Car battery tester circuit

2016-01-21 04:27  
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This article shows that the car battery tester circuit. This circuit uses the LM3914  IC, before you read this diagram can find out the IC. When the test button is pressed, the car battery voltage is fed to a high-impedance voltage divider. His aim is to 12 v, 1,25 v (or low value lower value). This solution is compared to an internal voltage regulator set 12 v sample voltage is input to the internal voltage divider simply because it can not regulate the voltage drop at 12 v low (linear regulators only step down). Simple wiring is not adjusted, the regulator provides a stable 1,25 v is fed into the precision internal resistor cascade generates an internal voltage comparator sample. Anyway, the default settings allow you to measure the voltage from 8 to 12 v but you can measure even from 0 v to 12 v Set the offset trim to 0 (but I think your car will not start 9 volts). There is a smoothing capacitor (4700 uf 16 v) which is used to adsorb EMF noise produced in the ignition coil if you measure the battery in the engine work. Diesel engines do not need it, but I'm not sure. If you like more than a dot plot just off the overhead bar 9 of the IC (mode) of power.
The first voltage comparator 8 V 0833 V corresponding
The second voltage comparator: 0875 V corresponding 8,4 V · · · · · ·
Finally comparator voltage: 1,25 V to 12 V correspond.

 

 

Battery tester

 


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