Simple Circuit Modules.These modules may be used to construct simple circuits of the type normally implemented on for example a Worcester Circuit Board. They are intended to introduce younger pupils (ages 11-13) to some of the more familiar applications of devices and circuits the main emphasis being on simple electrical circuit work.The module is 80 x 40mm and has 4mm plug connections.This module is a heavy-duty reed switch protected by series resistor; a magnet operates the switch.