A transformer is like a magical relay that changes the voltage of an alternating current (AC) without changing the frequency. Think of it as a power‑leveling device for electricity. 🚀
It uses two coils of wire (primary and secondary) wrapped around a magnetic core. When AC flows through the primary coil, it creates a magnetic field that induces a voltage in the secondary coil. The ratio of the number of turns in each coil determines the voltage change. 🔄
If a transformer were perfect (no energy lost), the power entering the primary equals the power leaving the secondary:
\$Ip Vp = Is Vs\$
Where \$Ip\$ and \$Vp\$ are the current and voltage on the primary side, and \$Is\$ and \$Vs\$ are the corresponding values on the secondary side.
Suppose the primary coil has 100 turns and the secondary coil has 200 turns. The turn ratio is 2:1, so the secondary voltage will be twice the primary voltage (ignoring losses). ⚡️
| Exam Tip |
• Remember: For 100 % efficiency, use the equation \$Ip Vp = Is Vs\$. • If you’re given a turn ratio, you can find the voltage ratio: \$Vs/Vp = Ns/Np\$. • Check units: volts (V) for voltage, amperes (A) for current, watts (W) for power. • Practice converting between primary and secondary values using the ratio. • 💡 Tip: Think of the transformer as a “voltage‑leveling” device—just like a phone charger steps down 230 V to 5 V for your phone. |
Just like a water pump can change the pressure of water without changing the flow rate, a transformer changes voltage without changing frequency. 💧