Bare Eureka (Constantan) Wire – 0.45 mm Diameter (26 SWG), 125 g Reel

This Bare Eureka (Constantan) Wire is supplied on a 125 g reel and manufactured to a 0.45 mm diameter, equivalent to 26 SWG (Standard Wire Gauge). Made from a copper–nickel alloy with a very low temperature coefficient of resistance, this wire is ideal for experiments where stable and predictable resistance is essential. It is commonly used for constructing precision resistance coils, bridge circuits, and Ohm’s law investigations in school and college physics laboratories.

Flexible, easy to work with, and highly reliable, Constantan wire maintains consistent performance across temperature changes, making it perfect for accurate and repeatable electrical experiments.

Key Features

• 125 g reel of bare Eureka/Constantan wire
• 0.45 mm diameter (26 SWG)
• Copper–nickel alloy with low temperature coefficient
• Excellent for constructing resistance coils
• Provides stable, predictable resistance values
• Easy to wind, shape, and connect in circuits
• Ideal for physics and electronics demonstrations

Ideal for School Science Lessons

Perfect for KS3–KS5 physics, this wire supports investigations such as:

• Building precision resistors and resistance coils
• Demonstrating Ohm’s law with consistent results
• Comparing resistance across different materials and wire gauges
• Investigating temperature effects on electrical resistance
• Setting up bridge circuits, rheostats, and sensor experiments

Reliable and versatile, this Constantan wire is an essential material for electrical and resistance‑based practical work in any school physics laboratory.