Ohmmeter

Definition

An ohmmeter is an electrical instrument used to measure the resistance of a component or circuit. It operates by passing a known current through the resistor and measuring the voltage drop.

5 Must Know Facts For Your Next Test

1. Ohmmeters can be either analog or digital, with digital being more common in modern applications.
2. The unit of resistance measured by an ohmmeter is the ohm, symbolized by Ω.
3. Before using an ohmmeter, it is crucial to ensure that the circuit or component is not connected to any power source to avoid damage and inaccurate readings.
4. Some advanced ohmmeters have multiple ranges that allow for more precise measurements across different levels of resistance.
5. Using an ohmmeter incorrectly, such as applying it to a live circuit, can result in damage to both the instrument and the circuit.

Review Questions

• What safety precautions should you take before using an ohmmeter?
• How does an ohmmeter measure resistance in a circuit?
• What are some differences between analog and digital ohmmeters?

Related terms

Ammeter: An electrical instrument used to measure the current flowing through a circuit.

Voltmeter: A device used for measuring electrical potential difference between two points in a circuit.

Multimeter: An electrical measuring instrument that combines several measurement functions in one unit, typically including voltage, current, and resistance.