PRINTOUT with an input frequency range of47-420 Hz.

ProductsStrip-Chart Recorders

Leeds and Northrup are marketing aseries of strip-chart recorders. TheSpeedomax XL 683 Series X-YLaboratory Recorder offers acombination of features in anelectronic null-balance potentiometerfor bench-top recording of either X-Yor X vs time applications. Calibrationsare directly in millivolts or volts fortesting and analysis and for use with avariety of sensors or analyzers. The XLrecorder balances to a full-scale changein the measured variable on the X-axis(pen speed), within 0.5 sec; on theY-axis (paper speed), within 0.7 sec;accuracy on either span is ± 25% ofspan. Upon completion of a record, apushbutton chart advance lifts the penand advances the chart roll to a new"frame," in correct register with the Ycalibration.

Whenever a continuous record of Xvs time is desired, pushbuttonselection from 1, 2, or 3 chart speeds,or thumbwheel selection of 10 chartspeeds, is available. Weight of the unitis 34 lbs. Price: $1,195.

Leeds and NorthrupNorth Wales, Pennsylvania 19454

Portable Electric KeypunchThe Vari-Punch is a versatile

key-punch which will punch and printon any standard 80-column tab card.Alpha characters can be punchedthrough the use of the hold key andthe condensed alpha keyboard. (Alphais noninterpreted.) The Vari-Punchweighs only 14 Ibs and allows anindividual to create data in both man­and machine-readable formatssimultaneously. At present there arefour models. The Vari-PunchModel 401 (punching only) sells for$675, the Model 402 (punching andprinting) sells for $795, the Model 403(remote punching only) is $77 5, andthe Model 404 (remote input punchingand printing) may be purchased for$895.

VARIFAB, Inc.1700 East Putman AvenueOld Greenwich, Connecticut 06870

Incremental Linear and RotaryEncoders

The Teledyne Gurley Model 8706incremental photoelectric linearencoder is designed for use wherever alinear change in position must be

Joseph B. Sidowski

accurately determined electronically.The encoder is compact and has avariety of options in a standardreading head. Options includebidirectional sensing and one or twozero reference pulses. Either photocellor phototransistor sensing can beprovided. Sense of direction isobtained by producing two signals inquadrature and is accomplished byinserting a phasing system in theoptical portion of the system. Thebidirectional capability and up to twoseparate zero reference points can bepackaged within a I-in. cube. TheModel 8706 encoder is available withpulse counts of up to 1,000 pulses/in.Accuracy of ±. 0002 in. is standard.

The Model 8602-69 IncrementalEncoder is designed to permit theelectrical measurement of length,angle, speed, or position. The unitweighs 2 oz and has a diameter of1.375 in. Pulse counts available fromstandard disks range from 1 to 1,024counts per revolution.

Teledyne GurleyTroy, New York 12181

Digital PrinterThe Model DM-400 Digiprinter is a

medium-speed digital recorder with acapacity of 21 columns. The unit willaccept data from up to three differentsources and printout at up to3 lines/sec (63 char /sec). A total of 50alphanumeric characters and symbolsmay be selected for recording data.Interchangeable plug-in data channelmodules are available with featuressuch as floating decimal point, positiveor negative logic input, data storage,multiplexing, and 10-line decimalinput. A DM-400 with one DM-4507-column programmable data channelmodule is $995. A 21-columnindependent-contacts data channelmodule costs $200.

