How are digital multimeters different from analog multimeters?
A multimeter is an electrical measuring instrument used to measure electrical parameters such as voltage, current, and resistance. Multimeters are not always the same, and different types of multimeter have different dimensions, accuracy, accuracy, and measurement parameters. Multimeters are mainly used by electricians, engineering students, and amateurs to troubleshoot electrical equipment and circuits. There are two main types of multimeter, namely analog multimeter and digital multimeter.
Analog multimeter
Analog multimeter is the oldest multimeter. It has a needle that rotates along the scale, but it is difficult to read. The advantage is that it is cheap and sensitive. Analog multimeter is more sensitive than digital multimeter, and can even sense small changes in readings.
The analog multimeter is made of a coil placed between two permanent magnets, with a needle placed at the top of the coil. When current passes through the coil, it generates a magnetic field that interacts with the permanent magnet magnetic field, thereby rotating. As the coil rotates, the pointer will move along the scale. The rotation angle of the coil depends on the amount of current flowing through the coil. Therefore, an analog multimeter, also known as a galvanometer, has a very small resistance and is therefore more sensitive than a digital multimeter. But it is important to avoid full scale deflection (FSD). When the current exceeds the range of coil deflection, it begins to burn out the coil, causing damage to the instrument.
Digital multimeter
A digital multimeter refers to an instrument that can measure various parameters and display them on an LCD screen. Unlike analog multimeters, digital multimeters are displayed in a numerical calculation format, making it easier to read measurement results. But the other side of this advantage is that the analog multimeter can display readings without any calculations, thus having a fast response time.
The digital multimeter has an LCD, a rotating dial, and multiple ports. The dial includes an internal circuit connected by a concentric ring. The dial knob is used to activate the circuit for specific measurements. A digital multimeter is embedded with a microprocessor to calculate readings. However, the input voltage or current is in analog form. Therefore, an ADC (analog-to-digital converter) is included to convert the reading and display it on the LCD screen. Unlike the pointer scale on an analog multimeter, the LCD makes the measurement results easy to read. In addition, the digital multimeter has overload protection when the measurement exceeds the range.
