About transformers

About Transformers

Transformer and Choke

What is a transformer?

The transformer is built from primary and secondary windings and from the heart. The windings are usually enamels of copper or aluminium in the transformer. The traditional transformer is assembled around an iron heart made of transformers.

Transformers are used;

  • To reduce and increase replacement voltages.
  • The galvanic separation of the AC circuits.
  • Electronic circuit impedance.

Transformer operation

The conductor leads around a magnetic field, where the field lines are the wheels of the lead. The total number of field lines is called a magnet (Φ).

Magnetic Flux SI-the unit name is Weber and the symbol Wb (1 Wb = 1 Vs)

Magnetic flux Density (B) denotes the total number of field lines in a unit perpendicular to these (A) against. Magnetic flux density The SI-unit name is Tesla and the symbol T (1 T = Wb/M2). B = Φ/A


When the flow conductor is rotated and equipped with an integrated iron heart, a magnetic circuit is created in which the inner field lines of the coil pass on. The tyre-shaped iron in the heart is then full of magnetic flux. The length of the magnetic circuit is the length of the centre line (l) of the heart ring.
The magnetic flux density (B) in this magnetic circuit is determined by: B = μr x μo x N x I/1


  • μR is the relative permeability of the substance, varying depending on the type of iron, between 500 and 5000 Tm/A
  • μ0 empty (and very accurately also air) permeability worth 4 x 10-7 Tm/A

The input NI is called the ampere rpm , or magnetomotor power (MMV). It is denoted by the symbol FM. The amount of Magnetomotor force per magnetic circuit Length (l) is called the magnetic field strength (H). Magnetic field Strength Unit is ampere/metre and ID A/m

H = NI/L


When the AC is affected by the transformer’s primary windings, it generates a magnetic flux that changes to the iron heart. This alternating flow continues to give rise to electric motor Power (SMV) alternating with the transformer’s secondary windings. This phenomenon is called interinductions.

The SI-unit name of the electric motor power is volt and its symbol is V


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