Demonstration Dynamo- Electrical output via 4mm terminals .Hand powered . May also be a motor powered by 6 to 8V power supply This model is mounted on a base plate 200 x 125mm approx. which also carries a hand-drive pulley 125mm diameter coupled to the smaller dynamo pulley by a rubber belt to give a step-up ratio. Electrical output is via a pair of 4mm sockets and a light emitting diode is provided as simple output indicator. The model may also be used as a motor on 6 – 8V DC supply.