Multimeters and voltmeters may seem the same to any other person but to an electrician or electrical engineer. These two measuring devices are different in many ways.
But as their names suggest, a voltmeter measures only voltage. On the other hand, a multimeter can measure more than one electrical parameter, including voltage, current, resistance, capacitance, and frequency. Some also have a temperature probe or sensor for measuring ambient temperature.
Continue reading as we present all differences between the voltmeter and multimeter. This article focuses on multimeter vs. voltmeter, outlining all distinguishing features and functions.
Multimeter Vs. Voltmeter: What Are They?
Multimeters and voltmeters are electrical measuring instruments. But before we get into their differences, let’s briefly define them and state the different types.
What is A Voltmeter?
As the name implies, a voltmeter is an electrical device that measures voltage. Voltage is the potential difference between two nodes in an electrical circuit, and its unit is the volt (V). Once you connect the voltmeter probes at two different nodes, the potential difference or voltage is displayed on the unit.
Some voltmeters are designed to measure voltages only on direct current (DC) circuits. But others can measure voltages on both DC and alternating current (AC) circuits.
Types of Voltmeters
A voltmeter is either an analog or digital device. That depends on how the voltage reading is displayed or the operating principle of the meter.
Analog Voltmeter: These voltage-measuring devices display reading using a deflecting handle and a scale. The person performing the measurements is responsible for interpreting the scale and recording the correct reading.
The needle on the analog voltmeter deflects or responds to the slightest change in voltage across the probes.
Digital Voltmeter: These voltage measuring devices often have an LCD screen or use LEDs to show voltage readings. They don’t have a scale or pointer, but you may still need to change the range settings on the meter to get accurate results or avoid OL on the screen. This means over the limit. You will often see it if you are using a lower range or the voltage on the circuit is more than what the voltmeter was designed to handle.
What is A Multimeter?
Like a voltmeter, you can use a multimeter to measure the potential difference between two nodes in an electrical circuit. However, they can also measure resistance, current, and capacitance. That is why multimeters are sometimes called VOMs, which stand for Voltage-Ohm-Amperes. But some of these devices can also measure inductance, capacitance, frequency, temperature, humidity, and acidity.
Most multimeters can measure DC and AC parameters in an electrical circuit. They often feature a rotary button on the interface that allows you to change what you want to measure. Some are auto-range, but others require you to manually adjust the knob or press a button to set the measurement limits.
Types of Multimeters
Like voltmeters, there exist analog and digital multimeters.
Analog Multimeters: An analog multimeter operates the same way as analog voltmeters. The needle deflects to either direction depending on the voltage, resistance, or current measured. However, these devices are rare to come by these days because of their limitations.
Digital Multimeters: Digital multimeters (DMMS) use an LCD screen to show the measured value and other information, such as the range and parameter to be measured. These are more advanced instruments with multiple functions.
Digital multimeters are user-friendly, lighter, versatile, and more accurate. The construction typically consists of the main body, display unit, buttons, rotary switch or knob, and input jacks or probes.
Comparison Table between Multimeter and Voltmeter
|Definition||A multimeter is a multi-purpose measuring instrument for measuring different electrical parameters such as voltage, current, resistance, etc.||A voltmeter is a single-use measuring device for determining the potential difference between two noses in an electric circuit (voltage).|
|Circuit connection||How a multimeter is connected to a circuit depends on the parameter to be measured. It is connected in series with the electrical circuit for measuring current and in parallel if measuring voltage.
A multimeter can also be connected across components. That is the case when testing or measuring capacitance, inductance, and resistance.
|The voltmeter is always connected in parallel with the circuit whose voltage is to be measured.|
|Internal resistance||The internal resistance of a multimeter is negligible when measuring current in a circuit and a larger value when measuring voltage. In other words, the internal resistance is set according to the quantity to be measured.||By design, the internal resistance of a voltmeter is close to infinity to prevent current from flowing through it for accurate voltage measurement.|
|AC and DC Measurement||All multimeters can measure both AC and DC electrical quantities.||A voltmeter can be designed to measure either AC or DC voltage, as a device that can measure both is rare.|
|Construction||Multimeters are highly advanced measuring instruments with complex designs to combine all functions in one unit.||A voltmeter is simple in design because it performs only one function – measuring voltage.|
|Power requirement||A digital multimeter requires an internal power source to accurately measure electrical quantities.||A voltmeter, especially the analog type, does not require a power source to measure voltage in an electrical circuit.|
|Physical Size||A multimeter tends to be big in size to create room for all the circuit components required to perform multiple functions.||Relatively small in size because it requires fewer components to construct.|
|Scale||A multimeter is automatically scaled or calibrated to measure various electrical quantities, depending on what the user wants to measure.||A voltmeter is only calibrated for measuring potential differences in an electrical circuit. However, you can set the range to measure small or large quantities.|
|Price Tag||The many functions of a multimeter come at a price. They are relatively more expensive than voltmeters.||A voltmeter is relatively cheap because it is easy to construct and only measures voltage.|
|Substitution||You can use a multimeter as a voltmeter||You cannot use a voltmeter as a multimeter. It cannot measure other electrical quantities, such as resistance, current, capacitance, inductance, etc.|
|Component Testing||A multimeter can test diodes and transistors or continuity in a circuit.||A voltmeter cannot perform these tests.|
Multimeter Vs. Voltmeter: Conclusion
A multimeter is a multi-purpose and versatile tool for every electrician or electronic engineer. It is the best choice if you want an all-in-one instrument for measuring electrical quantities or additional functions, such as measuring temperature, humidity, and acidity. You only need to use the appropriate probe and adjust the settings on the device.
Regarding voltage measurements, you can choose either a voltmeter or a multimeter. Both can offer the accuracy needed for the application. However, that can depend on the brand or model of the device you have. As a result, always consider quality products from reputable brands.