow LED is on between these values.
Circuit adjustment:
Turn both presets to ground side (anticlockwise) . Then Gives 10v to this circuit using adjustable power supply and adjust VR2 to yellow led comes on. Again gives 12v to circuit and
adjust VR1 to green led comes on.
