The "translator" of Electrical Energy: Transformer

I. Why is It so Important?

Electricity needs to take a long "journey" from power plants (such as hydropower stations and wind farms) to your home. In this process, the transformer plays an indispensable role:

"Boost voltage" for operation to reduce losses: The electricity voltage generated by power plants is not high enough (for example, 10,000 volts). If it is directly transmitted over long distances, the current will be very large, the wires will heat up, and a large amount of electricity will be wasted on the road. At this point, the step-up transformer acts like a "strongman", raising the voltage to hundreds of thousands or even millions of volts. According to Joule's law, the higher the voltage, the smaller the current when transmitting the same power, and the loss on the line is greatly reduced.

Metaphor: It's like using a high-pressure water gun to deliver water over a long distance. The pressure is high, the water flow is fine, it can shoot far and save water.

"Voltage reduction" into households, safe use: High-voltage electricity is extremely dangerous and must never be directly brought into homes, factories or offices. So, the square green iron box that sometimes makes a "buzzing" sound that you see near the residential area and on the utility poles is the step-down transformer. It gradually reduces the high voltage of tens of thousands of volts to the safe voltage of 220V (for household use) or 380V (for industrial use).

Metaphor: Just like before entering a house, turning the water flow from a high-pressure water gun into a gentle water from a faucet.

Ii. How does it work? (Core principle

The working principle of a transformer is based on a great discovery in physics - electromagnetic induction.

It usually consists of two parts:

Primary coil: The coil connected to the input power supply.

Secondary coil: The coil connected to the output power supply.

Core: Connects two coils, providing an efficient path for the magnetic field.

The process (the magical three-step procedure) :

Electricity generates magnetism: When alternating current passes through the primary coil, a constantly changing magnetic field is produced around it.

Magnetic induction iron: This changing magnetic field is conducted along the iron core to the secondary coil.

Magneto-electricity generation: A changing magnetic field cuts through the wires of the secondary coil, thereby inducing a new voltage in the secondary coil.

Key formula:

Primary voltage/secondary voltage ≈ the number of turns in the primary coil/the number of turns in the secondary coil

Want to raise your blood pressure? (Output voltage > input voltage

Let the number of turns in the secondary coil be more than that in the primary coil! This is called a step-up transformer.

Want to lower your blood pressure? (Output voltage < input voltage

Let the number of turns in the secondary coil be fewer than that in the primary coil! This is called a step-down transformer.

Remember: A transformer can only change the voltage of alternating current, but not that of direct current.

Iii. What do transformers look like in daily life?

You can see their different forms almost every day:

Power transformers: The most common ones are the "big oil drums" on utility poles or box-type substations in residential areas. It is filled with insulating oil for heat dissipation and insulation.

Electronic transformer: It's right beside you!

Mobile phone charger: Its core is a micro transformer that converts 220V household voltage into 5V safe voltage.

Laptop power adapter (that "big brick") : It's also a transformer.

There are various small transformers in electronic devices such as audio equipment and radios.