What is the purpose of an isolation transformer?

• A. To provide electrical isolation between source and load and to improve safety and impedance separation
• B. To boost voltage
• C. To reduce current
• D. To create single-phase from three-phase

Answer: (B)

The main idea here is galvanic isolation and safety. An isolation transformer uses separate windings with no direct electrical path between the source and the load, linked only through magnetic coupling. That means faults, ground loops, or leakage on one side don’t create a direct shock or fault on the other side, which greatly improves safety. The magnetic coupling also helps with impedance separation and common‑mode noise rejection, so transients or disturbances on the supply are less likely to affect the equipment on the load side.

Boosting voltage isn’t the purpose of an isolation transformer. If voltage change is needed, a different type of transformer (a step-up or step-down) would be used, but the defining feature of an isolation transformer is keeping the two circuits electrically apart while transferring power. It also isn’t meant to create single-phase from three-phase. The key takeaway is the electrical isolation and associated safety and noise-improvement benefits.