Physics

The Pair of Helmholtz coils is used for generating homogeneous magnetic field and for the determination of the specific charge of the electron e/m in conjunction with the dual-beam tube. The coils can be switched in parallel or in series. spring clip on the top crossbar is used to mount the Hall sensor during measurements of the magnetic field. The maximum field strength generated by the coils (~ mT) is approximately 750 times weaker than that produced by an MRI machine (~3 T), which are known to be safe for use by people with medical implants such as pacemakers. For use with RA130505. Requires 0-20 DC A power supply. • Coil Dimensions (Dia.): 300 mm • Coil spacing: 150 mm • Number of turns per coil: 124 • DC resistance: 1.2 ohms each • Maximum coil current: 5 A • Maximum coil voltage: 6 V • Maximum flux density at 5 A: 3.7 mT • Weight: 4.1 kg approx.

The dual beam tube can be used to determine the specific charge e/m from the diameter of the path followed by electrons fired into the tube from perpendicularly mounted gun with vertically aligned magnetic field and observation of the spiral path followed by electrons fired axially into coaxial magnetic field. The dual beam tube is partly evacuated electron tube, filled with helium at low pressure and equipped with both axial and perpendicular electron guns. The electron beams are perpendicular to one another and common deflector plate is provided for both guns. The electron beam source is an oxide cathode heated indirectly via heating coil. The electron paths show up as fine, slightly greenish beam due to impact excitation of the helium atoms. Requires 300 or 500 DC power supply. • Filament voltage: max. 7.5 AC/DC • Anode voltage: approx. 150 V DC • Max Anode current <30 mA • Deflector voltage: max. 50 V DC • Glass bulb: 130 mm dia. approx. • Total length: 260 mm approx.

For mounting all demonstration tubes and the optical equivalent. The tube holder consists of powder-coated cast aluminium with clamping fork made of heat resistant plastic and rotatable by 360°. The base plate contains two boreholes for mounting demonstration Helmholtz coils. Including an anti-skid support with three rubber feet. Weight: 1.5 kg. Supplied without tube. Dimensions 230 x 175 x 320 mm (L x W x H).

Pair of Helmholtz coils for generating a uniform magnetic field perpendicular to the axis of the Teltron D series tubes. Teltron Tube Holder D allows the coils to be configured in the Helmholtz geometry or to produce magnetic fields aligned vertically, or coaxial, with respect to the tube axis. The maximum field strength generated by the coils (~ 10 mT) is approximately 300 times weaker than that produced by an MRI machine (~ 3T), which are known to be safe for use by people with medical implants such as pacemakers. Specifications: Number of turns: 320 Max. continuous current: 1.0 A Max. momentary current: 10 min @ 1.5 A; 3 min @ 2 A Effective impedance: 6 Ω Max. field strength: approx. 10 mT Connectors: 4-mm sockets

For demonstrating the straight propagation of electron beams in field-free spaces by projecting the shadow of Maltese cross on fluorescent screen. Also intended for observing the focusing of electron beams by magnetic fields as an introduction to electron optics. The lower section of the maltese cross has hole 3 mm dia. which makes it possible to ascertain the orientation of the cross's shadow under the influence of magnetic fields. Specifications Max. filament voltage: 6.3 V AC Max. anode voltage: 5 kV Anode current: approx. 0.1 mA at 4 kV To perform experiments using the Maltese cross tube, the following equipment is also required: •1 Tube holder (RA67550) and •1 High voltage power supply 5 kV (115 V, 50/60 Hz) or 1 High voltage power supply 5 kV (230 V, 50/60 Hz) •1 Coil from Helmholtz pair of coils (RA67560) •1 DC Power Supply 20 V, 5 A (115 V, 50/60 Hz) or 1 DC Power Supply 20 V, 5 A (230 V, 50/60 Hz) •1 Bar magnet

