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PDF Content Summary: Model 600A Electrometer Instruction Manual Contains Operating and Servicing Information WARRANTY Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment. Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batter- ies, diskettes, and documentation. During the warranty period, we will, at our option, either repair or replace any product that proves to be defective. To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, vansportation prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days. LIMITATION OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leak- age, or problems arising from normal wear or failure to fallow instructions. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES. NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRU- MENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POS- SIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAM- AGE TO PROPERTY.

Safety Precautions The following safety precautions should be observed before using this product and any associated instrumentation. Although some in- struments and accessories would normally be used with “on-haz- ardous voltages, there are situations where hazardous conditions may be present. This product is intended for use by qualified personnel who recog- nize shock hazards and are familiar with the safety precautions re- quired to avoid possible injury. Read the operating information carefully before using the product. The types of product users are: Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equipment is operated within its specifications and operating limits, and for en- suring that operators are adequately trained. Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the instm- ment. They mut be protected from electric shock and contact with hazardous Iive circuits. Users of this product must be protected from electric shock at all times. The responsible body must ensue that users are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product users in these circumstances must be trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000 volts, no conductive part of the circuit may be exposed. As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multimeter measuring circuits (e.g., Keithley Models 175A, 199,2000,2001,2002, and 2010) are Installation Category II. All other instruments’ signal terminals are Installation C&gory I and must not be connected to mains. Do not connect switchjng cards directly to unlimited power circuits. They are intended to be used with impedance limited sources. NEVER connect switching cards directly to AC mains. When co”- netting sources to switching cards, install protective devices to lim- it fault current and voltage to the card. Maintenance personnel perform routine procedures on the product to keep it operating, for example, setting the line voltage or replac- ing consumable materials. Maintenance procedures are described in the manual. The procedures explicitly state if the operator may per- form them. Otherwise, they should be performed only by service personnel. Service personnel are trained to work on live circuits, and perform safe installations and repairs of products. Only properly trained ser- vice personnel may perform installation and service procedures. Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks 01 test fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect that hazardous voltage is present in any ““known circuit before measuring. Before operating an instrument, make sure the line cord is connect- ed to a properly grounded power receptacle. Inspect the connecting cables, test leads. and jumpers for possible wear, cracks, or breaks before each use. For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting cables or jump- ers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers. Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always make measurements with dry hands while standing on a dry. insulated surface capable of withstanding the voltage being measured. The instrument and accessories must be used in accordance with its specifications and operating instructions or the safety of the equip- ment may be impaired. Do not exceed the maximum signal levels of the instruments and ac- cessories, as defined in the specifications and operating informa- tion, and as shown on the instrument or test fixture panels, or switching card. When fuses arc used in a product, replace with same type and rating for continued protection against fire hazard. Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground connections. IF you are using a test fixture, keep the lid closed while power is ap plied to the device under test. Safe operation requires the use of a lid interlock. Ifa@ screw is present, connect it to safety eanh ground using the wire recommended in the user documentation. Then symbol on an instrument indicates that the user should re- fer to the operating instructions located in the manual. Then symbol on an instrument shows that it can source or mea- sure IO00 volts or more, including the combined effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these voltages. The WARNING heading in a manual explains dangers that might result in personal injury or death. Always read the associated infor- mation very carefully before performing the indicated procedure. The CAUTION heading in a manual explains hazards that could damage the instrument. Such damage may invalidate the warranty. Instrumentation and accessories shall not be connected to humans. Before performing any maintenance, disconnect the line cord and all test cables. To maintain protection