Accredited Museum

Please Note: Not all of the objects on this website are on display at the museum.

CASTELCO CALIPRE BATTERY CHECKER, 1940's

Device for testing batteries, just by lighting a bulb, a good indication of a useful battery because it will test it under load, a bright light would indicate good. Not suitable for chargeable types.

A1457

Air Ministry Ohm Meter, 1932

Air Ministry meter for measuring Ohms from .01 to 0.1 with power connection on the back for a battery and four terminals giving different ranges. It is dated 1932

A1362

SIEMENS ELECTRODYNAMOMETER of 1881

An early current meter was the electrodynamometer of 1881.
It was used until the 1920s when it was replaced by the direct reading meter patented by Edward Weston.
The basic principle was laid out in an 1848 paper by Wilhelm Weber (1804-1891)


Used in the early 20th century, the Siemens electrodynamometer, for example, is a form of an electrodynamic ammeter, it has a fixed coil which is surrounded by another coil having its axis at right angles to that of the fixed coil. This second coil is suspended by a number of silk fibres, and to the coil is also attached a spiral spring the other end of which is fastened to a torsion head. If the torsion head is twisted, the suspended coil experiences a torque and is displaced through and angle equal to that of the torsion head.



Bruce Hammond Collection

A1205

WESTON ELECTRIC METER, 1930's

In 1886 Edward Weston developed a practical precision, direct reading, portable instrument to accurately measure electrical current, a device which became the basis for the voltmeter, ammeter and watt meter. This model dates from the 1930's

Nortel Collection

A1348

UNIPIVOT METER, 1930's

In 1903 Paul introduced a new design of galvanometer, the ‘Unipivot’ galvanometer. It was a robust, easy-to-use, pivoted moving-coil instrument, more sensitive than previous instruments of this type and superior to the widely used moving-magnet instruments. This Instrument dates from the 1930's

Nortel Collection

A1347

TINSLEY CHART RECORDER, 1950's

Chart Recorder with Indian ink type pen, used for measuring current, and driven by a 220vac motor.

A0158

POST WAR POCKET DOSIMETER, 1950's

A radiation dosimeter is a pen-like device that measures the cumulative dose of radiation received by the device. It is usually clipped to clothing to measure the actual exposure to radiation.
Magnifying lenses (a low-power microscope) and an illumination lens, helps to read the dose by aiming the illumination lens at a light source and looking into the device.

For personal use, this is the most useful device to measure radiation, because biological damage from radiation is cumulative.

Dosimeters must be periodically recharged. The dosimeter is usually read before it is charged, and the dose is logged, to chart exposure.
In many organizations, possession of the recharger is limited to health physicists to prevent falsification of exposures.

A0515

EPSYLON TRAINER RADIATION METER No1, 1950's

The unit is not very sensitive,and the scale is not calibrated, the word trainer indicates its nature.
This is a companion model, the trainer is used to teach the use of the Radiac Model No2. Item A1300.
The range is low so it will detect the weak training sources used to simulate radioactive fallout.
See Radiac No2, A1300 for more information.

A1299

No 1 POST WAR CONTAMINATION DETECTION METER, 1954

Radioactivity detection unit, produced after the Second World War as a result of the Cold War period. These units were made on instruction from the government, and supplied to all Councils and Military establishments.
It was expected that in the event of a Nuclear attack, they would be ready to measure contamination levels.

A0513

CONTAMINATION LIQUID HEAD DETECTOR, 1950's

Spare detector head for the contamination meter Item A0513.
For reading liquids

A0514

RUSSIAN POCKET DOSIMETER AND CHARGER, 1950's

Four pocket Dosimeters and charger unit, inside a Bakelite Case.
Used for detection of radiation.
This item was made in Russia

A0979

EK COLE METER SURVEY RADIAC No 2 RADIATION METER, 1955

The scale is not calibrated, The range switch has 4 positions 0 - 3 r/hr / Scale Indicator White (shown)
0 - 30 r/hr / Scale Indicator Blue
0 - 300 r/hr / Scale Indicator Red
Set Zero / White Scale Indicator
The meter can be read while in the carry case and a side flap opens to allow access to the controls.
Measures Gamma - Detects Beta
Beta detection is accomplished by removing the base plate and a barrier plate inside. The unit was used by the Civil Defence Post War. Although referred to as Geiger counters, most CD devices were radiological survey meters capable of measuring only high levels of radiation that would be present after a nuclear event. Required 2X 1.5Volt 1X 9Volt and 1X 30Volt Batteries. The Radiac Survey Meter No 2 or RSM was a 1955 meter which counted the particles produced by radioactive decay. This meter suffered from a number of disadvantages: it required three different types of obsolete batteries, it also contained delicate valves that were liable to failure and it had to be operated from outside the protection of the post.
These were favoured as they had been tested on fallout in Australia after the Operation Buffalo nuclear tests, and remained in use until 1982 by commissioning a manufacturer to regularly produce special production runs of the obsolete batteries.

