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Electrical components - What is a transformer?

A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

Fundamentally, a transformer comprises of two (2) coils of wire wound around a loop/ framework of metallic (iron/steel) material. The two (2) coils of wire are referred to as the ‘primary’ coil and ‘secondary’ coil. The metallic loop is referred to as the ‘core’ of the transformer.

In this arrangement, in accordance with the laws of electromagnetic induction credited to Michael Faraday for discovery in 1831, and James Clerk Maxwell who mathematically described the phenomenon and entitled it “Faraday's law of induction”, given a varying electrical current flowing in the primary coil (IPRI) of the transformer, this will generate a varying magnetic flux (field)(Fm) in the core of the transformer and radiating from the primary coil.

Accordingly, given the magnetic flux/field ‘cuts/impinges on’ the wires of the secondary coil, this will ‘induce’ a secondary electrical current (ISEC) in the secondary coil and duly a varying electromotive force (voltage VSEC) ) will exists across the terminations of the coil. Thus electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits.

Transformers are used to increase or decrease alternating current (AC) voltages in electric power applications. Such transformers being termed as a ‘step-up’ type to increase voltage and a ‘step-down’ type to decrease voltage. Transformers are also used to isolate yet ‘couple’ stages of signal-processing circuits. Since the invention of the first constant-potential transformer in 1885, transformers have become essential for the transmission, distribution, and utilization of alternating current electric power.

A wide range of transformer designs is encountered in electronic and electric power applications. Transformers range in size from radio frequency (RF) transformers less than a cubic centimetre in volume, to units weighing hundreds of tons used to interconnect the electrical power grids.

About the author, …

Eur Ing Dr Robert Brown (Robert) is the Executive Director of Fraser George and Associates Limited and is a Consultant and Forensic Engineer in the fields Electrical Electronic and Control Engineering.

Robert is an accomplished professional Expert Witness having prepared and presented many court compliant reports and presented oral evidence within the High Court, Crown Courts and County Courts.

For further information please contact Robert via;

Email,… or

Tel Land: +44 (0)1777 709175

Tel Mobile: +44 (0) 7976250624

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