What Is an Isolation Transformer?
An isolation transformer is a transformer used to electrically separate two circuits from each other, usually without changing the voltage (a 1:1 turns ratio).
What Is Its Purpose?
Not to convert voltage but to provide galvanic isolation. Since there's no direct conduction between input and output, the output side is separated from the mains ground; this reduces the risk of electric shock.
Why Does It Provide Safety?
On a normal mains, a person touching the live wire completes the circuit through ground and gets shocked. Since an isolation transformer's output is independent of ground, touching a single terminal doesn't form a current path. So it's used in service and medical environments.
| Property | Value |
|---|---|
| Turns ratio | Usually 1:1 |
| Voltage | Unchanged |
| Main function | Galvanic separation |
Noise Separation
An isolation transformer also cuts the noise caused by ground loops. Shielded types further reduce high-frequency EMI interference.
Where Is It Used?
Medical devices, electronics service benches, audio systems (ground-loop removal), industrial control and precise measurement environments.
Common Mistakes
- Assuming it steps down voltage: most isolation transformers pass the voltage as-is, they don't step it down.
- Power limit: connecting a load above the VA rating causes heating.
- Bridging the ground: if the output ground is tied to the input, the isolation advantage is lost.
Frequently Asked Questions
Does it regulate?+
How does it differ from a normal transformer?+
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