A simple iron-cored transformer operates on the principle of electromagnetic induction. It uses two or more coils of wire, called coils, that are electrically isolated but magnetically linked. The core is typically made of iron, which enhances the magnetic flux.

The transformer consists of a primary coil and a secondary coil. An alternating current (AC) is supplied to the primary coil. This alternating current creates a time-varying magnetic field in the iron core.

This changing magnetic field then induces an electromotive force (EMF) in the secondary coil. According to Faraday's Law of Electromagnetic Induction, the magnitude of the induced EMF is proportional to the rate of change of the magnetic flux and the number of turns in the coil. The ratio of the number of turns in the primary coil (Np) to the number of turns in the secondary coil (Ns) determines the voltage transformation ratio.

Voltage Transformation Ratio:

• Step-up Transformer: If Ns > Np, the secondary coil has more turns than the primary coil. The voltage in the secondary coil is higher than the voltage in the primary coil. This is used to increase voltage for long-distance transmission.
• Step-down Transformer: If Ns < Np, the secondary coil has fewer turns than the primary coil. The voltage in the secondary coil is lower than the voltage in the primary coil. This is used to reduce voltage for safe use in homes and appliances.

The iron core plays a crucial role in the transformer's operation. It concentrates and guides the magnetic flux produced by the primary coil, ensuring that the magnetic field links efficiently with the secondary coil. Without the iron core, the magnetic flux would be weaker and less effective in inducing a voltage in the secondary coil. The iron core also reduces core losses, which are losses due to hysteresis and eddy currents in the core material.

The voltage ratio of a transformer is directly proportional to the ratio of the number of turns in the primary and secondary coils. The formula for the voltage ratio (Vp/Vs) is:

Vp/Vs = Np/Ns

Where:

• Vp = Voltage in the primary coil
• Vs = Voltage in the secondary coil
• Np = Number of turns in the primary coil (100)
• Ns = Number of turns in the secondary coil (500)

Therefore, Vp/Vs = 100/500 = 1/5 = 0.2

This means that the secondary voltage is 1/5th of the primary voltage. Specifically, the output voltage (Vs) is 0.2 times the input voltage (Vp). Since the secondary coil has more turns than the primary coil, the transformer is a step-up transformer. This indicates that the input voltage is lower than the output voltage. The transformer increases the voltage from the primary to the secondary side.

Calculation of power loss:

P = I²R = (6A)² * 0.5Ω = 36 A² * 0.5Ω = 18 W

Explanation of power loss with increased voltage:

If the voltage is increased to 24V, the current will also increase. Using Ohm's Law (V = IR), if R is constant, then I = V/R. So, with V = 24V and R = 0.5Ω, the new current (I) would be 24V / 0.5Ω = 48A.

The new power loss would be P = I²R = (48A)² * 0.5Ω = 2304 A² * 0.5Ω = 1152 W.

Comparing the two power losses (18W and 1152W), it is clear that the power loss would be significantly greater if the voltage were increased to 24V. This is because the power loss is proportional to the square of the current, and the current increases with the square of the voltage.