Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Ohmmeter is
meter to record ohm
Used to measure resistance
Combination of Ohm and Meter
An indicatng instrument
Used to measure resistance
Quick Summary: An ohmmeter is an electrical instrument specifically designed to measure the electrical resistance of a component or a circuit. It functions by applying a small internal voltage to the component and measuring the resulting current flow, then displaying the resistance value based on Ohm's law.
An ohmmeter is an electrical instrument specifically designed to measure the electrical resistance of a component or a circuit. It functions by applying a small internal voltage to the component and measuring the resulting current flow, then displaying the resistance value based on Ohm's law.
R=IVтАЛ тАФ Ohm's Law governing the measurement principle
I=RtotalтАЛVbatteryтАЛтАЛ тАФ Relationship between internal voltage and circuit resistance
The device typically contains an internal DC voltage source (battery) and a sensitive galvanometer or digital converter. When connected in series or parallel across an unknown resistance R, the current I passing through the meter is inversely proportional to R according to I=R+RmтАЛVтАЛ. The meter scale is calibrated to read directly in ohms (Omega) rather than current.
An ohmmeter must never be connected to a live circuit, as the external voltage can damage the internal meter components.
The component to be tested must be isolated from the rest of the circuit to ensure accurate readings.
Modern digital ohmmeters often provide high precision by using constant current sources instead of simple voltage dividers.
Direct reading of electrical resistance.
Essential for testing continuity in wiring and PCB traces.
Requires power source (battery) to operate.
Can be damaged by residual voltage in the component under test.
Checking continuity in electrical cables.
Measuring resistance of coils, heaters, and resistors.
Troubleshooting short circuits and open circuits.
Series-type ohmmeters are commonly used for high resistance measurements, while shunt-type ohmmeters are used for low resistance.
Option A and C are incorrect as they define the term etymologically rather than describing the function of the device.
B is correct тАФ An ohmmeter is specifically engineered to measure electrical resistance in units of ohms.
Always ensure the circuit under test is de-energized before using an ohmmeter to avoid incorrect readings and prevent internal damage to the instrument.