Final answer:
Digital ohmmeters with a tone for low resistance are useful for performing continuity tests to check for a closed circuit. They utilize Ohm's law to measure resistance accurately without significantly altering the circuit.
Step-by-step explanation:
Most digital ohmmeters have an audible tone to indicate a closed or low-resistance circuit, making them useful for performing continuity tests. Continuity testing helps to verify that there are no breaks in a circuit and that the electrical connections are secure. The equivalent resistance of a circuit can be measured with an ohmmeter when elements are not marked, which is particularly useful for troubleshooting and ensuring the proper functioning of a circuit.
An ohmmeter's principle is based on Ohm's law (R = V/I), and its accuracy can be greatly enhanced through the use of solid-state electronics and null measurements, allowing for minimal alteration of the circuit during testing. The evolution from traditional to modern digital ohmmeters means they are less likely to affect the circuit they are measuring, due to their higher internal resistance when used as a voltmeter and lower resistance when used as an ammeter.