Highly evacuated electron tube with focusing electron gun and fluorescent screen inclined relative to the beam axis, so that the path of the beam can be seen and the effects of electric and magnetic fields can be studied. The electron beam can be deflected electrically in the electric field of the built-in plate capacitor, and magnetically by using a Helmholtz coil pair D. By adjusting the electric field so that it cancels the magnetic deflection, it is possible to determine the specific charge e/m and the velocity of the electrons. Specifications: Filament voltage: 6.3 V AC Max. anode voltage: 5000 V Anode current: approx. 0.1 mA at 4000 V Max. capacitor voltage: 5000 V Fluorescent screen: approx. 90x60 mm² Glass bulb: approx. 130 mm dia. Total length: approx. 260 mm

For demonstrating the evidence of the particular nature of cathode rays, establishment of negative sign of charge, the ""electron"" as an atomic particle, concept of ""time-base"", operation of cathode ray oscilloscope, simple Lissajous' figures. The diode gun, tungsten wire ""hairpin"" filament and cylindrical collimating anode, projects narrow beam of cathode rays into the evacuated experimental zone. This beam traverses the sphere to impinge on the luminescent screen in spot about 4 mm in diameter. The narrow beam may be deflected in vertical plane to enter the Faraday cage by using Helmholtz Coils. further and horizontal deflection can be obtained using an Auxiliary Coil, thereby constructing simple cathode ray oscilloscope. All connections are made on the Universal Stand. Specifications Max. filament voltage: 6.3 V AC Max. anode voltage: 5 kV Max. capacitor voltage: 500 V Anode current: approx. 0.1 mA at 4 kV (anode)

Allows GM tube with BNC plug to connect to Scaler Timer Frequency Meter with TNC socket.

This demonstration model facilitates the understanding of how dynamo works, thanks to the open and exposed design. A mounted armature, comprising two coils of copper wire, is rotated about horizontal axis by turning the hand cranked drive wheel within magnetic field, created by the permanent U-magnet supplied with the unit. Mounted on plastic base with LED and two mm sockets for connection to measuring instruments. Drive Wheel Dimemsions (Dia.): 140 mm. Base Dimensions (W x L): 150 x 200 mm.

This unit can be used for variety of purposes to illustrate energy transfers: it can be used to lift mass or stretch bungee cord, and to generate an electrical current when the mass falls again or the bungee cord is released. It can also be turned by hand to generate current. The motor/generator (6-9 V) is mounted on robust metal base, and the gearing of the unit and the sizes of the pulleys have been chosen to enable variety of qualitative and quantitative experiments to be undertaken.

A hand driven pulley coupled to the smaller dynamo pulley by a rubber belt to give step-up ratio, to generate both AC and DC. Electrical output is via 2 pairs of 4 mm sockets (AC and DC) and two LEDs.

Belt for demonstration dynamo AC/DC HE53710.

This kit consists of two tubes (one copper, one plastic) and two discs (a supermagnet and an aluminium disc of similar size). When the supermagnet is dropped down the copper tube, it falls much more slowly than might be expected. The other tube/disc combinations do not show this effect, since eddy currents are only produced using the copper tube and the supermagnet. Tube Dimensions (L): 250mm.

Designed for student experiments in electromagnetism, this U-Shaped Electromagnet encourages students to discover and learn the relationship between electricity and magnetism. Requires standard laboratory power supply, maximum voltage 12 V DC. Weight: 0.3 kg. Dimensions (W x L xD): 100 x 150 x 50 mm.

This apparatus is used to study the effect of number of coils on the strength of an electromagnet. The effect of current on strength of the electromagnet can also be studied. The electromagnet coil has 4 mm sockets and tappings at 100, 200, 300, 400, 500 and 600 turns. A hook on the underside allows paper clips to be attached to indicate the strength of the electromagnet for each variable. A low voltage laboratory power supply is also required.

The Relay Demonstration Unit allows the investigation and study of how a relay functions, in a clear and practical manner. A useful property of this unit is that the circuit powering the coil is easily seen to be completely separate from the circuit switched on by the relay. This is one of the reasons relays are used where safe low voltage circuit can be used to control high voltage circuit. When current flows through the coil an electro-magnetic field is produced. This field attracts the iron armature whose end makes the contact, completing the circuit and illuminating the lamp. When the current is switched off, the contact will open again, switching the circuit off. Specifications: • Control input voltage: 2 V DC • Switched supply voltage: 12 V Max

All the components of an electric bell are mounted on a large panel. All wiring is visible and parts are large in size. Operates on 3-4 volts DC

To demonstrate the relationship between magnetism and electricity. Soft iron U-shaped core and keeper with hook. Dimensions (H x Dia.): 110 x 9 mm.

