DescriptionThe Transducers Kit TK2942 provides student assignments covering a widerange of transducers and a number of standard signal processing methods.

The TK2942 range consists of a Measurements Package, containing acomprehensive Instrumentation Module, a Power Amplifier and a Test Rig,plus three self-contained Transducers Kits. The kits are available separately,for use with the Measurements Package, allowing a complete transducerworkstations to be built-up in stages.

Electro-mechanical Transducers Kit TK2941E comprises six lineardisplacement transducers. It is the foundation kit for the TK2942 range andintroduces some basic principles about transducers and the associatedinstrumentation requirements.

The two other kits should be regarded as extensions to it.

Heat Transducers Kit TK2941H provides a heat bar, three thermaltransducers, a reed relay and a bimetal switch together with temperaturemeasurement accessories.

Light Transducers Kit TK2941L contains an optical detector assembly,three photoelectric devices and a selection of optical filters.

The transducers utilise a variety of physical properties, so that in total a verycomprehensive treatment of the subject is achieved. Each transducer is treatedindividually and then, using the measurements package, it is shown how theyintegrate into complete systems. Mathematics is kept to a minimum levelconsistent with that necessary to cover the subject adequately. The coverageis equally suitable for fields of Electronic and Electrical Engineering, ChemicalEngineering, Process Control, Physics and Mechanical Engineering.

The student manual contains twenty-eight assignments, covering the use ofall three kits, each of which include relevant theory and practical discussionsas well as the assignments.

The Transducers Kit, together with all the necessary test equipment, is availableas TK2942-1 Complete Transducers Kit which includes Power Supply 01-100.

Features! Bench-top study of

transducer applications

! Twenty-eight provenstudent experiments

! Text covers theory,practice and industrialapplications

! Employs fifteen commonindustrial transducers

! Inclusive ac and dcinstrumentation sections

! Suitable for mostengineering disciplines

! Repeatable experimentalresults with minimumpreparation time

Transducer Kits TK2942

CoursewareThe manual contains twenty-eightassignments, each having apractical section and an applicationssection giving industrial examplesof the use of the transducerprinciple under discussion.

It is divided into five topic areas:

1. Transducers and systemsutilising variation inresistanceTopics covered are the WheatstoneBridge, amplifiers, liquid depth andresistivity measurements, displace-ment and strain measurement.

2. Transducers and systemsutilising variation incapacitanceTopics covered are the use of theWheatstone Bridge for capaci-tance measurement, variable areaand distance capacitive transduc-ers and their use with an oscillatorand discriminator in FM systems.

3. Transducers and systemsutilising variation ininductanceTopics covered are electro-magnetic induction, variableinductance transducer, mutualinductance transducer, linearvariable differential transformerand the circuit arrangementsrequired for each transducer.

4. Temperature TransducersAn introductory section coversthe use of the heat bar and somegeneral heat theory. The studentis then led through thermocouples,thermistors, the platinumresistance thermometer, thermalreed relay and bi-metallic switch toassignments dealing with on/offand continuous temperaturecontrol systems.

5. Light TransducersAn introductory assignmentprovides a comprehensivegrounding in light theory and theoperation of the light rig.Subsequent topics covered arethree different types of lighttransducer and their spectralresponses.

Appendices provide additionaltheory and information not givenelsewhere in the assignments.

Light TransducersA light source is provided by a lampwhich attaches to the movable platformof the linear transducer test rig.A transducer box contains:-Photoconductive cellPhotodiodePhototransistorThe mechanical arrangement permitseach transducer to be rotated at rightangles to the optical axis of the rig sothat polar response curves can beobtained for each device. By adjustingthe distance between the lamp and

transducer, an output voltage/intensitycharacteristic may be plotted.A set of colour filters is provided. Theseclip over the window of the transducerbox to enable the spectral responses ofthe various transducers to be measured.The theory and operation of each deviceare fully described in the manual.

Tender SpecificationTK2941L. A light transducers kitcontaining three photo-electric transduc-ers, a light source, nine coloured andone heat absorbing optical filters.

