Label：Air Gap, Flyback Transformers, Magnetic Reluctance
Nov 3, 202210486
In the comments section of major social media platforms, JRPanel is often asked about the air gap in transformers. So, in this blog, we will specially explain the knowledge of air gap to help you have a basic understanding of it.
We all know that the air gap is generally used in flyback transformers. The flyback transformer works by storing energy in the positive half and then releasing it in the negative half.
Figuratively speaking, we can describe energy as water, and a transformer without an air gap is similar to a water pipe. The water flows in and then flows out directly, and the core cannot store energy.
While a transformer with an air gap in the middle is equivalent to a reservoir, the air gap is equivalent to a dam. When the water comes in, it is intercepted and cannot flow out. After a while, we stopped the water input and started to release the water. Now the water can flow out of the reservoir.
Now you see the Air Gap actually plays a very important role in flyback transformers, and you must be wondering why air gap is able to store energy.
In the transformer, if the core is assembled into the bobbin, the whole structure becomes a closed circuit.
The magnetic reluctance of two sides is very small. The middle is air, compared with this core, the permeability of which is much lower, so its reluctance is relatively large.
The larger the gap, the lower the inductance and the more energy stored.
Here we mention a new concept called magnetic reluctance, which is the resistance of the magnetic path to the magnetic flux.
Magnetic reluctance and resistance in a circuit are somewhat similar.
Imagine there is a circuit, which has a resistor, and a power supply as well as a switch. With the switch closed, most of the electrical energy is trapped in the resistor and is converted into heat.
What if the resistor is replaced with a small bulb? When the circuit is switched on, the small light bulb is lit. This is when the electrical energy is converted into light energy.
Like a circuit, in a magnetic circuit, most of the magnetic energy is trapped where the magnetic reluctance is high. This is the fundamental reason why the air gap is able to store energy.