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2293 - Precision Resistor 5 Ohms W G Pye & Co England, England The bakelite case contains a precision resistor, used in student electrical experiments. |
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2294 - Octal Valve Socket ST48 Teletron, Australia This item has a mica-filled phenolic shell with metal mount surround and plated brass socket pins of the wrap-around three-point-contact type. |
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2295 - Octal Valve Socket ST38 Teletron, Australia This item has a phenolic shell with flange and mounting joles. The socket pins are plated brass of the 3-contact-point type. |
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2296 - 7 pin Miniature Valve Socket McMurdo, England This item has a phenolic shell with metal surround and mounting holes. The socket pins are 2-point-contact types. |
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2297 - Valve Double Triode 12AT7/ECC81 Miniwatt, England This valve has a miniature 9-pin base. The valve is a VHF double triode typically used in FM frequency multiplier circuits and as a frequency converter. |
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RCA, Usa This is a cold cathode hydrogen-filled 7 pin miniature diode valve. As a regulating tube it delivers a nominal 150V regulated voltage at 5 to 30mA current draw. |
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2299 - Valve Subminiature Triode CV468 Unknown, This is a glass hearing aid valve with 8-pin wire base. When cut to length, the wires will fit an 8-pin subminiature socket. |
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Unknown, China This is a closed cycle external heat engine of a type invented by Robert Stirling in 1816. The working fluid is air, and the working cycle is equivalent to the Carnot cycle that has the highest possible efficiency of any heat engine. Like the Carnot... |
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2302 - Magic Eye DM71 & Socket Mullard, Holland This is a magic eye tube/valve. It has an 8-pin base which fits an 8-pin subminiature socket. The magic eye tube (or valve) for tuning radio receivers was invented in 1932 by Allen B. DuMont. The earlier types were end-viewed (see the... |
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RCA, Usa This is a beam power valve, used as an AF output valve in amplifiers, or in HV power supplies for B/W TV receivers. |
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2304 - Cold Cathode Indicator Tube GR10A Etelco Ltd, England This is a decade counter tube, with neon discharge anodes, which show as a point of light when selected. |
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AWA, Australia This simple AC bridge measures resistance in the range 10 Ohms to 10 MegOhms, 10 picoFarads to 10 microFarads. The expected value is selected by a potentiometer and range switch. Balance is indicated by a magic-eye tube. |
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Paton Electrical Pty Ltd, Australia This meter is laid against a single insulated cable and indicates by induction the current flowing in the cable, whether AC or DC. |
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Noris Chromo, Germany Carbon arcs were run on DC supplies, around 45 to 60 Volts minimum. The rod with a tip crater was used as the positive electrode. In operation it erodes and deposits some carbon on the negative electrode to form a cone. The negative electrode was... |
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Eimac, Usa This item was a capacitor used in a transmitter, probably as part of an aerial tuner. |
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2309 - Medical Stimulation Discharge Electrode Unknown, This is a gas-filled tube. It was used as an electrode in combination with a high-voltage Ruhmkorff coil. The electrode was applied to the skin of the patient, whereupon the the enclosed gas glowed, and the patient was reassured that the electrical... |
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2310 - Multi-Range Current Transformer MRCT University Graham Inst. Co., Australia This current transformer measures the AC current flowing in a circuit, in the range 2.5 milliAmps to 10 Amps. It uses a tapped transformer, with the primary winding in series with the circuit being tested. The unit uses an external 1 mA AC meter,... |
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Unknown, This is used in Radar equipment. The cylindrical glass tube contains 2 convex electrodes attached to brass caps. When the Radar set transmits, the tube discharges across the electrodes, shorting out the receiver input circuit, thus protecting the... |
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2313 - Thermal Circuit Breaker Belling & Lee Ltd, England A bimetallic clip holds a spring-loaded wire. The clip is heated by a surrounding wire, which is in series with the circuit being monitored. When the current in the wire exceeds 250mA, the heat causes the bimetallic clip to open, releasing the wire... |