from electric shock and fire, replacement components in mains circuits. including the power transformer, test leads, and input jacks, must be purchased from Keithley Instru- ments. Standard fuses, with applicable national safety approvals, may be used if the rating and type are the same. Other components that are not safety related may be purchased From other suppliers as long as they are equivalent to the original component. (Note that se- lected pans should be purchased only through Keithley Instruments to maintain a.ccuracy and functionality of the product.) IF you are unsure about the applicability of a replacement component, call a Keithley Instruments office for information. To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior of the instrument only. Do not apply cleaner directly to the instrument 01 allow liquids to enter or spill on the instrument. Products that consist of a circuit board with no case or chassis (e.g., data acquisition board For installation into a computer) should never require cleaning if handled according to in- structions. If the board becomes contaminated and operation is af- fected, the board should be returned to the factory for proper cleaning/servicing. Rev. ?.I99

MODEL 6OOA ELEKX'ROMFt73R TABLE OF CONTEmTs Title Pa3 section I. - Introduction. ........................ 1-l Section II. - Specifications ....................... 2-1 Section III. - Operation ......................... 3-1 A. Controls andTerminals ....................... 3-l B. Preparing the Instrment for Operation ............... 3-2 C. Measuring Voltage. ......................... 3-2 D. Measuring Current. ......................... 3-2 E. MeasuringOhms ........................... 3-3 F. BatteryCheck. ........................... 3-4 G. Using Extenal Indicators. ..................... 3-5 R. Misce.Ll.aneous Applications ..................... 3-5 I. Zero Center Operation. ....................... 3-6 Section IV. - Circuit Discussion ..................... 4-l A. Voltmeter .............................. 4-l B. Ammeter.. ............................. 4-2 C. Ohmmeter .............................. 4-3 Section V. - Accessories ......................... 5-l Section VI. -Maintenance. ........................ 6-1 section VII. - Replaceable Parts List. .................. 7-l Voltage-Resistance Diagram ....................... 7-3 Schematic Diagram. ........................... 7-5 ............................. La&Page ?+l'he yellow Change Notice sheet is included only if the instrument contains mod- ifications which affect the instruction manual. 0962~ i


with The Keithley full-scale Model ranges 600A of Electrometer 0.01, 0.03, is 0.10, an ultra-high 0.30, 1.0, impedance 3.0 and 10 voltmeter volts. by but 600A unwanted The input means maximum also is resistance not pickup. of can the ,only input be used shunt may appropriate resistance where be resistors varied a high for is in built greater measurement decade input into than impedance steps the 10lh in from instrument. high-impedance would ohms; one merely ohm in addition, to Thus, 1011 circuits, introduce the ohms the ampere and largely larly The g,"",;"';"t"~ of input the 10x 6OOA of on 6OOA. full eliminates scales. may the the,more ;,33 scale. be voltmeter Normally, used Two istor ampere sensitive the This as current through input shunted a current &decade ranges, direct-reading ranges. measuring drop from the is negative and determined range current input increases methods ammeter is to feedback measuring covered ground. by are measuring measuring from available can in resistor. Alternately, 3 be overlapping amperes applied speed, the to voltage the to This particu- to lo-l3 3x on user the With The ventional for 600A current a guarded measures ohmmeters, and input, voltage 10K information to its readings. 1012 range ohms is is extended full presented scale to wit on 10 the P 3 a ohms. two-terminal linear Unlike scales input. con- used As 100. factor a dc The in preamplifier, excess continuing of 100 stability the on 600A any range. has of the gains gain of is 0.1, assured 0.3, bv 1, a 3, feedback 10, 30 and pen of lo- The 17K. output recorder or SO-mv Thus, is amplifiers, outputs minus the outputmay 1 for volt, or servo-rebalance the open be output used circuit, for may recorders. with driving be shunted an internal oscilloscopes down resistance to provide or NOTE

D704R WHEN When bracket rear PLACE and circuit screw panel SHIPPING the THE board (Keithley Model may BRACKET with be THE (PC-29). 600A a removed TO Part #I6 INSTRUMENT is FIRMLY x No. shipped 13766A) from sapports the factory, the printed an angle S/16 The after bracket SUPPORT sheet TO the ANOTHER metal Model THE is fastened PRIBTED DESTINATION, screw. 600A is The CIRCUIT to received. the bracket RE- BOARD. 1-l


MODEL 600A ELECTROMETER SECTION II - SPECIFICATIONS SPECIFICATIONS & A VOLTMETER: RANGE: 0.01 volt full scale to 10 volts in seven lx and 3x ranges. ACCURACY: 'r2% of full scale on all ranges exclusive of drift. ZERO DRIFT: Less than 2 millivolts per hour after l-hour warm-up. INPUT IMPEDANCE: Greater than 1014 ohms shunted by 30 picofarads. be selected in decade steps from 1 ohm to 101~ ohms. Input resistance may & & AMMETER:

