Question

How works a transformer?

Answer 1

A transformer is a device that changes the voltage of electrical energy. It works on the principle of **electromagnetic induction**. Here's how it works in simple terms:

### 1. **Basic Structure**:
   - A transformer has two coils: the **primary coil** (input) and the **secondary coil** (output).
   - Both coils are wound around a **core**, usually made of iron or steel, which helps guide the magnetic field.

### 2. **How it works**:
   - When **alternating current (AC)** flows through the primary coil, it creates a **changing magnetic field** around it.
   - This changing magnetic field passes through the core and induces a current in the secondary coil. This is called **electromagnetic induction**.

### 3. **Voltage Change**:
   - The number of turns (loops) in the primary and secondary coils determines the change in voltage. This is known as the **turns ratio**.
   
   - If the secondary coil has more turns than the primary coil, the transformer **increases the voltage** (step-up transformer).
   - If the secondary coil has fewer turns, the transformer **reduces the voltage** (step-down transformer).

   The voltage and current are related through the equation:
   \[
   \frac{V_1}{V_2} = \frac{N_1}{N_2}
   \]
   Where:
   - \(V_1\) and \(V_2\) are the voltages in the primary and secondary coils, respectively.
   - \(N_1\) and \(N_2\) are the number of turns in the primary and secondary coils, respectively.

### 4. **Energy Conservation**:
   - Transformers do not create or destroy energy. The power that enters the transformer (voltage × current) stays approximately the same on both sides, though the voltage and current might change.
   
   - So, if the voltage is increased, the current is decreased (and vice versa) to keep the power constant.

### 5. **Why use transformers?**
   - **Step-up transformers** are used to increase voltage for long-distance power transmission, which reduces energy loss.
   - **Step-down transformers** are used to lower the voltage to safer levels for use in homes and businesses.

In short, a transformer takes in AC electricity, creates a changing magnetic field, and then uses that field to change the voltage for practical use.