Useful for cores of electromagnets as soft iron loses its magnetism when the current in the coil is switched off, whereas steel retains some magnetism after the current is switched off. Dimensions (L x Dia.): 200 x 12 mm.

For magnetising and demagnetising ordinary magnets, iron bars etc. Consisting of 250 mm long solenoid wound with insulated copper wire mounted on base with switch and 4 mm terminals. Operating voltage 12 V AC or DC at 6 A. Magnetising by AC or DC. Demagnetising by AC.

The globe is suspended from an electromagnet. This makes the friction very low and the earth will rotate at constant speed for many hours after being spun around. AC adapter included. Dimensions (Dia.): 200mm.

A version of traditional piece of equipment for demonstrating the effect of current flowing through conductor in the presence of magnetic field. Connection is made via the 4 mm sockets attached to the side rails. When current of up to 8 A flows, the crossbar rolls one way or the other under the action of the electro-magnetic force. With clearly labelled poles to the magnet it is easy to demonstrate Fleming's Left Hand Rule.

This current balance apparatus (BIL coil) consists of a printed circuit board coil mounted on a support handle. The board has 2 coils one with 5 turns and one with 10 turns, rated at 2 A. The apparatus can be used to measure the force on current carrying conductor in magnetic field. permanent magnet should be placed on the pan of digital balance (a yoke with 2 ceramic magnets will work) and the BIL coil mounted in vertical plane between the magnets. When connected to low voltage power supply and ammeter, the balance will be deflected and the new reading can be taken. The force on current carrying conductor and field strength can then be calculated.

This demonstration motor comes ready assembled, with an open construction which clearly shows the design working parts of a simple motor. The motor is mounted on a robust wooden base with acrylic end plates with 4mm sockets and comes complete with ceramic magnets and yoke. Requires 1 -3 Volt DC laboratory power supply (not included). Overall Dimensions (L x W x H): 125 x 75 x 60 mm.

This self assembly motor kit is very robust and clearly demonstrates the constituent parts of DC motor.

Spare magnet for EL81440 Motor Kit.

A model of the simplest form of DC electric motor, having 2-pole armature wound with enamelled copper wire, and permanent magnetic field provided by removable bar magnet. The construction of the model is completely open and all components are readily observable. A disc-type commutator is incorporated and external connection to the phosphorous bronze bushes is by means of a pair of 4 mm sockets. The motor operates on 6-8 V DC.

For demonstration of the force on current carrying wire in magnetic field. 270 x 100 x 160mm (H x W x D)

A comprehensive kit for teaching up to 8 students the various aspects of electromagnetism. Containing: Alloy magnets, ceramic magnets, steel magnets, yokes, plotting compasses, hardboard formers, iron filings, double C-cores, clips, rings and split rings, support bases, armatures, axle rods, split pins, rivets, rubber tubing, formers, reels, cellulose tape, copper wire, pasteboard, postcards, cotton, resistors, bulbs, lampholders, clamps, blocks and full instructions.

Kit of parts to build six model motors as in the 'Westminster' electromagnet kit. The Motor Construction Kit enables pupils to build their own motors from scratch. By having to construct motors in this way pupils gain better understanding of the theory behind electric motors. Contents: • 12 'Magnadur' magnets • 6 armatures • 6 mild steel yokes • 6 support bases • 6 shafts • 24 rivets • 12 split pins • 1 reel 0.6 mm PVC tinned copper wire • 2 reels Sellotape • 300 mm tubing, 2.5 mm bore

Shafts (axels) for Westminster Electromagnetic Kit MA91525.

Rivets for Westminster Electromagnetic Kit MA91525.