Six linear displacement transducers areprovided, each of which mounts ontothe Test Rig. The Test Rig carries amovable platform which supports amicrometer. This is used to provide thetransducer displacement, the wholeplatform being moved to provide largedisplacements. The following lineartransducers are provided:-

Linear Variable ResistorVariable Area CapacitorVariable Distance CapacitorVariable Inductor with sliding rodcarrying a ferrite slug core.Linear Variable DifferentialTransformer (LVDT). This uses asliding core similar to the variableinductor and is used in conjunction witha phase-sensitive rectifier housed in theinstrumentation module.

Strain GaugeIn addition to the linear displacementtransducers, a Probe Assembly isprovided for liquid depth measurement.This is intended to be used in salt water.Variations in depth or salt concentrationvary the resistance between the probes.The resistive transducers are used eitherin a Wheatstone Bridge or in the feed-back loop of an operational amplifier.The capacitive and inductive transducersare used as frequency determiningelements in an oscillator circuit. Theinclusion of a discriminator and amplifierin the Instrumentation Module enables acomplex FM system to be constructed.TK2941E, together with theMeasurements Package TK2941M isavailable as an Introduction toTransducers Kit TK2941.

Electro-mechanical Transducers

Tender SpecificationTK2941E. An electro-mechanical transducers kit containing six linear displacementtransducers, and a probe assembly.

Heat TransducersThe test mount for the temperaturetransducers consists of a heat bar.This is equipped with a heater at oneend and a multi-finned heat sink at theother.

The temperature gradient producedalong the bar is utilised to explore thecharacteristics of a number oftransducers.

These are attached to the bar in thedesired position by a clip. Calibrationis achieved by means of a mercury inglass thermometer dipped into a watertank which may also be clipped to thebar.

An auxiliary heater is provided whichmay be used in conjunction with thepower amplifier to perform closed-looptemperature control experiments.

MeasurementsPackage

Instrumentation ModuleThis contains four separate sectionswhich may be configured to formsub-systems and systems using thepatching leads provided.

Provided for these assignments are:

ThermistorPlatinum resistanceThermocoupleBi-metallic switchThermal reed relay

The manual explains the use of analoguetransducers as temperature measuringdevices together with the use of thethermistor in a continuous temperaturecontrol system. The switching devicesare used to demonstrate on-off controlof a heater.

Tender SpecificationTK2941H. A thermal transducers kitcontaining five thermally operateddevices, a controlled heat bar, thermom-eter and all necessary accessories.

Wheatstone BridgeThis is equipped with selectable ratioarms of 100Ω, 1kΩ, 10kΩ and 100kΩ,a reference potentiometer and adetector short circuit push-button switch.

Operational AmplifierThis module contains a differentialamplifier with switched gains of 1, 10, 100and 1000. The switched-gain amplifier isused as a general purpose amplifier; thedifferential input permitting its use withthe Wheatstone Bridge.

OscillatorThis is designed for use with theinductive and capacitive transducers asfrequency determining elements.The centre frequency is 465kHz.

DiscriminatorA FM discriminator used in conjunctionwith the oscillator module. Also includedare the components for a phase-sensitiverectifier.

The Measurements Package, TK2941M, is shown with the Light Transducers Kit,TK2941L and the Linear Transducers Test Rig in a typical practical assignment.

Power AmplifierA unity gain power amplifier with anoutput capability of 4 watts.

Tender SpecificationTK2941M. A Measurement Packagecomprising an Instrumentation modulecontaining: Wheatstone Bridge, switchedgain, differential amplifier, oscillator with465kHz centre frequency and an FMdiscriminator; a unity voltage gain 4Wpower amplifier module; and a Test Rig.

Specification

Park Rd, Crowborough, East Sussex,TN6 2QR, England.Tel: +44 (0) 1892 653322Fax: +44 (0) 1892 663719E-mail: feedback@fdbk.co.ukWebsite: www.fbk.com

For further information on Feedback equipment please contact: . . . . . . . .

