Shielding protects an analog meter from:

Shielding protects an analog meter from:

• A. Damage due to careless handling.
• B. Harmful UV rays.
• C. Over-current and surges.
• D. Stray magnetic fields.

Answer: (D)

Shielding is used to reduce the influence of external magnetic fields on the meter’s sensitive magnetic movement. An analog meter, especially a moving-coil instrument, can be affected by stray magnetic fields from nearby motors, transformers, or wiring. These stray fields can exert a small torque on the coil and cause the needle to deflect or drift, giving inaccurate readings. A shield made from a high-permeability material provides an easier path for magnetic flux, diverting the external field away from the meter’s movement and stabilizing the indication. This is why shielding protects from stray magnetic fields. It’s not primarily about protecting the meter from UV exposure, mechanical damage, or electrical surges, which require different protections.

Shielding is used to reduce the influence of external magnetic fields on the meter’s sensitive magnetic movement. An analog meter, especially a moving-coil instrument, can be affected by stray magnetic fields from nearby motors, transformers, or wiring. These stray fields can exert a small torque on the coil and cause the needle to deflect or drift, giving inaccurate readings. A shield made from a high-permeability material provides an easier path for magnetic flux, diverting the external field away from the meter’s movement and stabilizing the indication. This is why shielding protects from stray magnetic fields. It’s not primarily about protecting the meter from UV exposure, mechanical damage, or electrical surges, which require different protections.