Resistance Substitution Box

Description

A very effective and motivating learning aid in elementary electromagnetism. Consists of 8 anisotropic alloy magnets, 8 ceramic ferrite magnets, 4 steel magnet yokes, 6 plotting compasses, 4 hardboard formers to take compasses, 1 bottle iron filings 250 gm, 4 dispensers for iron filings , 4 double C-cores, 4 clips for C cores, 4 Aluminium rings, 4 Aluminium split rings, 4 armatures with axle tubes, 4 Aluminium axle rods, 8 split pins, 16 rivets, 4 formers for coils, 4 reels cello tape, 4 reels copper wire, 4 sheets white pasteboard, 4 plain postcards, 4 reels white cotton thread, 1 length latex rubber tubing, 4 each resistors 100 ohms and 10 ohms, 4 support bases, 10 MES bulbs, 8 MES bulb holders,1 wood clamp and 1 wooden block. With instructions.

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

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

A simple form of D.C. motor with 2 pole armature wound with insulated copper wire and a permanent magnetic field provided by a removable bar magnet with a commutator and phosphor bronze brushes connected to 4 mm sockets, open construction, all parts visible.