Which device is typically used for very high resistance measurements?

The device typically used for very high resistance measurements is the megohmmeter. This instrument is specifically designed to measure resistance in the high megohm range, which is ideal for testing the insulation of electrical systems and ensuring safety by checking for insulation breakdown.

The megohmmeter applies a high voltage to the component being tested, which allows for an accurate measurement of resistance over very large values, often in the millions of ohms. This is crucial for applications where low leakage currents need to be identified, such as in motors, cables, and electrical circuits.

While voltmeters and ohmmeters can measure resistance, they are limited in their capacity to measure high resistance values effectively. An ammeter, on the other hand, measures current and is not suitable for resistance measurements at all. Thus, the megohmmeter stands out as the appropriate device for high resistance scenarios.