multimeter with a resistor and probes in the background

How to use a Digital Multimeter for Beginners

Today, instead of doing an arduino/microcontroller tutorial, we look how to use a multimeter which is an essential piece of equipment for hobbyists and makers when building electronics projects.

The basic function of the multimeter is to measure voltage, current and resistance which is the three components of ohm’s law.

Here we look at how to use a multimeter for the most common measurements which is voltage and resistance. We haven’t forgotten about current, but it’s generally not measured as much as voltage and resistance when putting together our electronics projects.

 

Manual vs Autoranging Multimeter

This meter we are using is called an autoranging multimeter. Autoranging means exactly that, the range on a setting for example voltage adjusts as required. On older multimeters you needed to set the range of the voltage you want to measure, so for example if you want to measure 5V DC you need to move the dial to the voltage range that covers 5V DC. A good meter would have about 4 voltage ranges.

The issue with having several voltage ranges is if you were not careful, you could measure a high voltage on a low voltage range and destroy the meter electronics. Thankfully we now have autoranging meters that selects the range for you automatically making the process of measuring voltage, current and resistance much easier and safer.

Measuring DC Voltage with a Digital Multimeter

 

measuring a battery voltage

 

Before we turn the meter on we need to connect the black probe to the common input of the meter and the red probe to the voltage input of the meter. Then we turn the dial to volts DC then place the probe ends across the component we are measuring, in this case it’s a 1.5V carbon battery. It does not matter what why around probes touche the component’s wires as the meter will determine the polarity of the voltage and should display a positive or negative voltage. If the voltage reads negative, it means the probes should be swapped around to give a positive reading.

 

Measuring Resistance with a Digital Multimeter

 

measuring a resistor

 

Like measuring voltage we need to turn the dial on the meter to the resistance setting. The probes needs to be across the resistor legs. The polarity does not matter in resistance, so the red and black probes can be used either side of the resistor. An important note to remember, that resistors can not be in circuit when being measured otherwise you may end up with a false reading due to the connected circuit interfering with the measurement.

 

Conclusion

As we’ve just seen a multimeter is very useful to the electronics hobbyist. When required, we can measure the basic voltage, resistance and current and with more sophisticated multimeters you can even measure frequency, inductance, capacitance and some even have built in transistors testers.

I hope this tutorial was useful to you.

Thanks for reading this tutorial !