Ohmmeters

An ohmmeter is an indispensable tool used widely across Australian electrical and engineering industries. Its purpose is to measure electrical resistance and the verification of continuity within electrical circuits and components. Available in a range of sizes, voltages, and types, each offering varying levels of accuracy, ohmmeters or ohm meters cater to diverse testing needs in electronics and industrial inspection.

You'll find three main variations of ohmmeters, all of which measure electrical resistance in ohms. These are:

• Micro-ohmmeter for measuring low resistance.
• Standard ohmmeters for general purpose.
• Meg-ohmmeter for measuring high resistance.

Furthermore, various types of meters are available with different sensitivity levels, including micro, mega, and milliohm meters, ensuring the right tool for every resistance measurement task.

How does an Ohmmeter work?

Ohmmeters function by sending a small current through the component being tested. This allows the instrument to then measure the voltage drop across the sample, indicating how much the object resists the current flow, and thus revealing the resistance in ohms.

For accurate resistance measurement, it is absolutely vital that ohmmeters are never used on live circuits. Applying an ohmmeter to a circuit that is already powered can damage the meter and potentially harm the user. To ensure the reliability of your resistance measurement, send your tools for regular calibration such as RS Australia’s in-house calibration service to fine-tune your instruments.

Types of Ohmmeter

Ohmmeters are versatile tools, and specific types are designed for particular resistance measurement ranges. Here's a look at the three main variations:

Micro-Ohmmeter

Micro-ohmmeters are specifically engineered for the precise measurement of very low resistances, typically in the milliohm or micro-ohm range. They are crucial for applications such as testing contact resistance in switchboard components and welded joints.

Standard Ohmmeter

Standard ohmmeters are general-purpose instruments for measuring resistances typically ranging from ohms to kilohms. Commonly found in multimeters, they are used for testing resistors in circuits, checking fuse and breaker continuity, measuring sensor resistance, and troubleshooting electrical wiring.

Meg-Ohmmeter

Meg-Ohmmeters, also known as insulation testers, are designed to measure high resistances, typically in the mega-ohm range and beyond. Their primary application is assessing the insulation resistance of wires, generators, motor windings, and other electrical equipment, helping to identify potential electrical faults or safety hazards.

Important Features of an Ohmmeter

Selecting the right ohmmeter for your tasks involves considering several important features.

• Measurement Range: The range dictates the types of resistance you can measure. For instance, a micro-ohmmeter with a milliohm range is essential for testing low contact resistance in switches, while a meg-ohmmeter with a megaohm range is needed for checking insulation integrity in cables.
• Accuracy/Resolution: Accuracy determines how close the measured value is to the true resistance, crucial for precise component verification in electronics. Resolution indicates the smallest change in resistance the meter can display, important for detecting subtle variations.
• Display Type: Digital ohmmeters with LCD displays offer precise numerical readings, while analogue scales can provide a visual indication of trends and fluctuations in resistance.
• Built-In Test Leads/Probe Types: The type of test leads or probes included affects connectivity. Kelvin clips are ideal for measuring low resistances, while sharp-tipped probes are useful for accessing tight points in circuits.
• Data Logging Or USB Output: Features like data logging allow you to record resistance measurements over time for analysis. Meanwhile, those with ports you can connect a USB cable with enable easy transfer of data to a computer.
• Power Source: Battery-powered ohmmeters offer portability for field work, while rechargeable options provide convenience and can be more cost-effective for frequent use in a workshop.

Industrial Applications of Ohmmeters

Ohmmeters are used in a wide range of applications where the measurement of electrical resistance is required. They are commonly used in the following areas:

Laboratory and Research Environments

Ohmmeters, particularly micro-ohmmeters and high-accuracy standard ohmmeters, are crucial for characterising electronic components, testing new materials, and verifying circuit designs. Researchers use them to precisely measure resistance values in experiments and to analyse the electrical properties of various substances.

Production

Manufacturers use ohmmeters to test the resistance of finished electrical and electronic goods, ensuring components are within specified tolerances and that circuits are correctly assembled. For example, they might be used to verify the resistance of heating elements in appliances or to check the continuity of wiring harnesses in electronic devices before they leave the factory.

Household Troubleshooting

Ohmmeters are also commonly used for troubleshooting electrical issues in residential settings throughout Australia. For instance, standard ohmmeters are used by Australian electrical contractors for circuit continuity testing to identify broken wires or faulty connections in household circuits. They are also helpful for checking the integrity of fuses and the resistance of heating elements in domestic appliances.

What is the Difference Between an Ohmmeter and Multimeter?

While both ohmmeters and multimeters are essential resistance meters for electrical testing, their functionality and capabilities differ significantly.

An ohmmeter is specifically designed for measuring electrical resistance and checking the continuity of circuits. In contrast, a multimeter offers the functionality of an ohmmeter but with the added ability to measure other electrical parameters such as voltage, current, capacitance, frequency, and sometimes even temperature. In terms of pricing, multimeters can be more expensive than ohmmeters due to the difference in features.

How to Choose the Right Ohmmeter

Consider this buying guide for resistance meters, ensuring you find the best ohmmeter for electricians or your specific application from our catalogue.

• Resistance Range Needed: Determine the range of resistance values you'll typically be measuring to ensure the ohmmeter you choose can accurately handle these values.
• Test Voltage Requirement: Consider if your application requires specific test voltages, particularly important for meg-ohmmeters used in insulation testing.
• Portability vs Bench-Top: Decide whether you need a portable, handheld ohmmeter for field work or a more precise bench-top model for laboratory or workshop use.
• Frequency of Use: If you'll be using the resistance meter frequently, consider models with robust build quality and features that enhance efficiency.
• Compliance With Australian Standards: For electrical work in Australia, ensure the ohmmeter complies with relevant Australian safety standards for safe and reliable operation.

Ohmmeter Manufacturer, Supplier & Distributor in Australia

For all your resistance measurement needs in Australia, look to RS Australia, a premier manufacturer, comprehensive supplier, and dependable distributor of ohmmeters. Our extensive catalogue features top-tier brands like Megger, Cropico, and our very own RS PRO range, all available at various price points.

We pride ourselves on offering a wide selection of high-standard instruments, backed by expert technical advisors ready to assist with your specific enquiries and our convenient in-house calibration service.

Buy Resistance Meter Online from RS Australia

Looking for a dependable ohmmeter for your electrical testing needs in Australia?

Finding the perfect resistance meter for your specific application is simple with our user-friendly website. Browse our extensive range of ohmmeters, compare specifications, and add your chosen instrument to your basket. Plus, we provide reliable nationwide doorstep delivery for all ohmmeter orders across Australia. To know more about the delivery times and fees, please visit our Delivery page.

Explore our wide range of resistance meters and buy online today from RS Australia!