A1300

DOSIMETER GEIGER COUNTER, 1970's

Found in Belgrade and ended up in the UK
Measures down to point 01 of a Roentgen.

A1294

EKCO BETA/GAMMA DOSE RATE METER Type 95/0030, 1970

Unit used for measuring the strength of radiation over time, not suitable for contamination measurements, this unit will measure the amount of radiation that will be absorbed by coming into contact with the material on test, over one hour. The strength of the object on test is read in Roentgen/Hours, this means that although coming into contact with the object will cause absorption of radiation immediately, its seriousness is only measured if the contact is sustained over a period of time.

A1357

RADIATION METER/ PORTABLE ELECTROMETER, 1950's

Used to test for radiation leakages on X- Ray equipment.

A0117

THEODOLITE DIRECTOR No5 MK1, 1916

Theodolite dated 1916 with broad arrow indicating it has been adopted for military use.

A1134

LARM-U FIRE DETECTOR, 1930's

Early Fire detector using a small plastic disk tensioned by a spring, temperatures above habitable conditions will soften the plastic forcing the steel disks together, creating a circuit which could ring a bell or bells.

A0314

CASSELLA AIR FLOW METER, 1960's

Meter used for measuring air flow Velocity 200-3000 No L 11434

A1020

EARLY THERMOSTAT, 1930's

Thermostat for a variety of uses.
May have been made for a specific piece of equipment.

A0308

EARLY THERMOSTAT, 1930's

Early type thermostat using a sealed atmospheric chamber and a very strong spring.
A lever tilts a Mercury switch

A1013

KELVIN AND WHEATSTONE BRIDGE, 1948

Used for measuring an unknown resistance.
The Kelvin portion enables reading accurately very low resistance (below 1 Ohm). The Kelvin Bridge makes allowances for the high currents used for measuring very low resistances, as heat generated can cause errors.

A1128

HYDROMETER FOR WHISKY BY SIKES, 1960's

Used for measuring the specific gravity of Whisky.

A0260

EARLY MOVING COIL METER, 1900's

Early moving coil meter in wooden box with wall fixing or stand alone on two adjustable feet.

Bruce Hammond Collection

A1210

ROUND AMP METER, 1940's

General industrial meter for measuring power sources, with 270 degree scale.

A0128

GEC ROUND VOLT METER, 1940's

General industrial moving Iron meter for monitoring power sources.

A0127

VOLT AND AMP METERS, 1930's

School Laboratory measuring meters, used in demonstration theatres, and before students were trained to use multi meters, when they started to come into use.
Volt meter is 0 to 10 volts
Amp meter is .5 To 3 amps.

Bruce Hammond Collection

A1191

WATSON KILOVOLT METER, 1940's

0 To 250 kilovolt meter, for Laboratory and College use, designed to be laid flat, as the terminals are underneath.
And WATSON 0 to 20 Milliamp meter,

A0111

WESTON ELECTRIC METERS, 1918

The calibration certificate for the ammeter is for Serial No 30940 ?
The meter shown is Serial No 23602.
The Voltmeter is dated 13 Jan 1920.

British-born American Chemist who revolutionized the Electro-plating industry, founded the Weston Electrical Instrument Company. A prolific inventor who held 334 patents, Edward Weston May 9, 1850 – August 20, 1936 helped revolutionize the measurement of electricity.

Weston's son, Edward Faraday Weston also received several patents regarding exposure meters.

A0975

NEWTON AND WRIGHT BRASS AMPMETER, 1930's

Surface mounting ampmeter for 0-25 amps in brass case.

A0256

CIRSCALE AMPMETER, 1930's

Meter calibrated for measuring direct current up to 300 amps. Requires an external shunt.

