1 Answer
The working principle of a transformer is based on **electromagnetic induction**. It works by transferring electrical energy between two or more coils (windings) through a magnetic field, without a direct electrical connection between them.
Here's a step-by-step explanation:
1. **Alternating Current (AC) Input**: When an alternating current (AC) flows through the primary winding (input coil), it creates a changing magnetic field around the coil.
2. **Magnetic Field Generation**: The changing magnetic field produced by the primary winding induces a magnetic flux (lines of magnetic force) in the transformer's core, which is typically made of iron or another magnetic material.
3. **Magnetic Flux Linkage**: This magnetic flux then links with the secondary winding (output coil). The core helps in guiding the magnetic flux from the primary winding to the secondary winding efficiently.
4. **Induced Voltage in the Secondary Coil**: According to **Faraday's Law of Induction**, a changing magnetic field induces a voltage in any coil of wire that the magnetic flux passes through. So, the changing magnetic field in the core induces a voltage in the secondary winding.
5. **Output Voltage**: The voltage induced in the secondary coil depends on the number of turns in the primary and secondary coils. This relationship is given by the **transformer equation**:
\[
\frac{V_s}{V_p} = \frac{N_s}{N_p}
\]
Where:
- \( V_s \) is the secondary voltage
- \( V_p \) is the primary voltage
- \( N_s \) is the number of turns in the secondary coil
- \( N_p \) is the number of turns in the primary coil
6. **Energy Transfer**: The energy is transferred from the primary coil to the secondary coil through the magnetic field, and depending on the turn ratio of the coils, the voltage can either be stepped up (increased) or stepped down (decreased).
### Key Points:
- A transformer only works with alternating current (AC), because the changing magnetic field is required for inducing voltage.
- The transformer does not change the frequency of the AC; it only changes the voltage.
- The power (ideally) remains constant in the transformer, so \( V_p \times I_p = V_s \times I_s \), where \( I_p \) and \( I_s \) are the currents in the primary and secondary coils, respectively.
This is how transformers efficiently transfer electrical energy across different voltages while maintaining the overall power.
Here's a step-by-step explanation:
1. **Alternating Current (AC) Input**: When an alternating current (AC) flows through the primary winding (input coil), it creates a changing magnetic field around the coil.
2. **Magnetic Field Generation**: The changing magnetic field produced by the primary winding induces a magnetic flux (lines of magnetic force) in the transformer's core, which is typically made of iron or another magnetic material.
3. **Magnetic Flux Linkage**: This magnetic flux then links with the secondary winding (output coil). The core helps in guiding the magnetic flux from the primary winding to the secondary winding efficiently.
4. **Induced Voltage in the Secondary Coil**: According to **Faraday's Law of Induction**, a changing magnetic field induces a voltage in any coil of wire that the magnetic flux passes through. So, the changing magnetic field in the core induces a voltage in the secondary winding.
5. **Output Voltage**: The voltage induced in the secondary coil depends on the number of turns in the primary and secondary coils. This relationship is given by the **transformer equation**:
\[
\frac{V_s}{V_p} = \frac{N_s}{N_p}
\]
Where:
- \( V_s \) is the secondary voltage
- \( V_p \) is the primary voltage
- \( N_s \) is the number of turns in the secondary coil
- \( N_p \) is the number of turns in the primary coil
6. **Energy Transfer**: The energy is transferred from the primary coil to the secondary coil through the magnetic field, and depending on the turn ratio of the coils, the voltage can either be stepped up (increased) or stepped down (decreased).
### Key Points:
- A transformer only works with alternating current (AC), because the changing magnetic field is required for inducing voltage.
- The transformer does not change the frequency of the AC; it only changes the voltage.
- The power (ideally) remains constant in the transformer, so \( V_p \times I_p = V_s \times I_s \), where \( I_p \) and \( I_s \) are the currents in the primary and secondary coils, respectively.
This is how transformers efficiently transfer electrical energy across different voltages while maintaining the overall power.