Keltron Corporation225 Crescent StreetWaltham, Massachusetts 02154

Regulated Power SuppliesTechnipower has introduced the

"Practicals," an all solid-state series ofopen construction power suppliespriced at $49.75 for single units. Theunits feature six voltages (5,6,12,15,24, and 28), dependent on model,regulated ac-dc, remote sensing,short-circuit proof, optionalovervoltage protection, and a 5-yearwarranty. Input voltage is 105-125 V,

Technipower, Inc.Benrus CenterRidgefield, Connecticut 06877

ElectromyographThe mSA Type 14A21-2-Channel

Electromyograph is a newly designedunit available in two versions. Oneversion features a storage cathode-raytube; the other features a conventionalCR T. For each channel, foursuccessive sweeps can remain on thestorage monitor-automatically shiftedin the vertical direction. A built-instimulator supplies single, paired, andtrain pulses via a double-shieldedtransformer output. A latency dial,calibrated in milliseconds, permitsmeasurement of conduction velocitiesfor both sensory and motor nerves.The Electromyograph has a featurewhich allows for the automaticrecording of knob positions directlyon film. The camera uses 10-cmphotographic paper and has 12recording speeds with continuous orinterrupted recording modes.

The London Company811 Sharon DriveCleveland, Ohio 44145

Microtelemetry SystemThe micro AC preamplifier and the

micro FM transmitter are used forchronic electrode recording fromunrestrained animals. The single-endedac-coupled preamp features greaterthan 100-megohm input resistance,less than 5-pF input capacitance, lessthan 5 microV noise, and 0.1-6.5 kHzfrequency response, with the gainselectable at x10, xl00, and x200. Thepreamp weighs 1 g and will mount ona mouse's head. The FM transmittertransmits to any standard FM timerwith AFC. The preamp andtransmitter operate for days onminiature hearing-aid batteries.

Transidyne General Corporation462 Wagner RoadAnn Arbor, Michigan 48103

Galvanometer and Rotary ActuatorThe Series G-700 and G-800

galvanometers are designed for stripchart recorder operations and, moreparticularly, for EEG orelectrocardiogram recording monitors,where unattended operation for longperiods of time are required.Movement is tangent oriented for edgewriting on 50-mm chart width withheated stylus; damping is controlledelectromagnetically to assure optimumsquare wave overshoot and frequencyresponse. The Series G-700galvanometers are of the open loop

Behav. Res. Meth. & Instru., 1971, Vol. 3 (3) 167

Fig. 1. Grason-Stadler 1703 Recording Audiometer described above.

type; the G-800 are closed-loop withposition feedback. Drive amplifiers,available separately, provide dc offset,variable gain, and damping.

General Scanning, Inc.80 Coolidge Hill RoadWatertown, Massachusetts 02172

Recording AudiometerThe Grason-Stadler Recording

Audiometer is designed to implementsimple, rapid, and accurate hearingtests in situations such as those createdby employment screening and theongoing monitoring of hearing acuityin hearing conservation programs. Theunit provides fixed-frequency,pure-tone signal presentations andBekesy-type recording of the S'sresponse. Unique features of the 1703include variable-speed attenuation andautomatic retest at 1 kHz.

To present the test, the operatormerely places an audiogram form onthe chart bed of the audiometer andpushes a START button. The unitthen takes over, presenting the seventest tones in succession, first at the leftear, then at the right ear. At thetermination of the testing, the rightear is rechecked at 1 kHz as a measureof the test validity. Total testing ofboth ears requires about 7lf2 min. If, atany point, the operator should wish tomodify the testing procedure, he candepress a pushbutton which holds thetest at its current frequency. Therecord of the S's threshold is obtainedby a recording pen that moves alongthe hearing chart's X-axis as a functionof time for each frequency. In theabsence of a S response, an automaticattenuator associated with the S

switch increases the sound level in theearphones (to +90 dB HTL max) andsimultaneously moves the recordingpen down along the chart's Y-axis. Inthe presence of a S response, theattenuator decreases the sound level(to -10 dB HTL min) and moves therecording pen up along the chart'sY-axis. Since, at the start of each testfrequency, the sound level is changedmore rapidly than it is after the S'sapproximate hearing threshold isreached, less time is spent attaining thethreshold-with the result that theaudiogram so produced contains moreinformation about the threshold and isless subject to retest variation thanaudio grams produced by othertechniques.

