Step-Down Transformer Calculator

Calculate step-down transformer specifications including turns ratio, current ratings, core dimensions, wire gauge, and efficiency for power supply and distribution applications.

Step-Down Transformer Principle

    Primary (High V)   Core    Secondary (Low V)
         ┌─────┐      ┌───┐      ┌─────┐
    Vp ──┤ Np  │      │ ⟂ │      │ Ns  ├── Vs
         │ ))) │      │ ⟂ │      │ ((( │
    Ip ──┤     │      │ ⟂ │      │     ├── Is
         └─────┘      └───┘      └─────┘
         
    Vs/Vp = Ns/Np = Turns Ratio (<1 for step-down)
    Ip/Is = Ns/Np (Current steps up)
    Power: Vp×Ip ≈ Vs×Is (minus losses)

Step-Down Characteristics:

Secondary voltage < Primary voltage
Secondary current > Primary current
Turns ratio < 1
Power remains approximately constant

Calculation Type

Basic Calculations Detailed Design

Basic Transformer Parameters

Primary Voltage (High)

Secondary Voltage (Low)

Power Rating

Frequency

About Step-Down Transformers

Step-down transformers reduce voltage from primary to secondary while increasing current proportionally. They are widely used in power supplies, distribution systems, and safety applications.

Key Characteristics:

Voltage Decrease: Secondary voltage < Primary voltage
Current Increase: Secondary current > Primary current
Power Conservation: Input power ≈ Output power (minus losses)
Turns Ratio: Less than 1 for step-down operation

Applications:

Power supply transformers
Distribution transformers
Control circuit transformers
Isolation transformers

Advantages:

Provides safe low voltages for equipment
Galvanic isolation from mains
Efficient power conversion
Reliable and long-lasting