RANGE: LO-l3 ampere full scale to 3 amperes in twenty-eight lx and 3x ranges. ACCURACY: MLJLTIPLIER 23% of Switch full setting; scale +5% on cf 3-ampere full scale to lo-lo on 3 ampef~lr::g;;~13 x 10 using ampere smallest ranges. available GRID CURRENT: Less than ~5 x LO-l4 ampere. fi & OHMMETER: RANGE: LO4 ohms full scale to 1013 ohms in nineteen linear lx and 3x ranges. ACCURACY: Switch setting; 23% of ?5% full of scale full scale on lo4 on to 3 1010 ohm ranges, x 10~' to 1013 using largest ohm ranges. available MULTIPLIER & & AMPLIFIER: GAIN: 0.1, 0.3, etc., to 100. FREQUENCY RESPONSE (Within 3 db): dc to 100 cps at a gain of 100, rising to 1.5 kc at a gain of 0.1. NOISE: Less than 3% peak-to-peak of full scale. be INPUT selected IMPEDANCE: in Greater than 1014 ohms shunted by 30 picofarads. decade steps from 1 ohm to 1011 ohms. Input resistance may OUTPUT: ity +-1 volt for full-scale is opposite input polarity. input. Internal resistance is 17 kilohms. Output polar- GENERAL: Output POLARITY: polarity METER is Switch not selects reversed. left-zero (positive or negative) or center-zero scales. CONNECTORS: Input: uhf type; ground binding post. output: Amphenol 80-PC~F. 0565R 2-1 SPECIFICATIONS MODEL 600A ELECTROMETER BATTERIES: Two 413 (30 volts), four El46 (8.4 volts), two RM42R (1.34 volts). 500 hours minimum battery life. DIMBNSIONS, WEIGHT: 10-l/4 inches high x 6-l/2 inches wide x 6-l/2 inches deep; net weight, ?-l/2 pounds. ACCESSORIES SUPPLIED: Mating input and output connectors; binding post adapter, 2-2 0565R O.PEFWION MODEL600AEIJX!TROMETER SEc!PION III - OPEMTION A. comIs Am -m An Controls nector above accessory the is and furnished,. input binding Terminals: connector. post A ground The which input binding plugs connector into post the is is mounted center a UHF of type on the the receptacle. con- panel Front Panel iontrols: RANGE the the ciprocal innut meter. AMPERES resistance switch, of This position, the located designated as control well a in shunt as selects the range to center resistor measure VOLTS, may of bs whose the current. used OHMS, front value to or decrease AMF'ERES. panel is the under the re- On MULTIPLBR RANGE this directly of full the knob scale is dc under set amplifier, multiplied meter switch, on the VOLTS.? reading. meter, located by and the On sets determines OHMS in OHMS the the or or voltage center AMPERES, AMPERES the voltage of range the the setting when setting front sensitivity gives the panel of the ZERO set the control, meter located to sero. at the left under the meter, is used to METER-BATTERY tion, instrument and tests on, switch, determines the batteries. at the meter right polarity under is ZERO input shorted. CBECK terminal switch, through located one megohm, at the bottom while Rear Panel Controls: OUTPUT connector for external recorders. the or zero meter, center turns opera- the right, the amplifier shorts the input when NORMAL-FAST. around FAST position, the the INPUT shunt This GUARD current resistor. control terminal measurements is On locked is OBMS, used. are the in made NORMAL FAST with position position. feedback is In used when impedance sample. INPUT it GUARD. is end desired With of the NORMAL - FAST switch the to test measure sample the is resistance returned on FAST, the low to of a this guarded terminal trol COARSE COARSE in ZERO ZERO. range. switch If the is amplifier used to bring is quite the badly front unbalanced, panel ZERO con- the may ZERO be CENTER brought When within meter range cannot with be this centered control. with ZERO control it og6m 3-l OPERATION B. C. D. PREPARING THE INSTRUMENT FOR OPERATION (1) Set controls as follows: MULTIPLIER: 10 RANGE SWITCH: VOLTS ZERO CHECK WITCH: Locked INPUT TERMINAL: Shield with cap to (2) eero Turn in the approximately bigTER switch 5 to seconds. meter +. The instrument should come with adjusting panel (3) Rotate the to bring front ZERO the panel as the MULTIPLIER required. instrument ZERO control, switch If within it toward use is range impossible COARSE the of high the ZERO to sensitivity ZERO control eero control. the on meter end, rear be involved, shielded (II) used. Connect enclosure. the leads input as should The required various be shielded for accessories measurement. using a for coaxial the If high Model connection impedance 600A may or is used. If short, the the impedance,is binding post low@elow adapter about furnished lOlo ohms) with and the leads instrument can be may kept be measurements. The Keithley Model 6101A Shielded Test Lead will suffice for mDst b@XURING VOLTACE Place If sensitivity the RANGE sensitivity and switch check at of the VOLTS. meter instrument zero. Turn Release MLTIPLIW. is increased, ZERO switch check, recheck to and expected read. the zero reading. MKXXlRING CURRENT (1) NORMAL method (3 amperes to lo-l3 amperes full scale) rear to and Turn the setting the RANGE then RANGE of input, of the read switch the switch instrument the MULTIPLIER Full and unknown to scale MULTIPLIEJt. desired is on sensitivity current.~ switch. AMPERES the NORMAL Check The range. is position. full aero the with Make product scale sure the voltage Connect of ZERO the the CHECK current drop switch settings is switch at the source of the 3-2 0962R MODEL 6COA EIJXlTROMETER OPERA!CION (2) FAST method (low7 to lo-l3 amperes full scale). Proceed as above except with the FAST-NORMAL switch at FAST. The inout drop is now negligible and the inout circuit time constant is reduced at least 100 times. Observe the following cautions: (a) Use only the ZERO CHECK switch to check zero. Do not short the input. (b) The low side of the output is no longer at ground. Therefore, a recorder attached to the output must not be grounded to the Model 6COA. (c) Do not use this method for the measurement of capacitor leakage. E. ----- MEASURING OHMS (1) NORMAL method (10K to lo11 ohms full scale). Turn RANGE switch to desired OHNS range. Make sure that NORMAL-FAST switch is in the NORMAL position. Connect resistance sample to be measured only after ZERO CHECK switch has been locked. The test voltage at full scale is the