The Automatic RecordingAudiometer is designed with specialattention to reliability, simplicity ofoperation, and permanence ofcalibration. Its performance is wellwithin the Audiometer Specificationsof the American National StandardsInstitute, S3.6-1969.

Price: $1,495, f.o.b. destination,continental United States only (exceptAlaska). Quantity discounts on two ormore units.

Grason-Stadler, Inc.Concord, Massachusetts 01742

CRT Keyboard TerminalThe Model310 CRT Keyboard

Terminal can be used with mostsystems, on-line and off-line. Thedisplay features 132 characters in fourlines of 33 characters each. A 5 by 7dot matrix using a 63-character ASCIIcode set forms the characters. Serialtransmission rate is 3,000 bits/sec;

parallel rate is up to 75,000 char/sec.Indicator lights provide a visual meansof ascertaining power, keyboard, bell,and line feed. Price: $995.

CentronicsOne Wall StreetHudson, New Hampshire 03051

Biomedical Research EquipmentThe Transidyne Window

Discriminator for electrophysiologicalresearch includes a rack-mountregulated power supply frame withprovision for up to eight discriminatorcircuit cards. Each card has an upperand lower voltage level control, a fixedtime window (switchable in or out),and a 10- V 1-msec output pulse. Anoptional discriminator-pulse frequencycard is available, which provides a 0- to1-V analog signal proportional to therate at which pulses are occurring.

The discriminator card has an inputimpedance of 1 megohm, de coupled,and an input level of ±10 mV to 1 V.The time window is 1 msec, switch outon card. Frequency response is de to10 kHz. The output impedance is< 200 ohms. Dimensions:5.5 x 6.5 in.; fits standard 22-pin edgeconnector. The 1261 discriminatorcard is priced at $150; thediscriminator-pulse frequency card is$225; and the regulated power supplyframe is $225.

T r ansid yne 's Microtel emetrySystem has been designed for singleand multiple unit recordings fromunrestrained animals. The micropreamp is packaged in a TO-5 can andweighs less than 1 g. Input is singleended, ac coupled; input impedance isgreater than 100 megohms; and inputcapacity is less than 5 pF. The outputvoltage is ± 2 V, short-circuitprotected, and the gain is x10, x100,x200, selectable. Noise is less than5 microV RMS referred to shortedinput measured over 10 Hz-10 kHzbandwidth. Power requirements: + and- 4.5 V, ±10%. Price of the 1114Micro-ac-Preamplifier is $125.

FM Transmitter No. 1116 is pricedat $125 also. Transmission range is upto 50 ft, and the frequency range istunable over FM band 88-108 MHz.Frequency range for Input 1 is1-100 kHz. Input 2 is an optionalinput for addition of external accoupling for different low-frequencycutoffs. Size: 0.75 x 0.25 x 0.14 in.plus tuning capacitor and coil. Powerrequirement: 9 V.

The Transidyne Model MPS-15Power Supply is a regulated ±15 V desource capable of supplying 75 rnA.Ripple and noise are less than100 micro V at 0-75 mA. The unit hascurrent-limiting short-circuitprotection and an electrostaticallyshielded transformer, as well as both

168 Behav, Res. Meth. & Instru., 1971, Vol. 3 (3)

common and case ground connections.Either the positive or negative outputmay be connected to ground or thesupply may be operated floating at upto 100 V off the power supply ground.Price: $74.50.

Transidyne also marketsmicromanipulators andmicropositioners. The TVC 500Micromanipulator providesthree-dimensional movement with asingle control. X-Y reduction iscontinuously variable from 500: 1 to100:1. The S10 Vertical Positioneradds a 10:1 vertical level reduction,10-mm travel. The TVC 500/S10Micromanipulator with tool holder ispriced at $985. The DIOPMicromanipulator provides X and Ymovements by use of a joystick with10:1 reduction. The S10 providesvertical positioning as described above.The DIOP/S10 Micromanipulator is$197.

