Laminated low-loss core for attaching different coils to demonstrate the step up and step down transformer principle. Attractive demountable transformer with clearly labelled coils for GCSE physics and science and A-Level physics demonstrations. The principles used show how transformers are used in domestic electrical appliances and in the National Grid for power transmission. The core (code: PH0849/1) is made up of highly permeable U-shaped metal sheeting, which can be closed via two clamps with tightening screws.