Which device is used to measure very high values of resistance?

The megohmmeter is specifically designed to measure very high values of resistance, typically in the megohm range or higher. This device applies a high voltage across the resistance being measured, which enables it to accurately determine resistance levels that are far beyond the capabilities of standard measuring devices.

In contrast, shunt-type ohmmeters are generally used for lower resistance measurements. They cannot handle the high voltage needed for accurately measuring megohms and are intended for applications involving lower resistance ranges.

A standard multimeter typically measures resistance in ohms, and while some advanced models may have the capability to measure higher resistance, they are not specialized for very high resistance values as a megohmmeter is.

A digital voltmeter focuses on measuring voltage, not resistance. Therefore, it cannot perform resistance measurements without involving additional equipment.

Choosing the megohmmeter is appropriate for scenarios where high resistance is involved, such as testing insulation on electrical systems or verifying the integrity of components in aircraft electrical circuits.