Transidyne General Corporation462 South Wagner RoadAnn Arbor, Michigan 48103

Student and Research ApparatusLafayette Instrument Company

recently released a new 160-page 1971general catalog. Various studentdemonstration and researchapparatuses are described.

Lafayette Instrument CompanyP.O. Box 1279Lafayette, Indiana 47906

Magnetic Card Processor forMinicomputers

The CPC 5500 Magnetic CardProcessor has the following specs:words/card, 512 (1,024 characters);bits/word, 16; words/block, 128;blocks/card, 4; input hopper capacity,500 cards; output stacker, 1,000 cards;read/write speeds (250 Hz), 128 wordsat 2.15 sec, 256 words at 2.80 sec, 384words at 3.45 sec, and 512 words at4.10 sec.

Data is stored on 16 tracks, andfour tracks are read one at a time.Each block of four tracks has itsunique address. The card is oxidecoated on the data storage side, butthe reverse side can be written ortyped upon for identification. Price ofthe CPC 5500 with interface for theData General Nova minicomputer is$5,000. A PDP-II interface will beavailable shortly.

Computer Property CorporationSeven Dey StreetNew York, New York 10007

Cassette Loader for MinicomputersThe Infotec Tape Cassette Program

Loader is capable of rapidlybootstrapping programs into corestorage. With Infotec-suppliedsoftware, the device can search forspecific programs from a programlibrary which is always on-line.Standard programs supplied with thesystem and the manufacturerscomparison of the average cassette vsASR loading time are as follows:

Cassette ASR-33

ASSEMBLER 2min 13 minEDITOR 1 min 10 minFOCAL 2 min 13 minFORTRAN 3 min 25 min

The DEC-supplied series of diagnosticprograms are available on cassette also.

The unit weighs less than 10 lbs andrequires less than 5 min to connect.Cost, including interface and programlibrary, is $400.

Infotec, Inc.70 Newtown RoadPlainview, New York 11803

Multipurpose Perceptual DeviceResearch Media, Inc., is marketing a

three-in-one perceptual device whichcan be applied to the demonstration ofbasic psychophysical methods. Theunit allows for individual control oftwo light sources which makes itpossible to determine the differentialthreshold for visual brightnessdiscrimination, employing variousintensities of the standard stimulusmember of the comparison pair.

The beta movement can bedemonstrated by controlling the lightsource intensity, proportions of light(ON) and dark (OFF) phase times. Thedevice also allows for the study ofcritical flicker fusion frequency.

Cost of the multipurpose perceptualdevice, Model PR-27, is $435. Thedeveloper is Dr. R. Fried, HunterCollege.

Research Media, Inc.4 Midland AvenueHicksville, New York 11801

Blood- Pressure TransducerThe Model MP-I0 Implantable

Blood-Pressure Transducer is aminiature unit designed expressly forlong-term chronic measurements inunanesthetized animals. The pressurerange is -50 to 300 mm Hg; overpressure is 500% F.S. Input impedanceis 1.5 k ohms nominal, and excitationlevel is 10 V. A skin button connectorallows for easy application and simpleinterconnection to a recording system.The manufacturer and model of yourrecorder should be stated whenordering.

Micron Instruments, Inc.1519 Pontius AvenueLos Angeles, California 90025

Miniature 10-Channel RecorderThe Model 2755 Series Miniature

10-Channel Event Recorders weigh4 Ibs and require a panel cutout ofapproximately 3.58 in. square. Theoverall depth of the recorder is9.10 in. A slide switch allows the userto select one of the two built-in chartspeeds. High speed is six times the lowspeed. Interchangeable gearboxes areavailable which provide speeds from20/120 mm/h to 600/3,600 mm/h.Other speeds may be ordered. A largeselection of ac and de pen drivevoltages are available from stock.Motor drives are available foroperation on as low as 2-3 V de at10 rnA, up to 240 V ac, 60 Hz. Coatedpressure-sensitive paper produces a redtrace. Price of the unit, with two rollsof chart paper, is $175.

