Get to know AVOmeter, Functions, Parts, Types, How it Works, and How to Use it

An AVOmeter, also known as a multimeter, is a crucial measuring instrument in the field of electrical engineering and electronics. It is used to measure three key electrical parameters: current (ampere), voltage (volt), and resistance (ohm).

Below is a discussion about the definition, functions, parts, types, working principles, and how to use an AVOmeter. Let’s dive in!

Definition of AVOmeter

An AVOmeter is an essential tool in electrical and electronic engineering used to measure current, voltage, and resistance in a circuit. This tool helps technicians diagnose electrical issues, such as voltage drops or excessive current, which are important in the maintenance and repair of electronic equipment and electrical systems.

There are two types of AVOmeters: analog and digital. An analog AVOmeter uses a needle pointer to monitor changes continuously, while a digital AVOmeter offers higher accuracy and ease of reading with numerical displays on an LCD screen. The use of either type depends on the user’s measurement needs.

Functions of AVOmeter

Current Measurement (Ampere)

This tool measures electrical current, which is the flow of electrons passing through a point in the circuit. Measuring current is important in diagnosing whether a circuit is functioning correctly or is overloaded, which could lead to excessive heat and potential damage to electrical components.

Voltage Measurement (Volt)

AVOmeter is also used to measure voltage by determining the electrical potential difference between two points in a circuit. This measurement is important to ensure that the voltage supplied to a device matches the required specifications, preventing damage from either too high or too low voltage.

Resistance Measurement (Ohm)

Another function of the AVOmeter is measuring resistance or electrical impedance in a circuit. This helps determine the condition of components like resistors, ensuring they are functioning properly and not failing, which could disrupt the electrical flow in a circuit.

In addition to being used for residential and electronic installations, the AVOmeter is also commonly used in the maintenance and repair of electronic and automotive equipment, such as checking the voltage of a car battery or the condition of a vehicle’s electrical system.

Parts of an AVOmeter

An AVOmeter consists of several important parts, including:

1. Display Screen

The display screen shows the measurement result. In an analog AVOmeter, it displays a scale with a needle pointer, while in a digital AVOmeter, it shows an LCD screen.

2. Probes

These are cables used to connect the AVOmeter to the circuit being measured.

3. Selector Switch

This part is used to select the type of measurement (voltage, current, or resistance) and the desired measurement range.

4. Zero Adjustment

On an analog AVOmeter, this is used to calibrate the instrument before measurements.

Types of AVOmeter

There are two commonly found types of AVOmeters:

Analog Avometer

The analog AVOmeter uses a needle pointer that moves along the scale to show the measurement result. Users must be careful when reading the results, as the needle's position can be influenced by vibrations or incorrect viewing angles, potentially affecting accuracy. Nevertheless, this tool is useful for monitoring continuous changes in a circuit.

Digital Avometer

A digital AVOmeter displays the measurement results as numbers on an LCD screen, making it easier to read and more accurate than the analog version. With a digital display, users can avoid misinterpretations that often occur with analog scale readings. This type is also usually equipped with additional features, such as data storage and automatic functions, which make measurements easier.

How the AVOmeter Works

The AVOmeter operates by passing electrical current through the circuit being measured and then displaying the measurement result on the screen or scale. When measuring voltage, the AVOmeter is connected in parallel with the circuit to measure the potential difference between two points without affecting the current flow.

In order to measure current, the AVOmeter is connected in series with the circuit, thus that all the current flowing through the circuit also passes through the meter, allowing for an accurate measurement. When measuring resistance, the AVOmeter measures the voltage required to pass a specific current through a resistor, and then calculates the resistance value.

How to Use an AVOmeter

Here are the simple steps to use an AVOmeter:

1. Measuring Current (Ampere)

• Set the selector switch to the ammeter mode (A).
• Connect the AVOmeter in series with the circuit.
• The measurement result will appear on the display.

2. Measuring Voltage (Volt)

• Set the selector switch to the voltmeter mode (V).
• Connect the red probe to the positive terminal and the black probe to the negative terminal of the source or circuit.
• Read the measurement result on the display or scale.

3. Measuring Resistance (Ohm)

• Set the selector switch to the ohmmeter mode (Ω).
• Ensure the circuit is not powered before taking the measurement.
• Connect the probes to both ends of the component being measured.
• Read the resistance value displayed.

Using an AVOmeter requires basic knowledge of electricity and circuits to ensure accurate and safe measurements. With this tool, technicians can easily check and ensure that electrical components are functioning properly.