Demonstraton Electric Bell

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.

Description

Enables students to investigate nature and properties of electricity by using simple circuits which are easily constructed on a base board. The connector system uses P.C.B. strips with cut-out sections whose ends can easily be inserted in spring terminals, ensuring low contact resistance and ease of connection. The kit consists of : 1. Baseboard, plastic, with spring terminals and three battery holders. (1) 2. Batteries. (3) 3. Lamps 1.25 V MES. (10) 4. Lamp holders mounted on PCB connectors. (6) 5. Plain connector PCBs. (10) 6. Wire wound potentiometer with crocodile clip connections. (1) 7. Silicon diode. (1) 8. Resistor 3.9 ohm 2.5 W (1) 9. Pair Leads, red, with crocodile clip at each end. (1) 10. Pair Leads, black, with crocodile clip at each end (1) 11. Pair Leads, yellow, with crocodile clips at each end. (1) 12. Switches mounted on PCB. connectors (2) 13. PVC rod 15 cm long (1) 14. Soft iron nails, 5 cm long (2) 15. Bare copper wire, swg 20 (2 m) 16. Bare eureka wire, swg 34 (2 m) 17. Plastic covered copper wire (2 m) 18. Electrode support (1) 19. Pencil lead electrodes (10) 20. Sheet copper foil, 150 mm square (1) 21. Pack Steel wool (1) 22. Instruction manual in English. (1)

Description

Apparatus is designed primarily for demonstration of the basic principles of transformers. It consists of a laminated U-core with laminated I-core, both with 32 x 25 mm cross section to form a closed core of size 102 x 127 mm. Heavy aluminium alloy stand with removable clamping rods, 2 pole pieces, each 65 x 30 x 25 mm with one end cone shaped, to accept support rod and shading ring. Poles also have a hole drilled through lengthwise to take a light beam.
300 turns
600 turns
1200 turns
3600 turns
12000 turns

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.