setting of the MULTIPLIER switch. Before reading OHMS, turn RANGE switch to the ap- proximate range of the unknown resistance. By manipulating the NULTI- PLIER and the RANGE switch, the sample can be tested at a number of test potentials, if desired. This two terminal method is the simplest-and will wcrk quite satis.fac- torily up to about 1011 ohms. At resistances greater than 1011 ohms, it is desirable to employ a GUARD connection both to speed up the re- sponse of the instrument and to nullify the error of leakage across the electrometer input insulation. (2) GUARDED method (10" to lo13 ohms full scale). Proceed as with the two terminal method with the exception that the sample is connected between the INPUT terminal and the GUARD terminal on the rear panel. The FAST-NORMAL'switch must be set at FAST. (3) EXTERNAL VOLTAGE method, Any external voltage may be used. The unknowo is connected between the test potential and the INPUT terminal of the electrometer. The current is then measured, using the NORMAL or FAST method, and the resistance calculated. og62R 3-3 MODEL ~OOAELEC!J!ROME!~ER Proceed as follows: (a) Lock the ZERO CHECK Switch. (b) Connect unknown between INPUT terminal and source of po- tential. A switch should be connected in the hiph voltage line so that when the sample is disconnected from the potential, the low impedance end of the sample is grounded. (c) FAST-NORMAL switch should be at NORMAL. (d) Apply potential to sample before unlocking ZERO CHECK. Start the RANGE switch at low current sensitivities and advance the sensitivity until a reading is obtained. If the potential applied is at least 100 times the ammeter drop (the setting of the MULTIPLIER switch), the resistance is equal to: POTENTIAL APPLUD CURRENT READING If the potential applied is not large compared to the ammeter drop, the resistance is equal to: POTENTIAL APPLIED - INPUT DROP (VOLTS) CURRENT READING le) If it is possible to operate on FAST micro-microanmreter.. the input drop need not be considered in the calculation. F. BATTERY CHECK Turn METER-BATTERY switch to Bl, B2, etc. All batteries should read half scale or higher on the meter. Bl, B3, Bh, and B5 are tested directly. B2a and B2b are tested in series on position B2. Since the battery drains are nearly iden- tical in B2a and B2b, both should be changed when the series arrange- ment reads low. B6 and B7 are not tested because they are operated under virtually shelf-life conditions. They may be replaced yearly as preventive maintenance or may be tested at any time by removing the case and measuring with a voltmeter. They should be replaced if.they test less than eight volts. 3-4 OPERA!l!ION G. USING EXTKRNAL INDICATORS recorders and The pen output drive as of well the amplifiers. as Model hish 6CGA impedance may be used devices to drive such as servo oscilloscopes rebalance (1) For use with servo rebalance recorders; which meter across The the for the 168 terminals. 878 .panel full output ohm ohms output 60 reading the resistor microamperes scale should meter, voltage circuit output If of deflection. a be full the should Shorting terminals used. for consists Model flow scale full be the for 6OOA, connected lower Thus, of scale of a full output but 16.67K be the if 50 millivolts scale 10 low across it terminal does millivolts, resistor is impedances deflection not desired the is.required, voltage affect output through that a placed of the on the (2) any output For range. use is with minus oscilloscopes one volt for and full pen scale recorder meter amplifiers, deflection The volt amolitude mately . frequency range 2 volts which rising response peak can to be to 1 peak. kc delivered is dc on to the 100 bv 10 " volt the cycles amplifier range. on the The 10 is milli- maximum approxi- H. MISCELLANEOUS APPLICATIONS currents when as and currents, ally fier at CURRENT FAST The an the Model mass with position. an the integrator rear operational INTEGRATOR: FAST-NORMAL such spectrometer 6OOA electrometer since is as may placed it for cyclotron be is ampli- switch small used beam basic- in input the tor is Then The of set the has full if at capacitor been Fig. scale VOLTS 600-l replaced charge so value that is by consulted, on chosen there the a capacitor capacitor is (in no it farads) resistance can and in be the and coulombs seen 600A To nect the of the input. placed that integrate suitable GUARD is setting a is polystyrene the now across The simply terminal an standard RANGE value of current, integrator. the,capacity. the the between switch and MULTIPLIER product capacitor resis- con- the Cg62R 3-5 switch (in volts). If it is desired that a time ccnstant be introduced into the integrating circuit the appropriate shunt resistor may be selected by the function switch. Practically, it is suggested that the capacitor be enclosed in a ground- ed can. The connection to the GUARD terminal may be made by a simple un- shielded lead. The connection to the input terminal should be made by means of a coaxial connection to one side of a Wee" adapter. The cur- rent input is made to.the other side of the %eeu. The following procedure is suggested: Depress the ZERO CHECK switch, thus removing the charge from the capacitor and shorting the input. Zero if necessary. Release the ZERO CHECK switch. If the integration is to take place over a long period of time it is suggested that the instrument be used cx the one volt range or higher so that zero drift and grid current will not be factors. CURRENT SOURCE: When measuring ohms, the instrument is designed to supply a constant current to any device placed across its input terminals. The magnitude of the current is equal to