A0255

WR MORRIS HOT WIRE AMMETER, 1930's

Hot Wire Ammeters work the expansion and contraction of a piece of wire when heated by an electric current. Although not very accurate and prone to ageing effects of the wire, they were an inexpensive way of indicating currents of over 100 Milliamps.
Smaller current versions would have made the wire too fragile.

A0722

, 1930's

Power moving Iron meter for measuring domestic equipment, volts and amps are measured by inserting this device between the power lead.

Bruce Hammond Collection

A1190

DOMESTIC POWER METER BY SIEMENS LTD, 1930's

Plugged into a lamp socket, the appliance was plugged into the meter ,it then measured the current being drawn.
Used in the days when household power points were rare if not non existent, and electric irons were plugged into the light fitting.
The movement is of the moving Iron type.

A0282

PIFCO ALL IN ONE METER, 1920's

Meter for home workshops, with 5 ranges and 7 terminals, including a top centre terminal.
Advertised in The Wireless World 1932 for 12 Shillings and Sixpence

A0309

PARA VOLT FOB METER, 1920's

Engineers pocket voltmeter. And the original box.
120 Volts Dc could have been the local mains voltage before 1930.

A0301

POCKET FOB WATCH METER, 1920's

Engineers pocket meter, moving Iron type, which looks like a pocket fob watch.
120 Volts Ac or Dc could have been the normal mains voltage before 1930.

A0300

FOB VOLTMETER, 1930's

Pocket meter for engineers.
120 Volts DC could be a normal mains voltage before 1930.

A0299

NADIR MULTI METER, 1930's

Forerunner to the modern Multi Meter

A1093

CAMBRIDGE PORTABLE pH METER, 1940

Moisture content measuring device

A1092

HEILAN MOISTURE METER, 1930's

Early equipment for the measurement of moisture

A1094

SHEATH CURRENT TESTER, 1930's

Used by the GPO for measuring underground cable sheath current to detect breaks

A1096

RESISTOR SUBSTITUTION BOX, 1950's

Substitution boxes are used for temporarily replacing resistors that may be assumed faulty, or inserting a known value of resistance into a circuit and conveniently adjusting the value.

A0107

ADVANCE SIGNAL GENERATOR TYPE E MODEL 2, 1949

Well Known Signal Generator used by the Trustees, and in Radio and Telivision workshops for aligning Radio's and early Televisions during the 1950/60's. Covers 100Kc/s to 100Mc/s in six ranges , Band A : 100 - 300Kc/s
Band B : 300 - 1000Kc/s
Band C : 1 - 3 Mc/s
Band D : 3 - 10 Mc/s
Band E : 10 - 30 Mc/s
Band F : 30 - 100 Mc/s The manufacturers claim it had an accuracy of +/- of 1% over the whole range

A1342

TEKTRONIX OSCILLOSCOPE, 1960's

Large valve type Oscilloscope used in service Laboratory's throughout the world Usually mounted on a steel trolley

A1016

UNIVERSAL AVO MULTIMETER., 1930's

The Universal AVO meter of 1933 Dated 1938. This was the first in the range of these famous instruments, and was replace by the model 40.

Avo Multimeters were the mainstay of the service industry in the 1950's to the 1990's and are still available today, but extremely expensive. The 'Automatic Coil Winder and Electrical Equipment Co.', Douglas Street, London SW1, later renamed to 'AVO Ltd.' (which should not be mixed up with 'Avo International Ltd.)
AVO is well known for it's very solid and reliable measuring instruments, and - coil winding machines.

A0108

AVO MINOR MULTI METER, 1930's

Cheapest of all AVO meters in original case, to change the range you simply re plug the leads.

In 1938 the AVO minor cost 45 Shillings.

A1009

AVO MULTI MINOR MULTI METER, 1930's

AVO is well known for it's very solid and reliable measuring instruments.this unit was less expensive than the larger models, but unlike the Minor had a switch to change the range.

AVO 'Automatic Coil Winder and Electrical Equipment Co'.

A0109

AVO MODEL 7 MULTIMETER, 1950

The model 7 was intended more for electricians and power engineers. The model 8 was better for bench electronic engineers. These meters were the classic instrument for test engineers in the radio and TV service industry for many years.

A1331

AVO MODEL 40 MULTIMETER, 1964

This classic Avometer was introduced in 1939. At 333 Ohms-per-volt not designed for electronic equipment. It was advertised as a 'Power Engineer's' meter. Introduced in 1939 and initially supplied to the Admiralty.

