Air Core Transformer

What is Air Core Transformer?

Air Core transformer study: An air-core transformer works on high-frequency electricity. This transformer has cylindrical or toroidal shapes for working purposes. Nowadays, many electric devices are using this kind of form of transformer.

This transformer has many benefits with some limitations. All of the details about the transformer are given on this blog site. Please read carefully and learn a lot about it that you didn’t know before.

All About Air-Core Transformer?

Air-Core Transformer is a special type of transformer whose core is hollow. The windings of an air-core transformer are wrapped around a nonmagnetic core. It can move through the air. It is also seen in radio-frequency circuits.

Compared to iron-core transformers, the level of connection between the windings in this type of transformer is many times less, which means less electromagnetic force. However, eddy current loss, hysteresis, saturation, etc., can operate at much lower and higher frequencies in such windings.

Air-Core Transformer
Air-Core Transformer

Construction of Air-Core Transformer

An Air-core transformer is made by winding windings on tapped solenoids. Air core transformers are parallel to a capacitor. As a result, it can tune with resonance. The primary winding is connected to the ground by a radio antenna.

The secondary winding is parallel to a variable capacitor so that it can resonate with the resonator. Output is taken from the tap point for magnification. Radio receivers use small millimeter size, and large radio receivers use large air-core transformers.

The unprotected air-core solenoid transformers are connected at right angles to each other to prevent bad connections.

Construction of Air-Core Transformer
Air-Core Transformer Construction


Circuit Diagram of Air Core Transformer

The solenoid wire with the hollow tube is made of a twisted air-core transformer. The transformer has no external core. Primary winding and secondary winding are kept side by side.

When AC flow is completed in the primary winding, a magnetic field is created around it, which affects the secondary winding, and thus the secondary winding is supplied with electricity.

Circuit Diagram of Air Core Transformer
Air Core Transformer Circuit Diagram

Primary windings connected with the AC source and the secondary windings connected with the load. Two of the windings are not connected with any physical wire—they exchange electricity through the air. The primary current is V1. The secondary current is V2. The primary winding is N1. The secondary winding is N2. Here the question is, N1/N2=V1/V2.

Working Principle of Air-Core Transformer

The working principle of an air-core transformer is straightforward. This type of transformer has no core for magnetic flux. The insulating copper wire is wound on a non-magnetizing surface like cardboard or plastic tube. A nonmagnetic component can’t transmit EMF flux to the secondary windings.

An air-core transformer uses air for the EMF flux. For this reason, this transformer creates zero noise, zero dissipation, and zero distortion during operation. Eddy currents and hysteresis loss were not found in this transformer.

What is the Benefit of Air-Core core?

The air-core transformer is not heavy as the iron core. Many electrical circuits use this kind of transformer. The main benefit of the transformer is it works on high voltage of electricity transmitted from the primary to the secondary core. It doesn’t create extra noise. Continuously perform 24 hours at a long, zero dissipation, and zero distortion.


The ability of the air core to carry magnetic flux is 1500 times less than an iron core. This means that the power of magnetic flux of an air core is 1500 times lower than an iron core transformer. It can not perform well in large loads with low frequency.

Uses of Air-Core Transformer

Air core transformers are used for radiofrequency. Modern electronic devices are widely used in this kind of transformer. The efficiency of the transformer is 99%, with no hysteresis losses. Some electronic devices which are using this transformer are given below:

  • Electric circuit
  • Computer
  • Television
  • Radio
  • Water heater
  • Oven

NOTE: It is used in many more devices.


The transformer is a big a heavy device. It uses for electric procedures. But some electronic device needs a small transformer with high work efficiency. For this reason, the air-core transformer was invented. It is a small transformer.

It has no core for containing the magnetic flux. It works on the air. The transformer has many shapes for its uses. Although having some limitations, it makes modern electronic devices cheap, available and usable.


About the Author: Mehedi Hasan

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