An isolation transformer is a transformer in which the input winding is electrically isolated from the output winding. The isolation transformer is used to avoid accidental simultaneous contact with the charged body. The isolation of the transformer is to isolate the current of the original secondary winding around the coil. It was used in the power industry in the early days for European countries, and is widely used as a power source for control power, safety lighting and indicator lights for general circuits in the electronics industry or industrial and mining enterprises, machine tools and machinery.
 
The isolation transformer is a safe power source, which is generally used for machine maintenance and maintenance, and functions as protection, lightning protection and filtering. The principle of an isolating transformer is the same as that of a normal transformer. They all use the principle of electromagnetic induction. Isolation transformers are generally, but not exclusively, 1:1 transformers. Since the secondary is not connected to the earth, there is no potential difference between any of the secondary lines and the earth, but it is safe to use. Often used as a maintenance power source.
 
The power supply that controls the transformer and tube equipment is also an isolation transformer. Power supplies such as tube amplifiers, tube radios and oscilloscopes, and lathe control transformers are isolation transformers. For example, in order to safely repair the color TV, a 1:1 isolation transformer is commonly used. Also used in air conditioning.