A1332

AVO MODEL 8 Mk4, 1970

In 1970 the Avometer model 8 Mk4 cost £34.80 and the case £5.50. Today the Avometer model 8 Mk7 is £500 plus The AVO Model 8 multimeter reached retirement after 58 years
(24/11/2008)
Possibly the most popular professional multimeter of the 20th Century, the venerable AVO Model 8 has reached retirement: the final Model 8 have left Megger’s Dover factory, where it has been produced since its introduction in 1951. Last off the line the Mk7.

Nortell Collection

A1384

AVODAPTER VALVE TESTER ADAPTERS, 1932

The units are plugged into a receiver between the valve under test, the set is switched on and after a warm up period with the leads connected to a test meter the performance of the valve can be measured.
The four and five pin unit in 1923 cost 25 Shillings and the seven pin unit cost twelve shillings and six pence.

Bruce Hammond Collection

A1263

AVO 160 VALVE TESTER, 1960's

Useful for testing Military valves as well as commercial types. Basically the 'Automatic Coil Winder and Electrical Equipment Co.', Douglas Street, London SW1.
Later renamed to 'AVO Ltd.' (which should not be mixed up with 'Avo International Ltd.)
AVO is well known for it's very solid and reliable measuring instruments, and coil winding machines.

A0103

LAFAYETTE MULTIMETER, 1960's

Amateur large scale multi meter, from the 1960's. Uses obsolete battery for high resistance measurement.

A0956

SONIC BOOM DETECTOR, 1950's

Developed as a prototype to measure sound pressure levels to evaluate damage caused by Military Jets flying over buildings.
New Laws regarding Supersonic aircraft flying over built up areas rendered it obsolete.
Similar units are now used to measure explosions.

A1015

GPO ENGINEERS TOOL BAG, 1930's

Standard Issue GPO engineers tool bag of the period.

A0518

SHORTS GAS INDICATOR, 1900's

Used for measuring the coal gas content in air by atmospheric pressure, and indicated by the percentage of coal gas.
The mechanics of the instrument are identical to that of a normal Barometer.

A0323

MANGANIN WIRE RESISTANCE UNIT, 1930's

Manganin was used in the 1930's as a replacement for Nickel Silver used up until then.
Manganin and Ureka wire was superceded by Nickel Copper and Nickel Chrome Alloys.

A0334

CAMBRIDGE POTENTIOMETER 4 DIAL BOX, 1959

Modern Scientific Bridge with accurate voltage reference for measurement of resistance

A0201

THERMASTER LOW TEMPERATURE INDICATOR, 1950's

Unit for measuring temperature from zero to 100 degrees centigrade.
The knob is turned until the needle centres between increase and decrease.
The temperature is read from the scale attached to the knob.

A0212

GRIFFIN & GEORGE STANDARD CELL, 1950's

The Weston cell, invented by Edward Weston in 1893, is a wet-chemical cell that produces a highly stable voltage suitable as a laboratory standard for calibration of voltmeters. It was adopted as the International Standard for EMF between 1911 and 1990. This cell produces 1.01859 Volts. It is a voltaic cell producing a constant and accurately known electromotive force that can be used to calibrate voltage-measuring instruments

A1406

WESTON NORMALCELL, 1950's

Standard voltage Cell for use with accurate measuring equipment such as the Wheatstone Bridge.

Edward Weston (May 9, 1850 – August 20, 1936) was an English chemist noted for his achievements in electroplating and his development of the electrochemical cell, named the Weston cell, for the voltage standard. Edward Weston was a competitor of Thomas Edison in the early days of electricity generation and distribution.
Weston' son Edward Faraday Weston also received several patents regarding exposure meters.

A0333

GPO EXCHANGE TEST SET 5422, 1960's

Used in exchanges for testing equipment.
Marked DGM ATW 54220 Issue 4

A0044

GPO TEST SET No 36, 1950's

Test equipment used for detecting fractures in under ground lead sheathed cables.

A0030

GPO 37 MIRROR GALVANOMETER, 1954

Galvanometer unit for use with other test gear.
May have originally come from Dollis Hill Laboratories.
And may have been made by H.W.Sullivan Ltd in 1954.

A0076

PO NON REACTIVE SLIDE WIRE AND BOX, 1920's

This piece of equipment is in excellent condition and may have come from Dollis Hill Laboratories.