the reciprocal of the designation on the OHMS segment of the RANGE switch. Therefore the instrument may be used as a current source for calibration of other instruments if desired. Depress ZERO CHECK and turn RANGE switch to OHMS. The current that is supplied on each range is the reciprocal,of the OHMS setting, and is not affected by the setting of the MULTIPLIER switch. However, for the cur- ,rent to be accurate, the amplifier should be in balance. It will be sufficient to balance the amplifier on the .l volt range of the MJLTI- PLIER Switch. STATIC CHARGE MEASUREMKNTS: The instrument is zeroed and the RANGE switch ulaced on VOLTS. The voltage sensitivity is perhaps placed at 3 or lO*volts full scale. The charged object is then brought near the uncovered, unshielded input connector of the 600A. Depending on the dis- tance between the charge and the instrument a voltage will be induced on the input terminal and can be read on the panel meter. The instrument zero should be checked frequently since accumulation of charge due to the electrometer tube grid current will cause a slow drift of input voltage. Connecting a capacitor across the input reduces the drift due to grid current and also the sensitivity to charge. An electrode connected to the INPUT terminal which increases the capacitance between the INPUT terminal and the charged object will increase the sensitivity to charges. I. ZERO CENTER OPKRATION In some applications, such as null indication or in measuring volt- ages of either polarity near zero, it may be desirable to use the ZERO CENTER position on the bWl'ER-BATTERY switch. Onthis position, opera- tion is just the same as for left-zero (normal), except that for zero input voltage or current, the meter pointer is at center scale. The ZERO CENTER control On the rear panel is used to set the meter pointer to zero for zero center operation. It should require only infrequent attention. 3-6 0962R MODEL 6008 ELECTRCME!I!EB SECTION IV - CIRCFIT DISCUSSION CIRXJlT DISCUSSION Amperes will put voltmeter The The basic impedance various be and discussed with element ohms connections greater a are full following of the measured than scale necessary Model 10 the se 1C by 6OOA sitivity ohms detailed the for is use shunted ampere a of highly of description 10 resistance by and millivolts accurate, 30 ohms micro-microfarads. of measurements standards. the and stable amplifier. an in- dc A. VOLTMETER Refer to DR1201hC at the rear of the manual. FIOURE BOO- 2 which VL 600-2 at potential neutral of is atically. follower. The signal. grounded cathode is sists the attached is driven the amplifier a drives of shows amplifier same follower. cathode or Vl, In to by as ground The other to this instantaneous the V2, the the the proper amplifier the follower chassis amplifier and diagram- is cathode input words terminal output Fig. not V3. con- the out A sequently dividers, fier. reduced Input dividers Accessory input preserving the Model resistance are probes neither 600A the are will high and stable available accuracy. accept input nor impedance 10 accurate for volts extending without and at high accuracy the the impedance. voltage use of the of range input ampli- Con- at Since and to reference to input amplifier cathode minus the ground will amplifier 30 follower while volt ground be batteries made the proper which ground battery to the is as is for "floating". amplifier driven "output supplies the cathode by ground". the for ground In cathode follower the subsequent as amplifier "floating follower, are discussion, referred are ground" the referred plus to and The resistor, the front rear The grid ground. amplifier filaments 'tdummy" panel). of panel) Vl, This bypassed the tube, and are variable input active Rll, operated is for consists returned ~28, high electrometer supply R29;R30, in frequencies of through parallel is two made balanced tube, R31, a up from by variable from R32 is C2. battery 5886 protected B2a, on The voltage SW-& electrometer B2b, Bl. control (COARSE by R15 The to R2, floating grid (ZERO control a ZERO tubes. 109 cf on on 712, ohm the og62R 4-1 CIRCUDl! DISCUSSION M3DEL 6OOAELBXF0ME!!PE2 The electrometer ZERO ccntrcls tube function grid. by adjusting the dc voltage of the dummy through The series voltmeter with Rh2 the develops sensitivity meter, the R33 constant is through determined one R39. volt by Meter the output resistor current for any passing placed ranse. in C3 and R6 serve to stabilize the feedback loop against oscillation. B. AMMETER OUTPUT CHASSIS GROUND Y minimum be will Grid electrometer measured. balanced amperes. ranges, grid trol final less current be or current reading. current than apuarent subtracted the out On The grid will with of tube 2 low Model x the that lo- current and current us~&lly fixes ZERO from input may 600A may con- the the be be PIQURE’ 600- 3 (1) Shunt Resistor Method (NORMAL) measured measured by the from In scale the the voltage one meter normal MULTIPLW by by ohm placing drop. this deflection. to operating 1011 method switch; Currents a ohms resistor connection since in the from decade the setting across 3 range as amperes steps. shown the is switch the input to in The input lo-13 Fig. selects voltage terminals voltage 600-3, amperes resistors drop and current drop may is measuring be selected for ranging is full- (2) Feedback Method (FAST) the feedback impedance In in side the Fig. cathode of voltmeter the 600-1, is side follower applied input; the of discussion the amplifier the through and input cathode output above, conne&or. the ground follower ground shunt floating is resistor. has connected In ground been the ground FAST floats, connected to has connection, the been and low to negative driven impedance the shown low by of from the In the 0.1 FAST NORMAL-FAST Model microamperes position. 