What is a Multimeter: Easiest Guide Available

Multimeter Image

We all have listened about multimeters (digital or analog) once or more. It is the most basic and important measurement tool used in any physics lab or workshop. As it is used to measure many electrical properties of other industrial tools. Here we are going to give an overview of its types, and what all it can measure.

What is a Multimeter: Definition

According to Wikipedia,” A multimeter or a multitester, also known as a VOM, is an electronic measuring instrument that combines several measurement functions in one unit.”

Now let’s understand it with a broad definition.

A Multimeter is an easy to handle tool used as a tester to measure electricity, Ac & Dc voltage, current, resistance, and other parameters typically over several ranges of values. It is also known as Volt-ohm-meter because of its voltage and current measuring property.

Today multimeters with a lot of functions are available in the market depending upon the requirement of the people. It is mostly used by peoples dealing in electricity, auto, laboratories, and other power sources and circuit required industries. For selecting different electrical parameters for measurement most of the multimeters have a rotary switch or a dial on its front panel.

Related articles to read:

  1. Working principle of multimeter
  2. How multimeter works

Multimeter types:

There are 2 types of Multimeter; Analog and Digital. You can use any one of them for measurement as per your comfort level and requirements. Basic description of these 2 are given below:

(i) Analog Multimeter

Analog Multimeter Image

An Analog multimeter is also known as a moving coil instrument. It uses a microammeter to measure the value of current, voltage, etc and a needle as a pointer. The display usually relies on a microammeter whose pointer moves over a scale calibrated for all the different measurements.
One benefit of these is while detecting slow voltage changes due to the continuously moving needle for even slight change in the input value.
You can easily measure different quantities by changing the switch setting or range on the device itself with the use of various detachable probes.

(ii) Digital Multimeter

Digital Multimeter image

A Digital Multimeter is the most usable test equipment in the electronic industries. It uses a liquid crystal display screen and a frequency selector switch that gives a straight forward output in a decimal form.

To provide better accuracy, digital multimeter obtains several samples of the signal during a short period of time and it also offers automatic ranging feature so that the user does not have to select the measurement manually.

Nowadays we prefer Digital multimeter more than Analog multimeter because of its accuracy, faster response, LCD display screen, etc.

Analog vs Digital Multimeter

Most of the time we are confused which one to buy out of these two. So here we provide its comparison table below to clear your confusion. It will help you in selecting a good one for your work.

Analog multimeter Digital multimeter
It is less costly due to simple construction and no power supply required It is far more costly due to complicated construction and requires power supply
Into these Range has been adjusted by the user Into these multimeters range is adjusted automatically
In these multimeters visual indication of changes in the reading is not good due to effect of damping torque In these multimeters visual indication of changes in the reading is excellent
These are accurate but not as much due to magnetic effect in the coil being degraded after usage These are very much accurate multimeters
It gives the output as a reading on a scale against a pointer It gives output in numerical form displayed on the LCD
These multimeters are calibrated manually These multimeters are calibrated automatically before every measurement
Range of measurement is good Range of measurement is excellent
It is not easy to handle It is easy to handle i.e. can be used even by untrained person

Basic Functions: What properties it can measure

It is a basic question that arises in mind that what it can measure and how it helps us to solve our problems. So we are writing all of them below. Once you get these points, you can choose which one to buy from our list of best multimeters companies.

Well, many electrical properties can be measured. Advance multimeters from companies like Fluke come with additional features that make them “all in one” type.

  1. Voltages (Ac & Dc )
  2. Current (Ac & Dc ),
  3. Resistance
  4. Frequency
  5. Temperature
  6. Capacitance
  7. Continuity
  8. Diode check
  9. Conductance
  10. Decibels
  11. Inductance

During the continuity check, it results in a “beep sound” when two circuits are electrically connected. The beep sound ensures that the circuit is connected correctly without any loose connections and prevent short circuits. During Diode check, it ensures the direction of flow of current in the circuit.

Basic Electrical Terms:

Before doing any measurement, it is recommended to have some knowledge of basic terms. We explain some terms below have a look over it.

(i) Voltage: According to Ohm’s law voltage is defined as the product of current and resistance. It tells us how much electricity is sent through the circuit. Higher the voltage higher the electricity was sent. Its unit is Volts and is expressed as V.

(ii) Resistance: It basically obstructs the path of flow of the current. More resistance will results in lesser current flow through the circuit. Its unit is ohms and is expressed as Ω.

(iii) Current: It indicates how much electricity flows inside the circuit. It is dependent on the resistance value because both are inversely proportional to each other. Its unit is Ampere and is expressed as A.

(iv) Alternating current voltage: This type of electricity generally flows in residential areas or in our houses. Its frequency is 50 Hz. If you need to measure alternating current in a circuit, different multimeters have different symbols to measure it. Most used symbols are “ACA” and “ACV,” or “A” and “V” with a squiggly line (~) next to or above them.

(v) Direct current voltage: This type of electricity generally flows in auto and household batteries like AA or AAA batteries. Its frequency is 0 Hz. Different multimeters have different symbols for measuring direct current. “DCA” and “DCV,” or “A” and “V” with a straight bar above or next to them are generally used.

(vi) Capacitance: It is a passive device used to store an electric charge. Its unit is Farad and expressed as F.

Precautions to take

We use Analog or Digital multimeter for the measurement of AC voltage, AC current, DC voltage, DC current, Resistance, etc. By using integrated circuit technology provide we can also add additional measurement capabilities like Capacitance, Temperature, Frequency, etc as explained in the above heading.
To make measurements more accurate without any loss or damage we have to follow a number of initial steps & precautions because old people say prevention is better than cure.
(i) Be sure probes are in good condition: If probes are not in good condition then there are more chances of inaccurate readings. During high voltage measurement, if probes are broken or cracked, it will cause more risk of injury to the user.

(ii) Check Battery Regularly: Batteries are the main part of any electronic equipment because without this you cannot provide power to the device.
If batteries are left in locally for long periods they can leak and damage the contacts. As the contents of the battery are corrosive. So, it is recommended to check the battery regularly and replace immediately if required.

(iii) After use always return the meter to high voltage setting: To prevent the possibility of accidental damage by the meter being set to a current or low voltage range, it is always recommended to set the meter to high voltage after use even if there is an off button.
Some meters are auto-ranging which automatically set current & voltages as per need, but some are manually operated that’s why we have to take care of this factor.
Hope this article will help you. We always welcome your suggestions.

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