Multimeter devices are instruments that allow performing almost all the operations carried out by several devices such as an ammeter, voltmeter, and ohmmeter, all in one device. Among these devices, the ammeter measures current intensity, the voltmeter measures voltage, and the ohmmeter measures resistance. However, the multimeter stands out by being able to perform the measurements done by these three devices on its own.
Besides these measurements, multimeter devices can be used to measure transistor gain, frequency size, temperature, diodes, and capacitor capacitances. There are two types of multimeters: analog multimeters and digital multimeters.
Analog Multimeters
Analog multimeter devices are no longer widely used today due to advanced technology. These scale multimeters allow easier observation of voltage variations. However, the likelihood of these scale multimeters malfunctioning is much higher compared to digital ones.
Digital Multimeters
Digital multimeter devices are instruments that can measure with an LCD screen and display the unit value. There is a wide variety of multimeters on the market, and this diversity is also reflected in prices. The quality, accuracy, and durability of the instrument determine large price differences between devices.
How to Use a Multimeter?
Digital multimeters have a knob for selecting ranges. With this knob, the size to be measured or the corresponding value for the measurement is chosen. A good example is selecting the 40 Volt DC (Direct Current) range, which means that the measured voltage will not exceed 40 Volts DC. Therefore, choosing the correct range is very important. If you want to measure a higher voltage, you will not get an accurate result if the selected range is lower. Due to the DC selection, alternating current (AC) measurement will not be possible. Some multimeters have a button to select between DC/AC. Therefore, if the exact value of the quantity to be measured is not known, it is correct to start measuring by selecting the highest range. Some multimeters automatically adjust the range. In these cases, the user only needs to decide whether the voltage is DC or AC.
Multimeters have two probes. The black probe should be inserted into the COM socket. The COM socket represents the common terminal. The red probe should be inserted into the correct socket depending on the voltage to be measured. A indicates current, V voltage, and Ω resistance.
Parameters to Consider When Choosing a Multimeter
Sensitivity
When making sensitive measurements, the person measuring must calculate the internal resistance of the measuring device in advance. This characteristic is called sensitivity. The class of the measuring device is indicated on the label in units of Ω/V.
Count
Count indicates the maximum value that the LCD screen of a multimeter can display. The higher this value, the more precise the measurement. A good example is the comparison between a multimeter with 7,000 count and one with 50,000 count; when measuring 500 volts, the 7,000 count multimeter will display 500.0 Volts, meaning one decimal place. The 50,000 count multimeter will display 500.00 V, meaning two decimal places, thus offering ten times greater accuracy.
Resolution
It is the most precise measurement value that a multimeter can perform.
Accuracy
Refers to how close the value displayed on the screen is to the actual value. According to current standards, the accuracy of the measuring instrument must be certified through calibration certificates. Regardless of the functions, technology, or price of the device, if the accuracy is low, its value and importance decrease.
Durability
Durability is an important parameter for a multimeter. Using a device resistant to harsh conditions is an advantage. High temperatures, humidity, and dust negatively affect both the accuracy of the measurement and the device’s lifespan.
Speed
A fast response time at the moment of measurement is very important.
Calibration
It is very important that the device has a calibration certificate.
