Resistance Substitution Board

Description

A cycle dynamo with crank handle, is fitted on base with two output terminals which are connected in parallel to a lamp holder with a lamp.

Description

A simple kit for students to gain insight into field poles, armatures and switches, one mounting base, two coils of insulated wire , field pole, mounting bracket, two armature halves, one piece of insulating tubing, motor shaft, two commutator insulators, two bronze wire brushes, two shaft supports, four paper fasteners, a AA battery holder and 6 each of screws and nuts. Requires one AA battery, not supplied, with assembly instructions.

Description

Each wound on a rectangular insulated bobbin, connections by 4 mm sockets spaced at 19 mm

Description

Investigate the working principle of circuit breaker type fuse with this demonstration model. The apparatus is built on a robust plastic base and includes resistive loads to simulate external wiring circuits. Applications of the thermal response of bimetal strips and also electromagnetism (movement from a solenoid) are clearly demonstrated in this model. When a 12 V DC supply is connected (not supplied) the LED lights to show that current is flowing in the external circuit and the bi-metal strip can be seen to bend as its heater coil raises the temperature. After a few minutes the bending is sufficient to trip the mechanism and the current path is broken. At any current selection a short circuit situation can be initiated by pressing the red button and this produces an immediate response from the solenoid to disconnect the supply.