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Federal, Australia This ceramic unit was mounted on switchboards in homes. It contains two brass wipers which slide into sprung clips. A piece of plated Copper wire of suitable diameter is held by screws between the wipers. This fuse wire is in series with an AC... |
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2315 - Waveguide Variable Attenuation Section Mid-Century Microwavegear Limited, The waveguide throat is 1.5 cm across. A micrometer screw moves the attenuator strip into the throat of the waveguide section. |
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Sprague, Usa An electrolytic capacitor contains two sheets of aluminium foil with one covered in oxide. Thsi forms a dielectric between the foils and insulates them from one another. The thickness of the oxide determines both the capacity and the voltage... |
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GE, Usa This 15 Amp fuse is made of moulded glass with Edison Screw base, containing a short fusible metal strip. |
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2318 - D,Arsonval Meter "Error" Unknown, |
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2319 - Tuning Capacitor Two Gang Roblan, Australia This variable capacitor has two groups of Aluminium plates. The brass spindle may be turned 180 degrees, varying the area of plates facing one another, thus varying the capacity between plates. The range of capacity per gang is around 15 picoFarads... |
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2320 - Styroseal Capacitors 1000V DC Ducon, Australia The three capacitors contain two rolled-up foils separated by Polystyrene dielectric. Capacitors are rated at 1000 Volts DC, values are 0.47, 0.22 and 0.1 microFarad. Polypropylene has supplanted Polystyrene as it is more moisture resistant. |
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2321 - Electrolytic Capacitor ATOM 'LYTIC Sprague, Usa 10 microFarads capacitor for domestic radio receiver power supplies. It is rated at 450V DC, 525V DC surge. It filters the raw rectified AC voltage obtained from a power transformer and rectifying valve. It is polarised in that one terminal is... |
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Unknown, England One coil rotates inside another, varying the total Inductance by Mutual Induction. This was used to match a transmitter driving stage to the grid of the following valve stage. |
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A. Einstein, A letter sent to G.J. Roscoe of Brisbane Teachers' College by Albert Einstein in Berlin in reply to a query on the status of relativity theory. With envelope. |
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1556 - Lead Battery Hydrometer Unknown, Other This hydrometer measures Specific Gravities in the range 1.1 to 1.3 (range given as 1100 to 1300). It consists of a glass float weighted with lead shot that sits in a plastic cylinder, which has a large rubber bulb at the top end to allow... |
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Unknown, This hydrometer is used to determine Specific Gravity of liquids, probably aqueous or alcoholic. The unit floats in the liquid. Weights are added to the scale pan on top, until the marking on the stem is level with the surface of the liquid. Tables... |
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Kimble Glass Co, Usa This hydrometer measures the Specific Gravity of Alcohols, specifically Methanol, Ethanol, and Ethylene Glycol. The float is marked A to K. A table on the cylinder containing the float, gives the SG and type of alcohol corresponding to the letter. A... |
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2325 - Vehicle Battery Hydrometer Vibroc, Australia The glass float is contained within a plastic tube that has a rubber bulb one end and syrings the other end. The bulb is squeezed, the syringe inserted in the battery acid and the bulb released to suck up the acid. The float rises with the... |
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Unknown, Germany This Hydrometer measures Specific Gravities in the range 1.18 to 1.24. This suggests it was probably used for aqueous solutions. |
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2327 - Hydrometer with Thermometer Negretti & Zambra, Germany This hydrometer measures Specific Gravity in the range 1.0 to 1.04 (1000 to 1040). The thermometer has a range 20 to 120F. This suggests the hydrometer was used in water quality studies or with light aqueous solutions. |
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2328 - Hysrometer SG 1020 to 1140 G H Zeal, England Hydrometer for very fine measurements of Specific Gravity, in the range 1.02 to 1.14 (1020 to 1140). |
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The Big Man, Galena (Lead Sulphide) was popularly used in detectors of radio waves, both domestically and commercially, in the early 1900s and later. Frequently considered the best of detector materials until the advent of commercially produced... |