Simpson Electric Company5200 West Kinzie StreetChicago, Illinois 60644

BriefsAlphanumeric Display

Madatron Corporation of Shippany,New Jersey, is marketing analphanumeric display system capableof presenting an unlimited number ofsets of numerals, symbols, and letters.Up to 128 10-letter words can bedisplayed in a 10- or 20-position array.The display module consists of anumber of %-in. CRT units whichprovide characters % in. high. Lifeexpectancy is advertised as 25,000 h.

Data input to each decoder iscompatible with most logic systems.The character generator is a read-onlymemory drum preprogrammed for astandard character array. Thegenerator produces 48 or 64 charactersper CRT and can be used with a largenumber of CRTs. The memory drumweighs less than 1 oz and is listed ascapable of operating continuously(without lubrication) for 10 years. Thenormal operating speed can beincreased from 1,800 r/min to2,25 0 r /min, which will increasecharacter repetition rate to 37 r/secfrom the normal 30 r/sec. Prices varyfrom $25 to $100 per CRT position.

Project-a-LiteWhere a source of intense light is

needed, the Project-a-Lite enables theE to convert a Carousel Projector intoa 500-W fiber optic illuminator in30 sec. To convert, one needs simplyto switch lens barrels. The adapter willaccept any standard fiber optic lightguide. Price with one adapter, one

Behav. Res. Meth. & Instru., 1971, Vol. 3 (3) 169

base, and one FD4 3-in. light guide:$71.90.

DYONICS71 Pine StreetWoburn, Massachusetts 01801

Tape Recorder/ReproducerThe Newell DI-100 C Digital

Recorder features both incremental(500,000-word storage) andcontinuous modes (16,000,000-bitstorage), and transfers data at96,000 bits/sec. The unit has singlecharacter backspace capability,simultaneous two-track recording forerror detection and correction, a2-msec start time for incrementalmode, and a 40-msec start/stop time(120 ips) continuous mode.

The DI-100C cartridge(3 1/ 2 X 3Ih in.) contains 430 ft of Vi-in.tape for the storage capacities notedabove. Only one moving part, thecapstan, provides tape drive power inboth directions. Since the capstan rimis in direct contact with both taperolls, no tape guides or tension armsare needed. Since there is only onedriven wheel, supply and take-up rollsare merely idlers and require no powersource. No extra motors, complexbraking systems, or tape tensioningarms are required. Physical size is8% x 8% x 22 in., with a completeweight of 301bs. Price: $2,500.Without digital read/write electronics,the unit is $1,650. All units carry aI-year parts warranty.

Newell Industries795 Kifer RoadSunnyvale, California 94086

Electronic ShutterThe ES-100 Electronic Shutter

System offers three unique functions:a power density or incident powermonitor calibrated in microVjcm", anelectronic shu tter with continuouscoverage from 1/128 to 2,048 sec, andan integrating exposure controlsystem. The system will operate overthe entire visible spectrum. The cost ofthe ES-100 system is $1,285, completewith shutter, detector, cables, stands,and electronics package. TheModel ES-6 Electro-MechanicalShutter sells for $195.

Jordon Engineering Associates145 Enterprise DriveAnn Arbor, Michigan 48103

Eye MovementsThe Mirsky Eye-Movements

Monitor consists of an eyeglass sensorassembly and an auditory monitor.The unit is sensitive to lateral eyemovements for amounts as small as2% deg. Price: $325.

Stoelting Company424 N. Homan AvenueChicago, Illinois 60624

Minicompu tersThe popularity of minicomputers is

accelerating abroad. Although a goodshare of the overseas market isdominated by American firms, anumber of machines are"home-grown" and several are beingmarketed in the U.S.

