How a Multimeter Works In Measuring Resistance

Electrical appliances technically should make work easier, but occasionally this is not possible and figuring out exactly how some work may send your mind spinning and overwhelm you. In this piece, we will cover all things multimeter in an attempt to unravel this appliance and specifically figure out how this multimeter is used to determine resistance and in this way, figure out its use.

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Multimeters and Resistance

A multimeter is an electronic instrument that aggregates several measurement functions in one, hence the name ‘multi’ meter. In other words, it serves as a one-stop-shop for all your electronic needs. It may be used to measure resistance, current or voltage, and it is for this reason, also called a volt-ohm-milliameter or VOM.   It is handheld and usually has a digital display for reading the voltage-current or resistance. It serves to detect faults and complex diagnostics. They are used to troubleshoot the problems in appliances, motors, and circuits.

Electrical resistance is the opposition a device offers to the flow of current. Several factors come into play to influence the resistance of a circuit or device, and these include material, thickness, and length. These factors are essential in determining whether a material is a good conductor or a poor conductor or in other words, an electrical insulator or an electrical conductor. Resistance is usually measured in ohms denoted Ω.

Resistance may be derived from voltage and current is given that both are known using the Ohm’s law, or it may be measured using a simple instrument like an ohmmeter or a compound instrument like the multimeter. A resistor is an electrical component that is used to impede the flow of current. There are various kinds of resistors; some are fixed while others are variable.

Types of Multimeters

There are analog and digital multimeters. Analog multimeters are useful in detecting slow changes in voltage as you can see the needle moving over the scale gradually. They may, however, prove challenging to obtain accurate results from, and thus most users prefer the use of digital multimeters. Most multimeters in use currently are therefore digital and deliver higher accuracy and reliability.

Parts of multimeters

The regular multimeter has the following parts: a display, buttons, rotary switch, and input jacks. The display shows the readings and also acts as a display for the input measurements. The buttons vary depending on the model in use and serve various functions. The rotary switch or dial, as it is more commonly called, is used to select the measurement values. The input jacks provide a port for inserting the leads. The leads are conductors between the device being tested and the multimeter

How to Measure Resistance with Multimeter

1. If the component being measured is connected in any way to a power source, turn off the power source.
2. The object being measured must be disconnected from any existing circuits as the multimeter works by applying a voltage across the object being measured
3. Insert the red lead to the positive input jack, and the black lead to the negative input jack.
4. Turn the dial initially to the lowest ohmic value in the ohm region then adjust the dial to a resistance greater than that being measured for optimum sensitivity.
5. The ranges are from 200ohms to 2megaohms

Thus to measure 1-ohm resistance adjust the dial to the 20-ohm reading

Purpose

Multimeters serve a variety of functions and these include

• Testing transistors and capacitors
• Checking for continuity of wires
• Troubleshoot electrical and electronic equipment

Best Budget Multimeters

So with all this newfound information on all things, multimeter one might then be faced with the dilemma of which multimeter best suits your needs. The list is quite long, but a few make it into the top five. These are the best budget multimeters available.

These include:

• Fluke 179 true-RMS Digital Multimeter
• Fluke 87V industrial multimeter
• CL380 Digital clamp meter
• Fluke 115 compact multimeter
• Ex 470 multimeter and infrared thermometer

How Do You Check Ground Resistance with a Multimeter

A multimeter may also be used to determine ground resistance. Electricity tends to find the path of least resistance to the ground. So it is vital to measure grounding system resistance regularly to determine safety. The ground system should have a resistance of no more than 25Ω. Faulty grounding is dangerous and may leave your house vulnerable to fires, and thus it is essential to note the grounding frequently.

Determining ground resistance:

• Connect the multimeter probes to the meter red to the positive jack, and the black lead to the negative jack.
• Turn off any current previously flowing in the circuit
• Set the multimeter to ohms
• Connect the red lead to the neutral
• Touch the black lead to the earth port in the socket

How to Choose a Multimeter

In an attempt to simplify the search for a multimeter here are a few things to consider in making the purchase

Check the available probe leads available and determine which will suit your needs best. Your options range between test probes, alligator clips, and IC hooks. Depending on what appliance the resistance is being measured, the choice should fit like a glove.

Check the resistance range for the meter to be sure it works for the item being measured. Be sure it gives you enough of an allowance to measure resistance effectively

Determine what other additional features would be useful in your multimeter and be sure to pick a meter that meets these needs. Though this may not be a deal-breaker if you could land a multimeter that functions in measuring continuance and capacitance, then why not.

As in all necessary purchases, price plays a vital role in deciding which multimeter to pick. The multimeter of your choice should not dent your pockets as there are a wide variety of multimeters available for purchase at all price ranges.

Safety

For safety precautions, refer to the user manual. Also, for purposes of safety, keep your fingers away from any conducting part of the appliance and handle only the plastic or insulated regions. When the multimeter is being used for testing large power sources, safety goggles should be used as a safety precaution method. Frequently inspect your wiring for any damages to prevent accidental short circuits or other accidents.