How do I measure voltage?

How do you measure voltage? If you use a multimeter then anyone can easily measure the

▪ Summary

Since voltage is not visible to the naked eye, it is not possible to confirm "how much voltage is flowing through the circuit at a glance". However, the circuits of electronic devices have a set voltage for normal operation, and if the voltage is too high, it may lead to product malfunction or personal injury.

In addition, a voltage that is too low will not work, so when an electronic device has a problem, it is important to check that the voltage is appropriate. Here, we will detail how to use a multimeter when measuring voltage, and what to look for when using it.

■ Voltage measurements require a multimeter

No matter what you want to measure, you need a measuring instrument. For example, "a ruler for length", "a scale for weight", "a clock for time", etc. A measuring instrument is needed to measure things accurately. Therefore, what measuring instrument to use varies according to the "object of measurement".

The same applies to voltage measurements. In particular, because voltage is something that cannot be seen or touched, it cannot be roughly estimated in contrast to the measurement of substances. Therefore, the measurement of voltage requires the use of a multimeter. And the purpose of using a multimeter is as follows.

- safety check

- Quality testing

- Predictions based on measured values

- troubleshooting

- Confirmation of applicability

The condition of electrical equipment can be thoroughly checked by measuring voltage with a multimeter.

■ Types of multimeters

Although they are all called multimeters, there are actually various different types. The main multimeter types are explained in detail below.

Analog multimeter

An analog multimeter is a measuring instrument that makes sense by swinging the pointer on a scale. It has the advantage of being "easy to use" because of the simplicity of the items that can be measured. On the other hand, it has the disadvantage of high wear and tear.

Digital multimeter

A digital multimeter is a measuring instrument that displays measurement results in digital form and is capable of accurately confirming values. Many of them have multiple functions that allow multifunctional measurements, conduction checks, diode checks, etc. that are difficult to achieve with analog multimeters. Some models can transmit measurement data to a computer. Still another feature is the low loss of the instrument. Also, there are different types of digital multimeters depending on the rectification method.

In the "Average Rectification Method", the input waveform is treated as a sine wave, converted, and the measurement result displayed. Note that in this case, if the waveform is distorted, the measurement error becomes large. On the other hand, in the "True RMS method", a waveform containing harmonic components is converted and displayed, so that a value with a small measurement error can be displayed.

The True RMS method calculates and displays waveforms containing harmonic components using the root-mean-square formula.

There are also other types that are subdivided by function, such as high-end models with or without current measurement terminals, and simple models with various measurement items. High-end models enable high-precision measurements in a variety of applications, but they are also more expensive, so it is advisable to purchase a product that suits your measurement purposes.

■ How to use a multimeter

Here we will outline a series of steps for measuring voltage using an analog or digital multimeter.

・Selection of measurement items

Many analog and digital multimeters are often multifunction multimeters with multiple measurements. In this case, first turn the knob to the voltage measurement position. In many cases, the measurement can be changed by turning the knob. Voltage measurement is the item labeled "Voltage" or the unit of voltage "V". In addition, if you make a zero adjustment before measurement, you will be able to measure more accurately.

・Measurement with a test pen

There are terminals for inserting the test pens, so insert the red and black meter sticks separately. The terminals of the black meter stick are universal, but the terminals of the red meter stick vary depending on the measurement item, so be sure to insert them into the terminals used for voltage measurement for voltage measurement.

Read the value.

When measuring DC, the red color of the test pen is connected to the positive terminal and the black color is connected to the negative terminal. When measuring AC, there is no positive or negative relationship. If you want to measure the voltage, put the test pens on both ends of the test object so that you can measure the value. If it is analog type, look at the scale and pointer position to read the value, if it is digital type, look at the number to read the value.

Voltage measurement allows you to select the measurement range. If you cannot predict the voltage to be measured, start with a large range and gradually decrease it. In the case of digital multimeters, some models with automatic range switching are more convenient.

■ Points to note for voltage measurement

There are several considerations when using a multimeter to measure voltage.

・Remove the test lead when changing the range.

If you want to change the range, remove the test meter pen from the measuring circuit before making the change. There is a risk of malfunction if the range is switched with the test pens connected.

Do not touch anything unnecessary while the meter is in contact with the pen.

When the meter pen is contacted, only the target part is contacted. Inadvertent contact with other parts may result in not only tester malfunction, but also measured malfunction.

■ Recommended voltage measurements with a multimeter

In order to confirm the safety and quality of electronic equipment, it is sometimes necessary to measure voltage. A multimeter is used to measure voltage, and multimeters with various functions such as analog type and digital type are easy to use. Please refer to the usage methods described in this article and select the multimeter suitable for your measurement purpose to measure voltage.