Most of the foreign minicomputermanufacturers are listed below.Additional information covering themachines may be obtained by writingthe firms directly.

Arcturus Electronics, Ltd.21c Ashley PlaceLondon, S.W.1, England

The 18-C has a 4k memoryexpandable to 64k with a2.4-microsec add time. Basic wordsize is 16 bits; memory consists of18 bits with parity.

Ateliers de ConstructionsElectriques de Charleroi (ACEC)Div. ESB. P. 4Charleroi 1, Belgium

Model ACEC 92 is a 16-bit processcontrol computer with 4-64kmemory and 6-microsec add time.

A/S Norsk Data-ElectronikkOkernveien 145Oslo 5, Norway

NORD-2B has a 4-16k corememory. Word size is 16 bits; addtime is 2.4 microsec.

AEG-TelefunkenIndustrielle DatenverarbeitungPostfach 606453 Selingstadt, West Germany

The 60-10 process computer isupward compatible with thecompany's larger machines. Basicword size is 12 bits plus parity. Corememory is 4-32k and add time is4.5 microsec.

Computer Technology, Ltd.Eaton RoadHemel HemsteadHertfordshire, England

Modular One has a core memory of4k expandable to 56k and an addtime of 0.95 microsec. Word size is16 bits.

Digico Ltd.St. Michael's HouseNorton Way South

LetchworthHertfordshire, England

D i gico Ltd. markets threeminicomputers. The Digiac is a16-bit drum storage unit with a 4kmemory. The Micro 16 and theMicro 16P are 16-bit computerswi th basic 4k memories; theModel 16 is expandable to 64k, the16P to 16k. Add time for the latteris 4 microsec; for the Micro 16, addtime is 14 microsec for 2-microsecstore and 20 microsec for6-microsec store. A lk ROM isavailable for the 16-P.

Elbit Computers Ltd.P.O. Box 5390Haifa, Israel

The Elbit 100 has a 1-4k memorywith a 7.2-microsec add time. Basicword size is 12 bits.

Ferranti, Ltd.Automation Systems DivisionSimonswayWythenshaweManchester, M22 5LA, England

The Argus 600 has an 8-bit wordsize and a 1k memory expandableto 8k. Add time is 9.2 microsec.

Fijitsu Ltd.Furukawa Sogo Building6-12 Chome ChiyodakuTokyo, Japan

F ACOM-R is a 16-bit, 1-32kmachine with 6-microsec add time.

Heinrich DietzPostfach 48/8433 Muelheim (Ruhr)West Germany

The Mincal513 is afixed-programmed computer; theModel 523 is core-based. Basic wordsize is 19 bits plus parity with a corememory of Vik (32k). Add time is90 microsec. The Mincal Models 4E:and 4N are similar but expansioncapabilities differ, as do the prices.

Hitachi, Ltd.International Sales DivisionComputer SectionNippon Building6-22 Chome Otemachi,Chiyoda-kuTokyo,Japan

HITAC-l 0 has a standard 4k corememory expandable to 32k with2.8-microsec add time. Basic wordsize is 16 bits plus parity.

170 Behav. Res. Meth. & Instru., 1971, Vol. 3 (3)

Transformer Color CodingThe EIA color-coding system is used

for identifying lead wires ofAmerican-made transformers. Codingis as follows:

- B+ or power- Collector or plate- Collector or plate- Base or grid- Ground or bias or v.c.- Grid or base or v.C.

Audio Transformers

Power Transformers

- Primary-High voltagesecondary

Red/yellow - High voltage centertap (C.T.)

