The Basics Of Multimeters And Battery Testing

What is a multimeter and how to use it

Multimeters are devices used for measuring different aspects and performance of electrical circuits or components such as transistors, capacitors, diodes, and batteries. Characteristics that can be measured using a multimeter include voltage, current, and resistance.

How it works

A multimeter has two sets of leads colored black and red. These leads are attached to the component which needs to be tested. A digital or an analog screen on the multimeter then displays the readings that are generated. An adjustable knob allows you to set the multimeter on the characteristic being measured.

Measuring Resistance (Ω)

In order to test the resistance of a particular circuit, you start by attaching the resistor leads to the test leads. The multimeter will then have to be dialed to the resistance range in which the resistor fits.

When reading the value on the screen keep in mind that a value of 1 will mean that you guessed too low. Readjust the dial to the next range until a valid reading is obtained. In case you have reached the lowest range and the value on the multimeter does not change, the circuit has zero resistance.

Measuring Voltage (V)

When testing battery voltage, connect the red lead of the multimeter to the battery’s positive terminal and the black lead to the ground or negative terminal. Then turn the to the voltage range that is expected.

For accurate battery voltage readings, batteries must remain idle for a minimum of 6 hours. You can check the state of charge of your battery in Table 1. If the registered readings show a percentage of charge between 0% and 70% charge the battery. If the readings are below the values in Table 1 your battery has a dead cell or has been left in a state of discharge for too long.

Table 1

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