What is isolation transformer? Its working, advantages, disadvantages & Applications

An isolation transformer is a type of transformer that is used to transfer isolated AC electrical power to a device or equipment for safety, protection, or to reduce the harmonics and transient voltage surges. It provides isolation between the powered device and power source based on the galvanic isolation where there is no conductive path between the power source and powered device.

The isolation transformers are used for safety purposes, and they are also used to reduce transient and harmonics. It provides galvanic isolation. It means there is no conductive path present between the source and load.

working of isolation transformer:

An isolation transformer is nothing but a simple transformer having a 1:1 transformation ratio. The power source is connected with the primary winding, and the load or circuit needed to protect is connected with the secondary winding.

The isolation transformer is used to reduce the transient from the power source. In power sources, there are many reasons to generate spikes in supply like; lightning, switching, or sudden change in load. This spike increases the voltage level from a few volts to thousand volts. Generally, spikes in voltage waveform are for a very short time (~3 ns). If this spike reaches the load, it may damage the equipment. Hence, it is necessary to reduce.For that, an isolation transformer is used between the device and the power source. Let us assume, there is a high voltage high current spike produces in the supply line. And this spike passes through the primary winding of the isolation transformer. Due to the effect of inductance, the primary winding does not allow a sudden change in current.

Advantages of isolation transformer:

  • It is proven that isolation Transformer can operate at High Frequency, that is why it is also utilised as a vibration and pulse transformer.
  • Isolation Transformer can be utilised for very high and powerful voltage isolation.
  • High performance or efficiency.

Disadvantages of isolation transformer:

  • Meanwhile, whenever the Isolation Transformer acting as Pulse Transformer and it operates at a moderate level of frequency, there is distortion produced independently of the output waveform.
  • When an isolation transformer is operating at DC pulse sign or signal, the saturation property of the core decreases.
  • Isolation Transformer designed specially, which is why it is more expensive than a conventional transformer.


  • A small size isolation transformer is used for isolation in pulse circuits.
  • An isolation transformer with a ratio of 1:1 is used under load conditions (as a power transformer) for safety purposes.
  • Electrical isolation is necessary for medical equipment and some special standard equipment. In that case, an isolation transformer is connected with equipment.
  • An isolation transformer is used to reduce harmonics and transient in electrical circuits.

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