Transducer Kits TK2942 - 7 Printed in England by FI Ltd, Crowborough 0606

Feedback reserves the right to change these specifications without notice. Registered in England number 990620. A subsidiary of Feedback plc.

Instrumentation Module Wheatstone Bridge with reference potentiometer and selectable value ratio arms.Operational Amplifier with selectable gain and differential input.

Oscillator Centre frequency 465kHz.Frequency Discriminator FM operation and on-board phase sensitive rectifier.

Power Amplifier Unity voltage gain. Maximum output 4W.

Test Rig Slide scale micrometer control with 25mm range, 0.5mm/full rotation micrometer.Sub-unit lock for Electro-mechanical Transducers and Optical Detector Assembly.

Electro-mechanical TransducersVariable Resistor 10kΩ, 0.5W linear.Variable Capacitor (Area) 2.5 - 20pF.Variable Capacitor (Distance) 15 - 40pF.Variable Inductor 9Ω, 23 - 81µH.Variable Differential Transformer Primary resistance: 6.3Ω, 140 turns.

Secondary resistance: 2.5Ω, 140 turns.Strain Gauge 2 off, 120Ω resistance.

Conductance Probe Two parallel, conductive, supported rods with flying leads.

Heat TransducersThermal reed relay Operating temp. 45°C. Hysteresis 3°C. Contact rating 10A.Bi-metallic switch Operating temp. 45°C. Differential 5°C.Thermocouple Copper constantan junction approx. 50µV/°C.Thermistor Resistance at 20°C = 2kΩ.Platinum resistance Resistance at 20°C = 100Ω.

Heat Bar 100/240V, 50/60Hz operation.Main heater 50W.Auxiliary heater resistance, 30W (cold).

Light TransducersPhoto-transistor BPX25.Photo-diode RS components.Photoresistor RPY33.Lampholder MBC. 14.4V, 0.1A.Optical Filters 9 slide-mounted. 440, 470, 490, 520, 550, 580, 600, 690, 700nm. 1 infra-red.

Manual supplied Transducer Kit TK2942 covering all three kits. The manual contains 28 assignments, eachhaving a practical section and an applications section giving industrial examples of the useof the transducer principle under discussion.

Power Supply External ±15V @1.5A. The Feedback dc Power Supply 01-100 is recommended.

Dimensions & Weight Instrumentation Module: Width: 295mm (11.6”), Depth: 220mm (8.7”), Height: 72mm (2.8”),Weight: 1kg (2.2lb).

Power Amp: Width and Depth: 107mm (4.25”), Height: 76mm (3”), Weight: 0.45kg (1lb).

Ancillary Test Equipment The following items of standard laboratory equipment are required in addition to the TK2942-001:Function Generator: Sinusoidal, 10V pk-pk, 200Hz to 600kHz; 600 ohm .

Feedback FG601 is recommended.Frequency Meter: Digital, 1MHz range.Oscilloscope: Two-channel, dc coupled, 20MHz.Other equipment: Decade resistance box. Decade capacitance box. Voltmeters, ammeters and

general laboratory glassware.

Tender Specification for TK2942 A Transducer Kit with at least 15 different types of transducers, demonstratingmeasurement of linear displacement, temperature and light. To include instrumentation andpower modules together with all necessary accessories and connecting leads.Comprehensive manual with at least twenty-eight assignments.

Ordering Information Complete Transducers Kit (TK2941E, TK2941H, TK2941L, TK2941M, includesPower Supply 01-100, Function Generator, Timer Counter, Oscilloscope,Capacitance and Resistance Boxes and a Multimeter) TK2942-1

Transducers Kit (TK2941E, TK2941H, TK2941L, TK2941M, includes PSupply 01-100) TK2942-001

Introduction to Transducers Kit (TK2941E, TK2941M, without Power Supply) TK2941

Measurements Package (requires Power Supply) TK2941M

Electro-mechanical Transducers Kit TK2941E

Heat Transducers Kit TK2941H

Light Transducers Kit TK2941L

Power Supply 01-100