6OOA, switch it or The is less. at advantages possible the To bottom change to of use this of the this the connection connection, rear connection panel are: remove and with change currents the lock it to is, shunt (a) the The resistor time effect constant used of input will of the be capacity decreased input is and largely at cable least neutralized, capacity 100 times and as that the 4-2 0962R MODEL6GOAEUXXF0~ CIRCUIT DISCUSSION compared to the NORMAL connection, correspcnding to a loo-fold increase in response speed. (b) The input drop will be reduced~ about 100 times. If Fig. 600-l is again consulted, it will be seen that this connecticn converts the 600A into an operational amplifier with a resistor from the output to the input. Therefore, the following cautions apply: (a) The input cannot be shorted since this will remove the feed- back. (b) The internal impedance of the current source being measured should not be less than about one-tenth of the value of the feed- back resistor used for measurement. (c) This connection should not be used for measuring the leakage current of capacitors since the connection of the capacitor to the input causes the circuit to be transformed into a differentiator with the resultant extreme sensitivity to very small voltage tran- sients. For this measurement the NORMAL should be used. (d) Do not attempt to use the FAST connection for currents exceed- ing 0.1 microamperes. C. OHMMETER (1) Two Terminal Xethod The Model:600A employs a linear scale to provide a megohmmeter of high accur- acy. The linear ohms scale is achieved by supplying a constant current to the sample and measuring the voltage drop across it. The method is shown in Fig. 600-h. CIOURE 600-4 (2) Ohms measurement using GUARD terminal: There are two disadvantages with the method just out- lined: (a) When measuring resistanoes greater than 1011 ohms, input capa- city causes the meter reading to be annoyingly slow. (b) If it is desired to use large voltages across the sample, this same voltage will appear across the input insulation of the electro- meter and the input insulation will contribute error to the reading because of the current also flowing in it. Og62R 4-3 CIRCUl!C DISCUSSION MODEL 6OOAEIBXFiOMgTER For these reasons a second connection for measuring ohms is provided. RX FIQURE 600-8 across slowing the effect input of terminal instrument is input small, capacity. the leakage Also, The from Now, amperes method, the the connected thode-follower that terminal. shows ground input floating. through sistance error resistance switch instrument N0FW.L as feedback since the ground is is with with the the to arrangement. attached reduced. to at Fig. The the amplifier unknown to reduce measuring and the the the is potential is FAST ground result sample 600-5 . GUARD FAST the applied rear moved to the and re- ca- the is is is of (3) Use of External Voltage Supply t With method the of constant measuring current resist- EXTERNAL VOLTAQE t FIQURE 600-6 with ante, unknown rarily time exponential leakage charging since of an the constant-current selected, may measuring RC tends is voltage circuit. not slower charge to be be and across capacitor arbit- long, the the than available the be Due measure on ternal operation). the desirable to AHPERES voltage these the leakage to facts, supply scale use an it current (NORMAL and may ex- and voltage age) applied The current (so unknown the that the measured. voltage, source is the resistance large is voltage connected of compared the voltage. If is across resistance the simply between voltage to the This the equal equals sample voltage the is drop to shosn input the the is is drop an in substantially voltage voltage terminal Fig. appreciable across 600-6. applied applied of the the the electrometer fraction If minus electrometer divided applied the applied the of by volt- the input the 4-4 0962R MODEL 6oOA ELXC!CBOMEZER CIRCUIT DISCUSSION drop divided by the current measured. It will be rarely necessary to correct for the input drop of the electrometer due to the excel- lent voltaRe sensitivity of the Model 600~. It is advisable to use the NOW micro-microammeter connection for the measurement of leakage resistance of capacitors in this manner, since instability is likely to occur using the FAST con- nection. However, in cases where the capacity shunted across the sample is small, it will be possible to realize a considerable increase in speed of response by utilizing the FAST connection. Some precautions are recommended when testing capacitors. Be sure that capacitors have discharged before removing from test circuit. With the ZERO CHECK switch depressed,the input is shorted to ground through 1 megohm, providing a discharge path for the cana- citor. The reading: time may be shortened if the capacitor is al- lowed to charge through a low impedance position on the AMPERES switch before the appropriate measuring resistor is inserted in the circuit. It should be further noted that capacitor measurement is likely to be a slow process in any case due to the fact that it may take considerable time for the molecular orientation of the dielectric to take place at the testing potential. It may take minutes or even hours in some cases to achieve a stable reading. 