# 1.5 volt battery tester circuit using LM324

This fine 1.5V battery checker Can measure the voltage of the 1.5V battery AA or AAA. As decimal point. Easy to use by LEDs display, accurate, because the IC-LM324 is a voltage check. Measured with a battery of any kind, whether plain battery or recharge battery(1.2V).

How does it work.
The principle of circuit as show in block diagram Figure 1. When bring the battery that requite test the voltage in this circuit. The circuit will get voltage to compare with voltage internal the circuit. Which come from the battery 9 volts, then display with LED, If the battery still has a lot of power. The LED will glow as voltage of battery that testing.

Figure 1 The block diagram of the 1.5 volt battery tester circuit

We see main principle successfully. Then see serves each components as See in Figure 2. The begin with Dideo-D1 act as protector when we connect the battery that Wrong terminal. The capacitor-C1 and C2 serves to increase to stable to the circuit. The resistor-R1, LED1, The pontentiomer-VR1 and R4 to R11 serves to feed the reference voltage to IC1 and IC2, To compare with voltage of the battery that be tested at pin 12,3,5 and 10 with reference voltage at pin 13,2,6 and 9 of both ICs. Which combined with all eight series.

Figure 2 the circuit of the 1.5 volt battery tester using LM324

Figure 3 The Single-sided PCB layout

Then to display with LED2 to LED9 by has R12 to R19 are limit current to all 8 LEDs display.

The IC2/4 is voltage meter (the compare voltage circuit) that have lowest about 0.9 volts. If voltage of the battery have level lower than 0.9 volts, just a little also will cause the LED9 glow. The check section of the remaining seven series also is set the voltage out already. The battery that get to check have voltage at which LED that will be lightness. The diode-D2 and resistor-R2 serves as load of battery is tested.

By normal battery(good) that we use will have voltage about 1.6 to 1.4 volts. Unless The battery can be recharged will has voltage about 1.2 volts. If lower this will must to recharge now.

How to builds
Starting from create The PCB as Figure 3. This project would have trouble doing this. That requires little skill. However, it is not beyond the capabilities of your possibilities.

Then buy other components on listed below. and How to assemble circuits on PCB in Figure 4 as components layout, By Starting from a low end device before as Resistors then respectively the high up such as the potentiometer, Capacitors, Socket IC, And LEDs is soldered directly onto the PCB attached to the PCB as possible. When soldering equipment and a complete line of IC and then plug it into the final.

The test is very simple, just put 9 volts Battery for use as a reference voltage and a small size battery 1.5V AA To put in place a fully tested. The LED displays the voltage of the battery. But if LED does not display to sorry, You assemble the circuit. But do not panic. You can verify the authenticity as Figure 3. Check the soldering, wiring because of the slight. We overlooked. Cause the circuit does not work.

After modifying until finished, Then the tune. By use a new 1.5V battery put to the test. Then adjust VR1 until LED3 display at 1.5V glow I just finished customizing. And ready to use.

Figure 4 the components layout of this projects.

The component list
IC1,IC2____LM324___Quad/ 1MHz/ Operational Amplifiers for Commercial/ Industrial/ and Military Applications____= 2 pcs.
D1,D2______1N4002____ 100V 1A Diodes_____= 2 pcs.
C1_______0.1uF 50V_____Ceramic Capacitors__= 1 pcs.
C2_____0.001uF 50V_______”_______”______= 1 pcs.
Resistors 1/4W 5%
R1,R4-R10___1K_____________= 8 pcs.
R2________20 ohms_________= 1 pcs.
R3_______100K_____________= 1 pcs.
R11_______8.2K_____________= 1 pcs.
R12-R19___100 ohms__________= 8 pcs.
LED1-LED9___LED as you like___= 9 pcs.
VR1___4.7K potentiometer_____= 1 pcs.
Socket IC 14 leg_____________= 2 pcs.
Battery holder AA size________ = 1 pcs.