How do we use a multimeter?

01/08/2026

This article is for those who are new to this world. I believe it is important to also create tutorials like this for people who need them. Don't worry, it is very easy to use.

You will see DC and AC, meaning direct current and alternating current. I didn't give detailed examples for each one.
Direct current (DC) is, for example, the current from a battery. It flows in only one direction (DC – Direct Current).
Alternating current (AC) is the type of current that periodically changes direction, like the one from wall outlets (AC – Alternating Current).

Since this is a beginner tutorial, there is no need to talk about frequency.

All multimeters have a similar interface. Mine was more expensive, but you can find multimeters for around 30 lei that do the same job.

Basic formulas (Ohm's Law):

V = I × R
I = V / R
R = V / I

where:

V = voltage (V)
I = current (A)
R = resistance (Ω)

So, let's get started!

1. Measuring Voltage (V)

To measure voltage, switch the multimeter to the "V" mode (for Volt).

For direct current, use DC.
For alternating current, use AC.

Place the probes on the contacts of the power source, and the voltage should appear on the screen.

So, what does voltage do? Voltage measures the electric pressure that pushes electrons through a circuit.

2. Measuring Electrical Resistance (Ω)

To measure electrical resistance, select the "Ω" mode (for ohm) on your multimeter.
Place the probes on the component whose resistance you want to measure, and the value in ohms will appear on the screen.

There is also another method using the color code. You can calculate resistances, power, and current online on a website created by Chiper Ștefan.

Website link: here
Resistance calculator link: here

So, what does the ohm measure? Ohms measure electrical resistance—how much a material resists the flow of electric current.

3.Electrical conductivity

This function helps us check if current flows from one point to another. For example, it allows us to see if a cable is broken.

Place the probes on the circuit, cable, wire, or any conductor. If current flows, the multimeter should beep. If it does not beep, no current is passing through, which probably means the component is damaged.

So, what is electrical conductivity? Electrical conductivity is the property of a material that allows electric current to pass through it. The higher the conductivity of a material, the easier it is for current to flow.

4. Diode Mode

This mode is used to test components that operate at low voltage, such as LEDs, buzzers, etc. It looks like this: ─|>|─.

The multimeter will supply a small voltage to the component, and the screen will display the voltage.

5. Thermometer Mode

This mode is not available on all multimeters, but it is quite useful. It is generally used to check how hot a component or object gets.

Here it's very simple: just connect the thermometer and select °C or °F.

6. Measuring Electric Current

Another unit of measurement is the ampere, which is very important and well-known.

To measure current, select "A" (Ampere) and choose DC or AC, just like when measuring voltage.

So, what does the ampere measure? It measures electric current—how much electricity flows through a circuit per second.