Yellow - Rectifier filamentGreen - Tube filamentGreen/yellow - Filament C.T.Brown - Extra filamentBrown/yellow - Extra filament

BlackRed

RedBlueBrownGreenBlackYellow

Minicomputer SemiconductorMemories

Some manufacturers ofminicomputers are switching tosemiconductor main memories to gaincomputational speed. Of course, onesignificant difference betweensemiconductor memory and core isthat the semiconductor type isvolatile. With minicomputers, data incore is sometimes expected to survivea shutdown, so most manufacturersoffer a power-fail restart, often as anoption. The power-fail restart controlsan orderly shutdown if power is

in New York, DEC introduced a newgroup of options for computer logictraining with either the PDP-12 or thePDP-8 computers. These consisted ofan access panel, a connector block thatenables students to test newlydesigned circuits, a laboratory guide,and a logic design laboratory. Thelaboratory contains electroniccomponents and tools for students toassemble a series of computerinterfacing modules.

The TD8/E is a relatively newDECtape control contained on a singlequad flip-flop chip module. The unitplugs directly into the PDP-8/EOmnibus and handles the TU56M orTU56MH DECtape transports. TD8/Ecost with a dual TU56M unit is$5,000. The listing is $3,000 with asingle TU56MH transport.

The DEC terminal VT06(alphanumeric) is a CRT display andkeyboard with 1,800-character imagearea. The unit is designed for all PDPsand is listed at $4,900.

News from DECDigital Equipment Corporation of

Maynard, Massachusetts, displayedtheir 10,000th DEC PDP-8minicomputer at the recent Fall JointComputer Conference in Houston. Themachines were manufactured over aperiod of only 6 years. For the 60days prior to the conference, thecompany announced that 700 DECcomputers had been delivered.

Approximately 500 16-bit PDP-llcomputers had been delivered over a6-month period.

At the recent (1971) Physics Show

Used ComputersThe American Used Computer

Corporation (15 School Street,Boston, Massachusetts 02108) isadvertising used computer systems.The Digital Equipment CorporationPDP-I0 is listed at 20% less than theoriginal price.

Zuse K.G.Grosse Industriestrasse 19/20643 Bad HersfeldWest Germany

The Z43 is a 16-bit-word machinewith a basic 8k memory expandableto 64 k. A desk model is limited to32k. Add time is 1.96 microsec.

generally tied into the company'stelemetry system.

Unicomp GesellschaftSinnrain Strasse 157500 Karlsruhe 41West Germany

The 201 is a 12-bit data-word/20-bitcommand-word computer with a IAkexpandable to 16k memory. Addtime is 8 microsec (core) and6 microsec (2 microsec ROM).

Memocon-16 has a 4-16k memory,16 bits, plus parity word size, and a7-microsec add time.

Yaskawa Electric Mfg. Co., Ltd.Otemachi BuildingChiyoda-kuTokyo,Japan

Surface Charge TransistorsGeneral Electric scientists have

developed a surface charge transistorwhich stores information on a siliconchip at densities of a million bits/sq in.The semiconductor contains a sourceand a receiver electrode separated by aslit and a third electrode (transfergate). The latter overlaps the slit andonly a small charge on the gate cancontrol much larger charges across thesurface charge transistor. The unit is sosmall that a typed punctuation periodcould cover several hundred.GP-16 is a 16-bit-word machine

with a 4- to 32k memory and a4-microsec add time.

The Minic-M6901 has a 1k, 4k, or8k memory expandable to 65k andan add time of 4 microsecminimum. Basic word size is 8-bitbytes.

Marconi-Elliot Computer Systems Ltd.Elstree WayBorehamwoodHertfordshire, England

Marconi-Elliot 903 has an 18-bitword size and an 8k memoryexpandable to 131k. Add time is24 microsec.

The NEAC-M4 is byte oriented.Variable word lengths are 8, 16, 24,or 32 bits. The memory is 4-32k,with an add time of 4.5 microsec.

Micro Computer Systems Ltd.1 High StreetGodalmingSurrey, England

The Model 101 microprogram dataword size is 12 bits, with instructionwords at 18 bits. Add time is9 microsec for the 12-bit word andthe core memory is Ihk expandableto 16k. Macro instructions areoffered also. The computer is

Basic word size of theOKITAC-4300 is 16 bits plus parity.Add time is 3.84 microsec for a corememory of 4-32k.

