Demonstration Dynamo 
This model is mounted on a base plate 200 x 125 mm approx. which also carries a hand-drive pulley 125 mm 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.