School Science/How to make a transformer
This article explains how to make a demonstration transformer. A transformer is a device that converts one AC voltage to another. A detailed description of how they work is given under transformer. The purpose of this page is to give details of how a demonstration transformer can be made very simply in a classroom in order to teach the basic principles. Demonstrations similar to this are usually performed in schools by pupils aged around 13 years old, under the supervision of a qualified science teacher.
You will need 
- Some pieces of soft iron, preferably in a U shape but a cylinder will do.
- Plastic-coated wire
- Some 6 V mes bulbs (torch/flashlight bulbs) in a suitable bulb holder
- Connecting wire with 4 mm plugs
- Alligator clips
- A 4 V AC power supply that is fitted with a 5 A trip switch (IMPORTANT!) Under no circumstances should this homemade transformer be plugged into home current.