The Mulby is a 4-60k machine with8-bit bytes. Core add time is3 microsec; ROM add time is0.5 microsec.

Krantz Electronik GMBH & Co. K.G.Postfach 99051 Aachen, West Germany

Nippon Electric Co., Ltd.Industrial Automation Division33-7 Shiba 5 Chome, Minato-kuTokyo, Japan

Selenia S.p.A.Automation DivisionVia Tiburtina Km. 12,40000131 Rome, Italy

OKI Electric Industry Co., Ltd.10 Shiba Kotohira-cho,

Minato-kuTokyo, Japan

Siemens CorporationBereich Mess- und ProzesstechnikPostfach 21-807500 Karlsruhe 21West Germany

Behav. Res. Meth. & Instru., 1971, Vol. 3 (3) 171

turned off or if it fails. The restartresumes on the existing core content.

In spite of semiconductor memoryvolatility, manufacturers apparentlyforesee no serious difficulties and state

that critical data can be written onto anonvolatile medium with a plannedshutdown. Where a need exists toprotect main-memory content throughan outrage, a mixture of core and

semiconductor memory is suggested.Another approach is that used withlarge control computer systems, i.e. toprovide short-term emergency powerto capture crucial memory content.

Fig. 2. A diagram of the barrier-gatecombination.

composed of .63-cm brass rods spaced1.9 em apart, center to center, islocated 43 cm from the top of thebox.

The box is equally divided into twocompartments by a .16-cm stainlesssteel combination barrier andguillotine gate. A diagram of this unitis shown in Fig. 2.

The barrier-gate unit is constructedby first punching a 7.5 x 15 emoval-shaped hole in a 15 x 91 cm pieceof .16-cm stainless steel so that the

assure the discrete trial nature of thesituation. The problem lies in theconstruction of a barrier-gatecombination which S cannot use toescape the shock. After numeroussuccessive approximations, we havedeveloped an apparatus which is easilyconstructed and has functioned wellthroughout work on several hundredanimals. Ss have not learnedtechniques for using it to escapeshock.

A diagram of the entire apparatus ispresented in Fig. 1. The box is 66 cmlong x 15 cm deep x 89 ern high. Theback and ends are of wood, paintedbrass color; the front is of .63-cm clearPlexiglas. The back and ends of thebox are covered with brass sheeting toa height of 23 em above the grid. Thisserves to discourage Ss from standingon a single bar and leaning on the wallto escape shock. The grid floor,

\ ~ I' l-=..-"\,, '\'

_==i"""""':"" 11\ \ \,', \ \ I'I I .. \ \ ,\ I,

. "/,, I " \ '\ i 'I

i;111,\, :1) II (~ , I, \\ I \I I ''J I ,'~ ~ I \,

\I'J( i. \" I' Ir I ,; I: ;11 \ \\ J

" J' '!\ " : \,., ", " , J', , I \ "

JII ,I I '\, ',! ,I,ill \ I . \ , \, I I,~ \ ,,' I '.

A shuttleboxfor use with rats

FRANK C. LEEMINGand

JOHN W. PILLEY*Memphis State University

Memphis, Tennessee 38103

An ideal apparatus for the study ofnegative reinforcement in a discretetrial situation is the shuttlebox. Themain problem encountered in theconstruction of this apparatus is toprevent S from escaping shock in waysother than that specified by E. Themost frequent area of difficulty is inthe barrier and gate separating the twocompartments. The presence of thebarrier is desirable since it increasesthe likelihood that S will make arelatively discrete response. The gate isnecessary to prevent retracing and to

Fig. 1. A diagram of the shuttlebox with the barrier-gate combination in a *Now at Wofford College, Spartanburg.partially raised position. S.C. 29301.

172 Behav, Res. Meth. & Instru., 1971, Vol. 3 (3)