Digital and analog multimeters are both used for the express purpose of testing and measuring a number of different electrical quantities including the likes of voltage in volts, current in amperes, and resistance in ohms. However, there are a number of notable differences between digital and analog multimeters, with the former coming with some extra features as well the ability for the measurement of a wider array of electrical quantities.
In comparison to the digital multimeter, the analog multimeter is actually a much simpler device that can be used to measure basic electrical quantities such as currents, voltages, and AC and DC resistance.
Also sometimes referred to as an AVO (Ampere, Voltage and Ohms) Meter, an analog multimeter has within it a permanent magnet moving coil known as a Galvanometer. This is linked to the pivot on a pointer, with trimmers (a combination of resistors) used for the measuring of the current within. The way the pointer deflects is an indication of the measuring quantities value that the screen prints.
The digital multimeter is a much more complex device than an analog multimeter, being a complicated mixture of analog to digital convertor, comparators, logic controllers, digital displayers, encoders and so forth.
There are a number of advantages that a digital multimeter possesses over an analog multimeter because of the inclusion of some special features that are designed to measure further electrical quantities. Digital multimeters are utilised for the calculation of electric current voltage, capacitance, impedance, resistance, inductance etc.
Perhaps the biggest advantage that a digital multimeter has over an analog multimeter is its ability for use with the testing and checking of different electronic devices and components for the purpose of determining their usefulness and whether or not they need to be replaced.
One example of this is that a digital multimeter can be used to check a capacitor, a diode, a relay, and different transistor types, to find the value of a burnt resistor and for the performing of a continuity test. Digital multimeters are also much simpler to use in comparison to analog multimeters and deliver much more accurate results.
The major differences
Analog multimeters can only use a limited number of electrical quantities like resistance, current and voltage, while digital multimeters can measure those as well as many more such as capacitance, transistors and diode values and can also be used on a greater number of electronic devices.
The readings taken by an analog multimeter are shown on a printed value scale that is set against a moving pointer, while the readings taken by a digital multimeter are shown on a digital display as numerical values. Analog multimeters need to be manually calibrated, while digital multimeters are calibrated automatically.
Erroneous pointer readings and parallax mistakes, where the measurement is misinterpreted due to the pointer being viewed from the wrong angle, make the analog multimeter less accurate than the digital multimeter. Today most professionals prefer to make use of a digital multimeter.