An ohmmeter or ohm meter is an electronic device that precisely measures resistance in an electrical circuit and components to determine their optimised resistance. These instruments verify if there are any faults or defects in various circuits, including open circuits or short circuits. An ohmmeter is a must-have tool for electrical, engineering, electronics, and automotive repair, as well as for household electrical troubleshooting. Many multimeters also integrate modern ohmmeters, making them versatile tools for diagnosing and troubleshooting electrical circuits and components.
What are the Benefits of Using Ohmmeters?
Using precision ohmmeters provides unparalleled benefits in various aspects. These test and measurement devices are indispensable tools for electricians, technicians, and engineers, giving quick measurements when diagnosing electrical problems. They are a safe, accurate, and efficient way of locating areas of high resistance in electrical circuits and help prevent electrical overloads and overheating. Additionally, identifying and rectifying these high-resistance points using ohmmeters reduces the risk of electrical fires and accidents, enhancing overall efficiency and system performance.
Popular Types of Ohmmeters
Ohmmeters are available in various types based on their operation, design, and measurement ranges, such as:
- Analog Ohmmeters – These instruments provide resistance measurements using a moving needle-style display that moves over a scale. These meters are relatively simple; however, they are less commonly used today for basic resistance measurements.
- Digital Ohmmeters – These provide a digital readout (in numerical form) of resistance and are more accurate and easier to read than analog meters. A digital ohmmeter comes in various forms––from handheld designs to benchtop models, and is the most modern ohmmeter with additional features, including data logging and auto-ranging.
- Handheld Ohmmeter – Also called portable ohmmeters, a handheld ohmmeter can be easily carried around and used in the field. They are often battery-powered and have digital displays.
- Milli Ohmmeters – They are specialised low-resistance ohmmeters that measure electrical resistance in milliohms (mΩ). They accurately measure very low resistance values, typically encountered in electrical and electronic circuits, such as the resistance of wires, connectors, or components.
- Micro-Ohmmeters – Micro-ohmmeters measure extremely low resistances, often in the micro-ohm or milli-ohm range. They are commonly used for testing electrical connections, such as welds and busbars.
- Megohmmeter (Megger) – A megohmmeter, or simply "megger," is an ohmmeter used to measure extremely high resistances, often in the megohm range. It is commonly used for testing the insulation resistance of electrical cables and equipment.
- Benchtop Ohmmeter – Benchtop ohmmeters are larger, more precise instruments typically used in laboratory or workshop settings. They offer higher accuracy and additional features for more complex measurements.
Typical Applications of Ohmmeters
Ohmmeters are commonly used in various applications in electronics, electrical engineering, and other fields where the measurement of resistance is essential. Some typical applications of ohmmeters include:
- Continuity Testing
- Electrical Maintenance
- Fault Detection
- Component Testing
- Quality Control
- Circuit Troubleshooting
- Grounding and Bonding Checks
- Wire Identification
- Temperature Sensor Calibration.