A0077

GPO 74101D OSCILLATOR, 1950's

This too may have come from the Dollis Hill Laboratories.

A0075

GPO 74101 TRANSMISSION TEST SET, 1950's

Originally may have come from Dollis Hill Laboratories.

A0074

LEEDS AND NORTHRUP SPEEDOMAX "H" CHART RECORDER, 1960's

Valve chart recorder, for measuring and recording on paper information collected by sensors sensitive to voltage or current readings, meaning it could record almost any equipment with a sensor attached to it.

A0957

CAMBRIDGE RESISTANCE BRIDGE CALENDAR & GRIFFITHS, 1887

Resistance Bridge (Collins Patent) with pots normally containing a liquid, using pegs, which when dipped, creates a switch.
Messrs Calendar and Griffith invented their Bridge in 1878, it went on to be used well into the 1930's.

A0976

PO RESISTANCE BANK 375, 1940's

Used by G.P.O. engineers as a reference for resistance measurement.
Type 375

A0942

GLUCK BAROGRAPH, 1960's

Modern example of air pressure measuring instrument in original style case.

A0161

MUIRHEAD D-972-A POTENTIOMETER , 1960's

Direct Current measuring device used for accurate measurement of voltages. all voltage measurements are referenced from a 'Standard Cell' similar to Item A0333.

A0882

CABLE TENSION METER, 1960's

Used by aerial cable engineers, such as the Post Office for telephone and telegraph lines, for tensioning the cable correctly.

A0276

ENGINEERS CLINOMETER, 1940's

Used by engineers for checking gradients on structures.

A0275

RADAR KILOVOLTER HIGH VOLTAGE METER, 1950's

For measuring high voltages, probably a TV tubes high tension, the probe on the left is held on the voltage output to be tested, after the lead is connected to ground.
By adjusting the knob on the right the distance between the two balls is reduced untill the voltage sparks accross the gap, the voltage is then read from the scale.

A0274

WAR DEPARTMENT WHEATSTONE BRIDGE, 1940's

War Department Wheatstone Bridge for the accurate measurement of resistance.
Similar to the Post Office standard Wheatstone Bridge.

A0330

WAR DEPARTMENT RESISTANCE BRIDGE, 1915

Together with a Galvanometer and a standard voltage cell Like Item A0333, clipped into the pillars on the right of the instrument, accurate readings of long lines could be measured.
Can be been wired in a bridge configuration.

A0332

TELEGRAPH BRIDGE AND INSULATION TESTER, 1940's

Bridge and insulation tester used in telephone and telegraphy workshops.
Complete with Tangent Galvanometer.

A0331

LOGOHM MK 6 RESISTANCE BRIDGE, 1940's

A battery operated resistance meter operated in a bridge configuration i,e, with three known resistance it is possible to identify the missing section of the circuit when all components are connected in a circle or bridge configuration. Sets like this were made by many manufacturers in the UK before mass production from Japan and China took over.

A0744

DC4 VALVE AMPLIFIER, 1950's

Laboratory Volt meter with valve amplification providing a very high input resistance.

A0740

GPO EVERTSHED AND VIGNOLES MEGGER, 1923

Megger instrument for measuring very high resistances (leakages), using high voltages created by winding the handle on the end.
Used by the GPO on Telephone lines.

A0582

SURVEYORS TROUGH COMPASS IN BOX, 1970's

Surveyors compass's, which have a needle with small sideways movements and few degree marks. Designed to be small and portable, would be used with maps on site.

A0715a A0715b

MAGNETOMETER, 1900's

Also called a Gaussmeter, after Carl Friedrich Gauss in 1833. It measures the direction and strength of magnetic fields in the vicinity of other affecting objects.

The earth's magnetic field (the Magnetosphere) varies due to influences of rocks and ores in the ground or the interaction between particles from the sun affecting the Magnetosphere. This is an early instrument for measuring these effects. It could be mounted on a long rod and slid along taking readings at precise intervals.

A0257

SHARMAN PIPE OR CABLE FAULT LOCATOR, 1914

Patents 16799 15th July 1914 and 24056 15th Dec 1914 accredited this item to Alexander William Sharman, holder of 40 other electrical and scientific patents.

A transformer like search probe for locating breaks in metal pipes and cables which would be connected to the oscillator output (red lead) while the negative lead is connected to a metal stake which is driven into the ground to provide a return circuit. Headphones can be connected to the search probe or to the accessory search coil.

A0204