Megohmmeters are normally used to test which property?

• A. Insulation
• B. Conductivity
• C. Capacitance
• D. Inductance

Answer: (A)

Megohmmeters test insulation resistance. They apply a high DC voltage to the insulation and measure the leakage current to determine how much resistance the insulation offers, typically read in megohms. A high insulation resistance means the material is effectively preventing leakage current, indicating good insulation. If the resistance is low, leakage paths, moisture, or damage are present and insulation is compromised. This is different from measuring conductivity (how readily current flows through a material), capacitance (which involves storing charge and is measured with AC impedance tests), or inductance (related to magnetic energy storage, measured with different instruments).