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Unknown, Etched metal fingers on the surface of a circular slab of semi-conductor. Light increases the conductivity of the slab, so current flows more readily between finger sets. |
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National Fabricated Products Inc, Usa The cell is made of semiconductor materials, and comprises a large Silicon PN diode. Light has sufficient energy to induce a voltage difference across the cell by separation of charge. When the wires from the PN junction are connected... |
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2332 - Telegraph Line Insulator Unknown, Australia This insulator was screwed on to a threaded wooden dowel, which was mounted on a wooden or steel pole. Where in Central Australia it was found is not known, but may have supported the 19th Century Overland Telegraph Line from Adelaide to Darwin (... |
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2333 - Valve Output Pentode EL3NG Mullard, Australia This valve was used in domestic radio receivers before WWII. It was an audio power amplifier that drove a loudspeaker. |
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Aristo, Germany This is a student slide rule with standard arithmetic and triganometric functions. |
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2335 - Precision Model III Scintillator Precision Radiation Instruments Inc, Usa The metal container is light-tight and excludes Alpha and Beta radiations. It contains electronics to detect and amplify the output from an external photo-multiplier tube. The unit requires an external power supply or internal batteries in the... |
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Unknown, This is an inverted thermionic triode, with a hot tungsten filament in the centre, a coaxial grid which is positive wrt the filament and a coaxial ion collector plate which is negative wrt the filament. Traces of gas between the electrodes are... |
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Edwards High Vacuum Ltd, England This consists of a heated filament which is cooled mainly by convection. This affects the temperature of the filament, and therefore the electrical resistance of the filament. The filament forms part of a Wheatstone bride for determining the... |
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- Tungsten Halogen Incandescent Bulb Mirabella, China The filament is encloed in a glass tube containing Iodine. Heated Tungsten evaporates, combines with Iodine and is deposited back on the filament. The filament runs at a higher temperature than the standard Tungsten in Argon incandescent bulb. |
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2339 - Pirani Gauge Bridge Model 6/2 W Edwards & Co (London) Limited, England The external Pirani gauge is in series with a constant-current barretter in two adjacent arms of a Wheatstone bridge. Resistances comprise the other two arms. The bridge is initially balanced before starting the vacuum pump/s When the Pirani gauge... |
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2340 - EAI TR-20 Analogue Computer Electronic Associates Inc, Usa The analogue computer preceded the digital computer. It uses electrical voltages to simulate arithmetic operations. The output from a combination of operations is displayed on a Cathode Ray Oscilloscope. This computer has the following blocks: DC... |
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Analite Pty Ltd, Australia This comprises a 40W bulb inside a hammertone finished metal hood with pearl filter to disperse the light. |
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2342 - Selenium Full Wave Three Phase Rectifier Assembly Unknown, This finned assembly of Selenium coated discs, has tag marks White for AC, Red for positive and Black for negative. There are three white tags for the three phases. The Red tags should be connected together as should the Black. |
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2343 - Fuji Microfiche Reader RFP2 Fuji Photo Film Co Ltd, Japan A cover flips up, holding a mirror for viewing the fiche. A fiche is inserted in in a slot in the body of the unit. The fiche is manually moved about, under a lens assembly. Backlighting illuminates the fiche. |
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Unknown, An air spark gap is set by a screw at the base of the unit. A discharge tube of unknown characteristics is in the clip. Both are attached to a ceramic block mounted on a frame. |
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Unknown, Australia This carbon microphone was used by Australian armed services during WWII. It was attached mainly to radio transmitters. The carbon insert is similar to the domestic telephone inserts of the time. |
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General Hearing Co., Usa This is a low impedance magnetic telephone style earpiece. This was used in series with dry cells and a carbon microphone. It was part of an early hearing aid. |
