Isolation Transformer
An isolation transformer is a transformer designed to transfer electrical power between two circuits while keeping them electrically separated. It provides galvanic isolation, meaning there is no direct electrical connection between input and output. This improves safety, reduces noise, and protects equipment.
What Is an Isolation Transformer?
An isolation transformer typically has equal number of turns in the primary and secondary windings.
- Primary turns (Np) = Secondary turns (Ns)
- Input voltage ≈ Output voltage
- No direct electrical connection
Working Principle
It works using electromagnetic induction:
- AC voltage applied to primary winding
- Magnetic field is created in the core
- Magnetic flux induces voltage in secondary
- Energy transfers magnetically, not electrically
Voltage Relationship
Since turns ratio is 1:1:
Vp = Vs
The voltage remains the same, but the circuits are isolated.
Why Isolation Is Important
- Protects users from electric shock
- Prevents ground loops
- Reduces electrical noise
- Improves system safety
Galvanic Isolation
Galvanic isolation means there is no direct conductive path between two circuits.
- No shared ground connection
- Energy transfer via magnetic field
- Enhances safety and signal integrity
Applications
| Application | Purpose |
|---|---|
| Medical Equipment | Protect patients from shock |
| Audio Systems | Eliminate noise and hum |
| Test Equipment | Safe troubleshooting |
| Industrial Systems | Protect sensitive electronics |
| Power Supplies | Electrical isolation |
Advantages
- Improves safety
- Reduces noise and interference
- Protects equipment
- Prevents ground loops
Limitations
- Does not change voltage
- Adds cost and size
- Still has transformer losses
Real-Life Example
When repairing a power supply:
- Isolation transformer is used between mains and device
- Prevents direct connection to high-voltage line
- Reduces risk of electric shock
Key Points
- Isolation transformers provide electrical separation.
- Usually have a 1:1 turns ratio.
- Improve safety and reduce noise.
- Used in medical, audio, and testing applications.
- Operate using electromagnetic induction.