Print Friendly and PDF

How to Use a Digital Multimeter and Why

A digital multimeter is preferred because it is more accurate in giving data with decimals and it can also measure capacitance and frequency.





A multimeter is a tool that helps to measure electricity in terms of voltage, current, and resistance. Voltage is the measure of how strong the electricity is moving in a circuit and is measured using volts. Current is the amount of electricity that is flowing through the circuit and is measured using amperes. Resistance is the measure of how hard it is for electricity to flow and is measured using ohms.

Discovered in the 1920s, multimeters have been used to diagnose electrical problems. There are two types of multimeters, the analog, and digital types. The digital type is preferred because it is more accurate in giving data with decimals and it can also measure capacitance and frequency.


The Advantages and Drawbacks

The advantage of the digital multimeter over the analog type is that it is more accurate than the analog multimeter because they have a numerical display rather than the pointer in the analog type. This, therefore, helps to minimize errors in data reading and interpretation. The digital multimeters have no shock failures because their displays do not have moving parts. They have a faster reading speed and, therefore, increase convenience.

You also do not have to adjust the digital multimeter to zero as you would need to when using the analog type. As you see on, the digital multimeter has an auto-polarity function which prevents you from connecting it to the circuit that has the wrong polarity. They also have an auto-ranging function which prevents the damage that would happen if the wrong range is used.

Some of the drawbacks of digital multimeters are that they are more expensive than the analog type. They are also unable to read fluctuations in the measurements. If the voltage has exceeded the limit which the digital multimeters can work at, they become damaged. They also depend on batteries or external power to function and can, therefore, fail if these are unavailable. Overheating can damage them and give wrong readings.


How Does the Digital Multimeter Work?

The multimeter has four parts -- the display, the selection knob, the ports, and the probes. The display is the area where you read the measurements from. The display normally shows 4 digits and can display decimals and negative signs. The selection knob helps you to choose what you want to measure, whether it is the current, the voltage, or the resistance.

The probes are plugged into the ports. The COM port is where the black probe is inserted and is used for earthing. The red probe is attached to any other port, depending on what you are measuring. The red and the black probes have no difference except the color. A banana plug on the probes enables them to be connected to the multimeter.

There are two types of current that you can measure, the direct (DC) or the alternating current (AC). Direct current, which flows in one direction, is the type of current in the AA and AAA batteries, while the alternating current is the type that changes direction multiple times in a second and is found in the wall outlets.



While measuring the voltage, set the mode on the straight line for the DC. For the AC, use the one on the wavy line. Connect the red port to the port that is marked with a V on the positive side, which is the direction where the current is flowing from. The COM probe should be connected on the other side. Ensure that you have placed the probes alongside the leads on where you are measuring the voltage so that they are in parallel. You can then read the measurements from the display.

When measuring the resistance, ensure that the red probe is in the port for resistance. Connect the probes to the resistor leads and read the results. To measure the current, the multimeter should be in series with the red probe on the component and the black probe next to it. To check for continuity, connect the probes to tips of wires. If there is continuity, you will hear a continuous sound, but in the lack of continuity, no sound is produced.


Why Should You Learn to Use a Digital Multimeter?

When you learn to use a multimeter, you can test your batteries. When measuring the voltage, a new battery will have a voltage that exceeds that which it's rated at. You can also use a multimeter to test the electrical outlets. It also helps you to check if your wall switch is working. The digital multimeters will help you measure the temperature of your appliances and also to test extension cords.

You should be careful when handling a multimeter by placing your hands on the plastic and rubber parts and avoiding the metal parts that have energy. Use safety glasses to protect yourself in the event of a flash. If you are not experienced in handling electrical appliances, use the system that does not have live electricity to avoid electrical shock and burns. Watch out for overheating and damage of the multimeter as it can give you incorrect readings.

Digital multimeters measure the electrical voltage, current, resistance, capacitance, and frequency and will help you to text batteries, switches, and extension cables as well as reading the temperature of your devices. You should familiarize yourself with the components of a multimeter and how to use it.



back to top