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2347 - Carbon Microphone Insert No 13 AWA, Australia Under air pressure changes caused by speech, the front diaphragm varies the pressure on carbon granules, so varying the resistance of the path through the granules. |
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Paton Elec Pty Ltd, Australia Moving iron meter 5A FSD, used with a current transformer (CT). |
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Paton Elec Pty Ltd, Australia Moving Iron movement, 5A FSD, used with current transformer (C.T.). |
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Unknown, Model can be dismantled to show the structure of the internal eye. |
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Philips, Holland The front face is photo sensitive. Incident image from a lens system charges each pixel. Every 20mS, the face is scanned, line by line of pixels. Charges on each pixel are amplified by a photomultiplier, and form the video signal for TV... |
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Pickett & Eckel Inc., Alhambra, Calif., Usa Pocket slide rule made of magnesium alloy, with the scales printed on. They are: LL1,A,(B,T,S,C),D,LL2 / LL3,DF,(CF,C1F,C1,C),D,L The log log scales are used to raise any number to any power, and the 'pi-folded' scales allow rapid multiplication... |
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R W Paul, England The wire resistor is wound on an insulated cylinder. The slider taps the wire. |
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2353 - Demonstration Bourdon Gauge Unknown, The flat curved tube expands when pressure is applied internally. The tube tends to flatten out. An attachment at the end of the tube moves a sector, which drives a spur wheel and rotates the pointer. The rotation varies as the pressure linearly. |
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Paton Elec Pty Ltd, Australia An external heater is placed in series with an electrical circuit. When current flows the heater heats up a bimetallic juction, creating a DC voltage difference in the junction. The junction is connected to the meter, which is a d"Arsonval movement... |
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Master Instruments, Australia This meter was used with voice and music recording equipment made by AWA. It measures the amplified signal in Volume Units (VU), and deciBels, ref 0dB = 1mW across 600 Ohms. |
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2356 - HT Supply Unit 508, DC Mains Philips, Holland This unit was designed to supply domestic radios from 220V DC Mains. The output was two voltages, one lower voltage for detector and earlier valves, and one higher voltage for audio output valves. The unit has switched potentiometers to supply... |
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Thermos, England This glass vessel is designed to maintain liquids hot or cold for a long period, by reducing the transfer of heat into or out of the liquid. It is a double-walled vessel, with a vacuum between the walls to reduce conduction thru and convection... |
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B&L, Very fine parallel lines have been traced with a diamond stylus across the surface of the glass. There are 150 lines per mm. Thus the lines are 500 nanometres apart. Light reflecting off the suface of the glass is diffracted. Different wavelengths... |
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Brimar, |
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Sylvania GTE, Usa This is an incandescent lamp for a home or military film projector. The filament probably operates in an atmosphere of iodine vapour to reduce tungsten evaporation, and operates at a temperature very close to melting point, thus increasing... |
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unknown, Used for distillation. Historically the apparatus of choice by the Alchemist in his search for the transmutation of base elements into Gold. |
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W. G. Pye & Co., England seven forks. Frequency determined by tine length and thickness. D 576 Hz E 640 Hz F 682.6 Hz G 758 Hz A 855.2 Hz B 960 Hz C 1024 Hz |
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W G Pye & Co, England |
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Max Kohl A. G., Germany Low pressure air is blown through the tapered stem at the base of the pipe. The air exits thru a thin slot and strikes the wooden reed chiselled in the base of the pipe. The reed vibration creates a standing wave in the pipe. The frequency is... |
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2305 - Universal RC Bridge A56048 AWA (A'asia) Ltd, Australia This unit uses a Resistance and Capacity bridge to meaure unknown resistors and capacitors. It can measure resistance in the range 10 Ohms to 10 MegOhms, and capacity in the range 10 picoFarads to 10 microFarads. A 6U5/6G5 magic eye valve is used... |
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