4-5 AccEssoRm MODEL 600~ ELET'ROEEim SECTION V - ACCESSORIES MODEL 6lOl.A Sl-IIEZOEIC TEZ LEAlk The Model 6101A Lead consists of an input connector, 3 feet of low noise cable and a shielded probe head. Its purpose is to allow convenient connection to the electrometer input. MODEL 61OZA - 1O:l VOLWGE-DIVIDER PIiOBE: The Model 6102A divider probe is intended for general purpose measurements where an extension of the upper voltage range of the 600A is desired. The division ratio is 1O:l correct to 1% and the probe input resistance is lOlo ohms. The probe is supplied with a mating connector and 3 feet of cable. MODEL 6103A Y 1ooO:1VOL!IWE-DIVIDEB PFiOBE: The Model 6103A probe is intended for very high voltage measure- ments at high impedance. The division rat& is 1OOO:l correct to 3% and the probe input resistance is 10 ohms. The probe is supplied with a mating connector and 3 feet of cable. MODEL 61OL TEST SHIELD: The Model 61Oh Test Shield is intended for use in making measure- ments wherein complete shielding of the component under test is required. External terminals are provided for either grounded tests, or a test requiring an external voltage source. 5-l


No as these periodic provided checks maintenance for is by outlined the front is in required Section panel control. other III-E. than The checking method the of performing batteries and The tal accurate calibration chassis should voltage not carrying require of source the Bl, voltmeter adjustment. should B3 Bh be and is used. B5. If set recalibration by This R41 is located set at is on the performed, the factory horison- an A. Trouble Shooting The section circuit will is facilitate completely any described trouble in shooting. Section IV. Study of that age meter moved and at of procedure: The cover If fault the this most range, lifting pointer to by instrument does usual make unscrewing gain with the not access to sure trouble the cover work zero. will that the input to upward. it encountered not However resetting three all will shorted, oring circuitry. be screws With before the necessary the is it the instrument on COARSE that is assuming both The cover not on to instrument possible sides ZERO remove removed, the that back most control of the into the the to cover follow sensitive bring instrument instrument at balance. instrument the is this the re- rear volt- is back. ends the Short tion scale. the'correct satisfactorily zero of the floating This However, the instrument control, is FAST-NORMAL operating most ground is t&indication the that will conveniently point meter to it switch become output is will as possible on that indiczited very ground accomplished be the very the sensitive rear to to circuit difficult on swing remove panel. the by and, the voltage-resistance is the shorting voltage In to operating in negative this hold operating the through condi- on two feed- diagram. Now operating with the points MULTIPLIER of the tube switch electrodes. at .Ol volts, proceed to check the will Regardless value the possible assumed easy or the check cathode, point values depend to marked the that find to is components. on of and on swing found on the the the the the the screen fault. stage the condition circuit where settine diagram. voltage potentials is the First working. diagram. of of voltage At the through the check this ZERO should amplifier Proceed The the cannot point the control, plate be tube correct reasonably be in it balance, and involved this will swung However value grid manner be through the potentials relatively and close it if filament may until then it to the be is og6m 6-1 .MAINlXNANCE MODEL 6OOA ELEC!TRom Miscellaneous troubles: -- Trouble Excessive current erid Excessive drift Excessive phonics micro- Tnstrument not zero. does Cause Defective tube electrometer Battery failing Defective tube electrcmeter See section above Remedy ----- Replace with matched Vl and set V2 Replace batterv Reulace with matched Vl and set V2 See section above where age-resistance The proper the leads method diagram. emerge, of inserting electrometer tubes is with When the inserting fingers. do not touch shown in the volt- the glass base, 6-2 0962R MODEL 600A ELECTROMETER REPLACEABLE PARTS SECTION 7. REPLACEABLE PARTS 7-1. REPLACEABLE PARTS LIST. The Replaceable Parts List describes the components of the Model 600A. The List gives the circuit designation, the part description, a suggested manufacturer, the manufacturer's part number and the Keithley Part Number. The name and address of the manufacturers listed in the "Mfg. Code" column are contained in Table 2. 7-2. HOW TO ORDER PARTS. and Part a. those Number, For parts parts the orders, coded circuit for include designation Keithley the manufacture instrument's and model a description (80164) and must of the serial be part. ordered number, All from structural the Keithley Keithley parts Instruments, describe the Inc. part, In its ordering function a and part its not location. listed in the Replaceable Parts List, completely Keithley b. Order parts through your nearest Keithley Instruments, Inc. distributor or the Sales Service Department, amp CbVar CerD Comp DCb ampere Carbon Variable Ceramic, Composition Disc Deposited Carbon Mil No. Military Type Number n ohm P pica (lo-12) v micro (10-6) f farad v volt k kilo (103) Var Variable w watt M m or meg mega (106) or megohms milli (10-3) ww WWVar Wirewound Wirewound Variable Mfg. Manufacturer TABLE 1. Abbreviations and Symbols. 