Transformers
2. How Transformers Work (and Why They Love AC)
Transformers are ingenious devices that exploit the properties of AC to efficiently increase or decrease voltage. They consist of two coils of wire — the primary and secondary coils — wrapped around a common iron core. When AC flows through the primary coil, it creates a constantly changing magnetic field in the core. This changing magnetic field, in turn, induces a voltage in the secondary coil. The ratio of the number of turns in the primary and secondary coils determines the voltage transformation.
Think of the transformer as a see-saw for electrical power. If the secondary coil has more turns than the primary coil, the voltage is "stepped up" (increased), but the current is reduced proportionally. Conversely, if the secondary coil has fewer turns, the voltage is "stepped down" (decreased), and the current is increased. The power (voltage times current) remains roughly the same (minus some losses due to inefficiencies), just like the weight on a see-saw remains the same, even if the position changes.
The important point is that this entire process relies on the changing magnetic field created by AC. Without that continuous change, the transformer simply wouldn't work. If you tried to apply DC to the primary coil, you would get a brief pulse of magnetic field when the current is first switched on, but then nothing. No changing magnetic field, no induced voltage in the secondary coil, no voltage transformation. It would be as useful as a chocolate teapot.
So, in essence, the transformer is a tool specifically designed to work with the fluctuating nature of AC. It's a perfect example of how understanding the fundamental properties of electricity allows us to manipulate and control it for our benefit. This is why we can use transformers to efficiently step up or step down AC voltages for power transmission and distribution, something that's far more complex and inefficient with DC.
