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 modules have 4mm plug connections.A cluster of three ORP12s in parallel; the resistance is approximately 200 Ohm in room lighting to give greater sensitivity and control the current in a reed relay.