Explain why resistance coils are usually double wound.

Explanation

**Step-by-Step Solution:**

1. **Understanding Resistance Coils**: Resistance coils are used in various electrical applications to provide resistance in circuits. They are made of materials that have a specific resistance value.

2. **Induction Effect**: When current flows through a coil, it generates a magnetic field around it. This is known as the induction effect. If the coil is wound in a single layer, the magnetic field produced by the current can lead to unwanted inductive effects, such as back electromotive force (back EMF).

3. **Double Winding**: To mitigate the induction effect, resistance coils are typically designed to be double wound. This means that the coil is wound in two layers or loops.

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