Exam Question

### (a) Explanation of the working of a Megger with the aid of its internal circuit
A Megger, or Insulation Resistance Tester, is a specialized instrument designed to measure very high electrical insulation resistance, typically in Megaohms (MΩ). It is crucial for assessing the condition of electrical installations, motors, cables, and other equipment to prevent electrical breakdown, ensure safety, and comply with regulatory standards.
#### Principle of Operation
The fundamental principle behind a Megger's operation is Ohm's Law. It applies a high DC voltage across the insulation being tested and measures the minute current that leaks through the insulation. The resistance is then calculated by the instrument based on the ratio of the applied voltage to the measured current ($$ R = \frac{V}{I} $$). Unlike a standard ohmmeter, a Megger is capable of generating and maintaining the high test voltage (e.g., 500V, 1000V, 2500V, 5000V DC) required to stress the insulation and reveal potential weaknesses.