Multimeter Definition Types and Uses
Multimeters are handy pieces of equipment that come in handy in measuring the electrical parameters of appliances ranging from voltage, current, and resistance. If you ever find yourself in a situation where you need to measure the voltage in an appliance, test the active components of a battery, or design a circuit, multimeters will be the go-to measuring tool. This article deals with what multimeters are, their classification, their principles of operation, and some handy guidelines for choosing and working with the multimeter.
What Is a Multimeter?
For many people, a multimeter, also known as a VOM, or a Volt-Ohm-Milliammeter, is just a measuring device, but there are reasons still we should deem it as an important tool for almost all electrical-related works. These include circuits, conductors, and amplifiers. All of these tasks involve measuring values that can be interpreted only through the use of a multimeter. Measuring purposes can be simplified into three basic divisions which include:
Volt Measurement (Voltmeter): Voltmeter refers to measuring the potential difference between 2 points in a circuit.
Current Measurement (Ammeter): Ammeter’s measurement is done to find the amount of electric charge passing through a circuit.
Resistance Measurement (Ohmmeter): Ohmmeter Measures how much current will pass through a conductive material.
Most meters on the market today are designed with one or several other functions in addition to the above, in particular, the measurement of capacitance, continuity, frequency, temperature, and sometimes transistors.
Types of Multimeters
There are different types of meters depending on the level of practice:
Analog Multimeters
The readings are displayed on a scale by the movement of a needle, this type of measuring device is called an analog multimeter. Some professionals still prefer using these types as the reading is not stepped but continuous as in the case of the digital types of meters. However, they are less reliable and more prone to damage than the digital types.
Digital Multimeters (DMM)
Today’s digital multimeters which are the most commonly used type have the results displayed on the screen. They are also more accurate and easier to operate for novices and experts alike. Autavas is a feature many digital multimeters have, which means the user has to “try” the appropriate level for the measurement.
Clamp Meters
A clamp meter is a kind of multimeter that measures the current flow in a circuit without having to open it. The “clamp” is made to encircle the conductor wire and from there, the reader senses the magnetic field and computes the current running through the wire. This type is suitable for measuring high current & similar applications where the leads cannot be connected directly.
Fluke Multimeters: When it comes to multimeters, USA-based FLUKE is the most sought-after. Most fluke 179 fluke multimeters are well-designed, sturdy, and consistent in their performance. Exhibit high-level features such as True RMS to effectively measure any kind of AC waveforms and a very high level of electrical noise immunity.
Important Key Specifications to Look For
Make sure to select a multimeter that can meet your needs for most essential dimensions, among other things:
Accuracy
The term accuracy can be defined in simpler terms as how evenly the reading on the multimeter and the real value of what is measured. In basic applications, an accuracy level of ±0.5% to ±1.0% would suffice. However, exceptions remain when it comes to more delicate electronic devices or equipment where high accuracy is desired.
Resolution
It is the concept used to portray the minimum incremental increase where a can appreciate a change. It is important because higher resolution means increased accuracy, which is necessary when working on devices with low current or low voltage.
Range
Range refers primarily to the available measurements in Voltage, Current, and resistance The ranges in such devices are also referred to as manual ranging where the user will have to define the range of measurement. There are also auto-range devices that will choose the proper range on your behalf.
True RMS
When measuring AC voltages and currents on non-sinusoidal waveforms, this feature may be necessary because standard measuring devices like multimeters may yield inaccurate readings. True RMS meters provide improved readings for both linear and nonlinear loads.
Input Impedance
The capacity for input impedance must be high on the Analog multimeter because the is not to disturb or disturb the circuit under test. However, this may pose limitations with lower input impedance, especially in performing voltage measurements for high-impedance circuits.
Features and Functions
Throughout the day, there are basic functions that are performed frequently, which include voltage, current, and resistance measurement, modern diagrams have many additional options listed below.
Continuity Testing
This function assists in the diagnosis of whether a circuit is closed. A multimeter sounds a beep whenever there is continuity, which indicates that electricity is capable of passing via the circuit.
Diode Testing
The procedure of diode testing is performed using a small voltage and measures the voltage drop across the diode. This tests to see if the diode is working properly.
Capacitance Measurement
Some digital multimeters have a capacitance function which is handy while testing capacitors in circuits during repair.
Temperature Measurement
These types of tasks would require a specialist like an HVAC technician who can use a multimeter that can also measure temperature by using a built-in thermocouple.
Frequency Measurement
This application aids in the measurement of frequency for AC signals which is significant for the operation of electrical devices such as oscillators and signal generators.
How to Use a Multimeter
Using a meter is all about appropriate setting selection, connecting the probes, and obtaining a reading. Simply follow the next steps that are easy to understand and perform the task efficiently:
Measuring Voltage
- Switch the meter onto the measured voltage range (V).
- Join the red probe at the positive terminal and the black one at the negative terminal.
- For measurement of dc, ensure that setting is at dc (usually referred to as V— ), and if ac is to be measured, then ac setting V~ where ~ signically represented there.
Measuring Current
- Turn the switch on the multimeter to a range that is set for measuring current (A).
- Open the circuit and attach the probes in series: red to plus, black to minus.
- If trying to obtain a relatively small current, it could be that the adjusting is appropriate.
Measuring Resistance
- Turn the multimeter settings to ohm (Ω).
- Join the Probes across each end of the side of the component that you want to examine ( They are usually resistors or wires).
- The start figure will be the resistance in ohms showing on the screen reading backward.
Safety Considerations
A multimeter can incorporate high voltage assessment; hence, security measures must be exercised. Here are some crucial safety measures:
Always Start with the Multimeter Off: Before interfacing the device with a circuit, ensure it is off and configured appropriately.
Check for Proper Rating: To avoid risks of harm or equipment damage, connect a meter with the correct peak voltage or current level needed for the task at hand.
Use Correct Probe Positioning: Connect the red probe to the appropriate connector to measure voltage, current, or resistance depending on the task. Connecting probes to the wrong ports may render the multimeter inoperable.
Wear Personal Protective Equipment: Always wear insulated gloves and safety UV goggles when joining high-voltage systems.
Tips for Selecting the Right Multimeter
When selecting a multimeter, the following factors should be considered:
For Beginners: Go for a digital meter with auto range adjustment which is basic. The models’ easy tooling for common purposes.
For Professionals: A high-end digital meter with true RMS, data logging, and additional features to measure capacitance and frequency among other contents is useful.
For Hobbyists: If functionality needs to be weighed against pricing, a slightly expensive digital multimeter can be chosen as it has manual ranging.
Brand Consideration: Popular names such as Fluke, Klein Tools, and Extech manufacture good quality multi-meters that are durable and reliable and come with a warranty and good customer service as well.
Conclusion
Multimeters are important for professional and amateur users alike when dealing with electrical and electronic tasks. Whether diagnosing a home wire fault, testing particular segments of electronic circuits, or pinpointing a fault within an appliance, a meter can accomplish the accuracy and functionality set out to do, ensuring that the work is quick and safe. When choosing the right multimeter for your work, it is important to know the range of meters available, their specifications, and safety precautions.
