Air Core Transformer

Air Core Transformer

An Air core transformer designed to be used at a high frequency, used in radio circuits. The currents are usually small but the voltages can very. They can be used to change voltages, match one stage to an other, for matching antennas to the radio circuit. They have many uses with in a radio.

As the name describes they consist of wire wound around something non- magnetic. Paper, plastic or ceramic may be the form that they are rapped around. Other transformers are simple loops of wire forming a long spiral with an additional loop of wire rapped in parallel to the original coil. Sometimes one coil is inside the other coil.

Air core transformers are intended for transporting Radio-frequency currents. One example is the electric current energy used to accomplish radio transmission.

The function of an air core transformers is a based on the induction between two magnetically linked coils or windings. The transformer consists of a primary and a secondary coil.

It works on 2 principles…

• Electrical currents produce magnetic fields which are called electromagnetism.
• An altering magnetic field inside a coil of wire induces or stimulates a voltage from one end to the other end of the coil. This is referred to as electromagnetism induction.

In most circumstances, the wire coils are wound onto a rectangular cardboard-like structure so that the core substance air is resulting in the transformer being referred to as an air core transformer.

There are certain points that makes air core transformers different from other types.

• They do not contain iron or ferromagnetic cores.
• Unlike electrical and power transformers, which utilize their cores to create a flux, air core transformers create flux using the windings and the air passing through them.

Here are some reasons why air core transformers are chosen for small sized, portable electronic devices…

1. There is no distortion.
2. No dissipation of signal quality.
3. We get noise free operation.
4. There are no losses in terms of hysteresis and eddy currents.
5. As they do not contain ferromagnetic cores, they do not weigh much.

1. Air core used is when losses are to be kept minimum, and a good frequency response and performance is desirable over range of frequencies. Iron core or ferrite core transformer has limitations of frequency and may suffer from some undesirable distortions, apart from hysteresis and eddy current losses.
2. Air core transformer is a made by winding coils one over the other on hollow plastic , bakelite or paper core. The hollow serves ascair core.

Every transformer with different number of turns can be used as either step up or step down transformer. It only depends on the purpose and connections.