Split pins for Westminster Electromagnetic Kit MA91525.

These expanded polystyrene balls are used for demonstration experiments with electrical charge. 12 mm diameter.

12 mm x 300 mm.

12 mm x 300 mm.

Nylon friction rods.

This extra-large electroscope is ideal for classroom demonstrations of electrostatic principles such as conduction, induction and coulomb repulsion. light-weight metal vane is used as pointer in the electroscope. The lightweight metal blade deflects when the electroscope plate is charged. transparent scale is provided to measure the angle of the deflection. The front glass window slides up to allow insertion of ionizing material in chamber. This electroscope comes with two accessories: an electrophorus disc and spherical electrode. Dimensions: 248 x 203 x 121 mm.

This pack of electrostatic strips allows students to study charge in different materials for electrostatic experiments. The pack consists of 10 clear polycarbonate strips, which tend to gain positive charge when rubbed with cotton duster and 10 white polystyrene strips, which tend to gain negative charge when rubbed. Suitable for use with our brass wire stirrups.

Pack of 10 brass wire stirrups for use with electrostatic strips.

For charge detection and measurement. Useful for a wide range of experimental applications including charging by induction, Faraday's ice pails, Coulomb's law and capacitance of an isolated sphere. The 3.5 digit liquid crystal display has 13 mm high digits with wide field of view unobscured by trailing leads. The display also provides indication of polarity and low battery. The unit is exceptionally easy to read. Two colour coded 4 mm sockets are located on the sides for maximum convenience and anti-slip feet are fitted to the base. Low operating current gives expected battery life in excess of 500 hours. Housed in a robust, ABS plastic case. Supplied with charge plate, battery and instructions. • Range:0 to 1999 nC • Resolution: 1 nC • Overload: 10 x full scale • Accuracy: ±10% of full scale • Input Resistance: 100 GΩ • Leakage Current: 1pA (10pA max) • Capacitance: 4.7mF

A silk cloth ideal for electrostatic investigations. Dimensions (L x W): 300 x 300 mm.

This Parallel Plate Capacitor demonstrates the working of capacitor; a device which allows the storage of electrical energy in the electric field created between a pair of conductors on which electric charges of equal magnitude, but opposite polarity, have been placed. The apparatus will show the dependence on capacity to the distance between the plates and the nature of the medium between them. Dielectric materials can be placed between the plates for further investigation.

This apparatus allows visualisation of electric fields between various electrode configurations, in a similar way to how iron filings allow visualisation of magnetic fields. It is constructed from transparent acrylic, which allows it to be placed on an overhead projector for class demonstrations but can also be used on white surface for use with visualisers or for direct observation by smaller groups. In order to create electric fields large enough to influence the particles, a high voltage, low current 2-5kV EHT power supply is required. Apparatus includes electrodes, clear acrylic base with 4 mm sockets to clamp electrodes and connect power supply, petri dishes and instructions. Also requires liquid paraffin (PA4452 or PA4454 and semolina (not supplied). Base dimensions (L x W x H): 150 x 150x 65 mm.

A hand driven Van de Graaff generator, which is a very effective unit for introducing electrostatics. The length of the sparks generated is wholly dependent upon the speed at which the user turns the handle but sparks of around 20-30 mm are comfortably achievable. Dimensions (H Dome x Dia.): 400 x 200 mm.

Spare main charge belt for hand driven Van De Graaff, EL101544

Spare hand drive belt for hand driven Van De Graaff, EL101544

A top quality Van de Graaff featuring a motor or hand drive split dome to show how charge is collected in the dome. The generator uses one nylon and one Teflon roller to create double charging effect and sparks up to 10 cm. The 22 cm conductor sphere features a 4 mm socket on the top to accept accessories with a 4 mm plug. For 220/240 V. Dimensions (H x W x D): 560 x 220 x 220 mm. Please note that Discharge Sphere is supplied separately.

Spare charge belt for premium Van De Graaff, EL62550.

Spare drive belt for premium Van De Graaff, EL62550. Dimensions for O-rings: 2.62 x 71.12 mm. 3.0 x 82.00 mm.