What type of resistance does a megger measure?

A megger, or insulation resistance tester, is specifically designed to measure very high resistance values, typically in the range of megohms. The primary function of a megger is to assess the insulation quality of electrical components and systems, ensuring that they are safe and free from faults that could lead to short circuits or leakage currents. High resistance measurements are crucial for evaluating the integrity of insulation, which protects against electrical failures.

Other types of resistance measurements, such as low resistance and dynamic resistance, do not pertain to the primary applications of a megger. Low resistance measurements are generally taken with a different type of instrument designed for lower resistance ranges, such as ohmmeters or resistance bridges. Dynamic resistance, on the other hand, is more applicable to semiconductor devices where the resistance can change with current or voltage levels and is not relevant to the static insulation tests that a megger performs. Thus, the focus on very high resistance is what makes the megger an essential tool for electricians and engineers in ensuring safe and reliable electrical systems.