1164R 7-l REPLACEABLE PARTS MODEL 600A ELECTROMETER @DEL 600A REPLACEABLE PARTS LIST (Refer to Schematic Diagram DR12014C for circuit designations.) BATTERIES Circuit Desig. Bl B2a B2b B4 B3 B5 B6 B7 Mfg. Part No. Keithley Part No. RM42R E146X BA-10 BA-9 E146X BA-9 FM42R BA-10 413 BA-5 413 BA-5 EL46X BA-9 EL46X BA-9 Circuit Desig. Value Rating Type Mfg. Code Mfg. Part No. Description Mfg. Code 8.4 1.34 v v mercury mercury 0.4 v mercury Keithley Part No. Cl02 Cl01 100 100 pf pf Cl03 Cl04 0.02 0.02 uf uf 37942 61637 61637 30 1.34 v v dry mercury cell 37942 61637 30 v dry cell 61637 8.4 v mercury 61637 0.4 v mercury 61637 CAPACITORS 1000 1000 " " CerD CerD 72982 72982 831XSRlOlK 831XSRlOLK c22-LOOP c22-LOOP 1000 " CerD 1000 " CerD 72982 72982 84125V203P 84125V203P C22-.02M C22-.02M MISCELLANEOUS PARTS Circuit Desig. Description Mfg. Code Keithley Part No. JlOL Receptacle, uhf, Input, Mil. No. SO-239A (Mfg. --- No. 6804) Dust No. Cap 7901) for 5101, n, Mil. No. MX-913/U (Mfg. 91737 CS-64 91737 CAP-4 Plug, No. 83-822) uhf, Mate for Input, Mil. No. 49190 (Mfg. Reducing Adapter, uhf, for CS-64 and CS-49, Mil. 02660 cs-49 No. UG-175/U (Mfg. No. 83-185) 02660 CS-36 5102 Binding Post, Black, G (Mfg. No. DF2LBC) 58474 BP-11B 5103 -_- Receptacle, Microphone, Output (Mfg. No. 80-PC2F) Plug, Microphone, Mate for Output (Mfg. No. 80-MC%) 02660 02660 CS-32 cs-33 5104 Binding Post, Red, INPUT GUARD (Mfg. No. DF21RC) 58474 BP-11R Ml01 Meter 80164 ME-16 --- SlOl --- Rotary Switch less components, Range Rotary Switch with components, Range Knob Assembly, Range Switch 80164 SW-63 80164 L2326B 80164 153678 7-2 0765R MODEL 600A ELECTROMETER REPLACEABLE PARTS MISCELLANEOUS PARTS (Cont'd) Circuit Desig. s102 s103 s104 --- SLOS --- --- --- S106 --- --- Mfg. Keithley Code Part No. 80164 14376A 79727 SW-45 80164 SW-51 80164 12094B 80164 SW-47 80164 12093B 80164 L5384A 80164 SW-62 80164 12092B 80164 148388 80164 15110A Circuit Desig. Value Rating Type Mfg. Code Mfg. Part No. Keithley Part No. RlOl R102 R103 18-l LO9 R Not Used lO%, l/2 w 20%, l/2 w R104 RL05 Not Used LO Ml l%, 1 w RL06 R108 R109 RllO R107 a33 !ul Not 312 220 10 m kn Used kG lO%, l%, 1 l/2 w w L%, l/2 w l%, l/2 w RLll R112 Rl13 RL14 Rll5 450 kG l%, L/2 w 3.4 kG l%, 1 w 9 'm lkn 10 kG l%, l/2 w l%, L/2 w 3%, 5 w R116 R117 R119 R118 R120 ;,":i 109 100 n m n n 10 N-l 1% 1% 1% l%, l%, 2 1 w w R121 R122 R123 1M LOO kQ 10 kn l%, l/2 w l%, l/2 w l%, l/2 w * Nominal value, factory set. 0765R Description Push Button, ZERO CEFXK Slide Switch, NORMAL-FAST (Mfg. No. G326) Rotary Switch less components, COARSE ZERO Rotary Switch with components, Coarse Zero Rotary Switch less components, MULTIPLIER Rotary Switch with components, Multiplier Knob Assembly, Multiplier Switch Rotary Switch Less components, METER-BATTERY Rotary Switch with components, Meter-Battery Knob Assembly, Meter-Battery Switch Knob Assembly, ZERO Control RESISTORS Comp Comp DCb Comp DCb DCb 01121 EB 75042 BTS 91637 DC-1 Rl-1M R37-109 R13-10M 01121 EB 91637 79727 DC-1 CFE-15 Rl-33K R13-10M R12-312K DCb 79727 CFE-15 R12-220K DCb 79727 CFE-15 R12-450K DCb 91637 DC-l R13-3.4K DCI, DCb 79727 CFE-15 79727 CFE-15 R12-9K R12-LK WWVar 73138 A RP4-10K DCb DCb 63060 Rx-1 63060 Rx-1 DCb DCb DCb 63060 91637 91637 R20-loll R20-1010 R20-10g R14-100M R13-10M DCb R12-LM DCb R12-100K DCb R12-10K 7-3 Rx-1 DC-2 DC-1 79727 CFE-15 79727 CFE-15 79727 CFE-15 REPLACEABLE PARTS MODEL 600A ELECTROMETER RESISTORS (Cont'd) Circuit Desig. Value Rating 'We Mfg. Code Mfg. Part No. Keithley Part No. R124 R125 100 1 kn n R126 R127 R128 (1) 10 R *20 ln n 450 kc? RL29 8.6 kn R130 8.6 kn R131 8.6 krl R133 R132 8.6 166.7 ko k~ R134 50 kn R135 16.7 k~ R136 RL37 5 1.667 kn k~ RL38 500 n RL39 166.7 n R140 (2) *lo 9kn ksl R141 RL42 16.67 10 kn kn R144 R143 47 600 kcl ko R145 47 ko R146 1.14 m R147 Not Used R148 250 kn R149 R150 900 1.14 k.0 & Circuit Desig. l%, l/2 w l%, LO w ww 79727 CFE-15 91637 RSE-10 R12-LK R34-100 l%, 10 w l%, .l%, 10 2 w w ww ww ww 91637 RSE-LO 01686 91637 RSE-10 7070 R34-10 R34-1 R92-20 L%, l/2 w DCb 79727 CFE-15 RL2-450K L%, l%, L/2 l/2 w w DCb DCb 79727 CFE-15 R12-8.6K 79727 CFE-15 R12-8.6K l%, l/2 w DCb l%, l/2 w DCb l%, l/2 w DCb l%, l%, L/2 l/2 w w DCb DCb L%, l/2 w l%, l/2 w DCb DCb l%, L/2 w DCb L%, l%, l/2 l/2 w w DCb DCb L%, l/2 w DCb lO%, 2 w l%, l%, l/2 l/2 w w l%, L/2 w l%, l/2 w l%, l/2 w 20%, L/4 w l%, L/2 w L%, L/2 w 79727 79727 CFE-15 CFE-15 Rl2-8.6K R12-8.6K 79727 CFE-15 79727 79727 CFE-15 CFE-15 RL2-166.7K R12-50K R12-16.7K 79727 CFE-15 79727 CFE-15 79727 CFE-15 79727 CFE-15 79727 CFE-15 79727 CFE-15 71450 79727 79727 79727 79727 79727 71450 79727 79727 RL2-SK ~12-1.667~ R12-500 Rl2-10K Rl2-166.7 RL2-9K WWVar DCb Deb DCb DCb WP RP9-1OK CFE-15 CFE-15 CFE-15 RLZ-47K R12-16.67K R12-600K CFE-15 R12-47K DCb CFE-15 R12-1.14M CbVar DCb DCb RQll-130 RP2-250K CFE-15 R12-900K CFE-15 R12-1.14M VACUDM TUBES Number Mfg. Code Keithley Part No. VlOl v102 5886 5886 80164 80164 EV-5886-2 EV-5886-2 v103 6418 81453 EV-6418 v104 6418 81453 EV-6418 9~ (1) Nominal If used, value, this factory resistor set. is in parallel with R127. (2) If used, this resistor is in parallel with R139. 7-4 0765R MODEL 600A ELECTROMETER REPLACEABLE PARTS

11121 Allen-Bradley Corp. Milwaukee, Wis. 12660 Amphenol-Borg Broadview, Chicago, Electronics Illinois Corp. 37942 Mallory, Indianapolis, P. R., Ind. and Co., Inc. $4655 Ohmite Skokie, Mfg. Ill. Co. 58474 Bristol, Superior Electric Corm. Co., The 61637 Union New York, Carbide N. Y. Corp. 63060 Victoreen Cleveland, Instrument Ohio Co. 71450 CTS Elkhart, Corp. Ind. 72982 Erie Technological Products, Inc. Erie, Pa. 75042 International Philadelphia, Resistance Pa. Co. 79727 Continental-Wirt Electronics Corp. Philadelphia, Pa. 80164 Keithley Instruments, Inc. Cleveland, Ohio 81453 Raytheon Industrial Co. Components Div. Industrial Tube Operation Newton, Mass. 91637 Dale Electronics, Inc. Columbus, Nebr. 91737 Gremar Mfg. Co., Inc. Wakefield, Mass. Manufacturers, TABLE 2. Code List of Suggested Manufacturers. Cataloging Handbook H4-1.) (Based on Federal Supply Code for








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