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Keithley 614 Instruction Manual
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Keithley 614 Instruction Manual

Keithley 614 Instruction Manual

Electrometer
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Model
614
Electrometer
Instruction
Manual
-øta
[6,
zee
•Nite
Contains Operating and Servicing Information
KEITHLEY

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Summary of Contents for Keithley 614

  • Page 1 Model Electrometer Instruction Manual -øta •Nite Contains Operating and Servicing Information KEITHLEY...
  • Page 2 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.
  • Page 3 Model Electrometer Instruction Manual 0 1981, Keithley Instruments, Inc. Test Instrumentation Group All rights reserved. Cleveland, Ohio, U.S.A. July 1991, Fourth Printing Document Number: 31896 Rev. D...
  • Page 4 + ld Model 6011 Input Cable 200gA IOOnA 0.01% + 0.3d ± 200gA Model 6102A Voltage Divider Probe (up to 200V with 614) 0.3% + ld 2000gA Model 6103C Voltage Divider Probe (up to 20kV with 614) •With current suppress.
  • Page 5 (IEC) Standard IEC 664, digital multimeter measuring circuits Ihe types of product users are: (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) are Installation Category II. All other instruments' signal terminals are Responsible body is the individual or group responsible for the use Installation Category I and must not be connected to mains.
  • Page 6 NOT as safety earth ground connections. leads, and input jacks, must be purchased from Keithley Instru- ments. Standard fuses, with applicable national safety approvals, If you are using a test fixture, keep the lid closed while power is ap- may be used if the rating and type are the same.
  • Page 7 TABLE OF CONTENTS Paragraph Title Page SECTION I-GENERAL INFORMATION Introduction ..Features Warranty Information . Manual Addenda Safety Symbols and Terms Unpacking and Inspection . Specifications SECTION 2 - OPERATION Introduction ..........Preparation for Use .. 2.2.1 Battery Power 2.2.2...
  • Page 8 TABLE OF CONTENTS (continued) Title Paragraph Page SECTION 4 - PERFORMANCE VERIFICATION Introduction... Environmental Conditions ... Recommended Test Equipment Performance Verification Procedure Initial Conditions Volts Verification Current Verification Input Current Verification Resistance Verification... 4.10 Charge (nC) Verification SECTION 5 - THEORY OF OPERATION Introduction..
  • Page 9 Power Supply PC-596, Component Location Drawing Dwg. No. 31886 Display Board PC-597, Component Location Drawing Dwg. No. 31881 7-11 Model 614 Electrometer PC-596, Schematic Diagram Dwg. No. 31895.. 7-13 Power Supply PC-596, Schematic Diagram Dwg. No. 31895 7-15 Display Board PC-597 Schematic Diagram, Dwg.
  • Page 10 Ohms Range for Test Current . Performance Verification Equipment DC Volts Verification.. Resistance Verification. Feedback Resistors Feedback Elements Model 614 Ranging Circuit . Performance Verification Equipment Offset Jumper Setup Model 614 Static Sensitive Device Power Supply Checks..Preamplifier Circuitry Checks...
  • Page 11 4. Decimal point positioned by range push button. • Battery pack standard. Complete portability. Full charge • A Model 614 Electrometer is maintained when the Model 614 is plugged in. Bat- • A Model 614 Instruction Manual teries at full charge will provide 10 hours of operation.
  • Page 12 ELECTROMETER Iqooo CURRENT INPUT SUPPRESS FUNCTION RANGE UNITS SOOV ZERO CHECK ZERO 'SOV 3sov 's v 'sov Model 614 Front Panel Figure I-I. PREAMP soov WARNING:Æ mTA.N CHASSIS COMMON WITHIN EARTH. OISCONNECT L me CORO BEFORE FUSE ANALOG OuTPuT SLOwBL...
  • Page 13 Model 614 from line C. Select Range (20). power. As long as the Model 614 is operating on line power, 8. CURRENT SUPPRESS ON/OFF—Depressingthis the battery pack is charged or maintained at full charge. The push button turns on the Current Suppress circuit.
  • Page 14 Select the Volts function and the .2V range. NOTE The Model 614 should display .00000 ± 1 digit. If the Current Suppress is active only when display is not .00000 1 digit, adjust the VOLTS ZERO Current function (l) is selected.
  • Page 15 FUSE— The fuse is rated at 1/8A, 3AG, 250V. LINE VOLTAGE Switch—The LINE VOLTAGE switch CABLE selects eithe90V - 125V or 180V - 250V operation (see paragraph 2.2.2). Chassis Ground Terminal— This terminal provides a connection to chassis ground (outside shell of input con- —...
  • Page 16 In this metals are at different temperatures. Low thermal connec- case, the Model 614 can be isolated from the power line by 'tions are used to minimize thermal EMFs. Crimped or cad- utilizing battery power.
  • Page 17 Make current measurement as follows: 7 . Take the reading. The reading is in kQ, or GQ 1. Turn the Model 614 on and allow one hour warm up. depending on the Units selected. 2. Depress ZERO CHECK. Select Current Function.
  • Page 18 (R or C) from Preamp Out (rear panel) to the Model 614 input using the recommended shielded test box. 1. Turn the Model 614 on and allow one hour warm up. 2. Depress ZERO CHECK. Model 6146 Triax Select Charge function (nC).
  • Page 19 It is necessary to shieldresistances greaterthan 1070if a stable reading is expected. 100M With the constant voltage method, the Model 614 is used as TO rest of the circuit. an ammeter to directly read the leakage current through the unknown resistance.
  • Page 20 100gA less than 0.1% with a 200mV source. High capacitance 10gA diodes (e.g. zeners) present no problem, since the Model 614 is insensitive to stray input capacitance up to O.14F. 100nA 2.6.4 Diode Characterization With the constant current ohms configuration...
  • Page 21 Keithley electrometers and other high im- pedance multimeters. It requires the Model 6012 Coaxial to Triaxial Adapter when used with the Model 614. Lead length is 0.8m (30"). See Figure 3-2. Figure 3-2. Model 6103C Figure 3-3. Model...
  • Page 22 6147 Triax to BNC Connector allows the Model 614 to be used with all Keithley acessories and cables requir- cable 0.9m (three feet long) terminated with alligator clips. This cable mates directly with the Model 614 input. The ing BNC connections.
  • Page 23 VERIFICATION INTRODUCTION INITIAL CONDITIONS The Model 614 must be turned on and allowed one hour for Performance verification may be done upon receipt of the warmup. If the instrument has been subjected to extremes instrument to ensure that no damage or misadjustment...
  • Page 24 DC calibrator (Item A), decade resistor Zero has not been verified (paragraph 4.6). (Item E) and the Model 614 as shown in Figure 4-2. Repeat steps 3 and 4 using 10.00MQ and .01900V. Verify that the reading is between 1871 and 1929.
  • Page 25 (a) Select Current (l), 20nA range and depress ZERO Chassis CHECK. (b) Configure the DC calibrator (Item A) decade resistor (Item E) and the Model 614 as shown in Figure 4-4. (c) Set the DC calibrator to O.IV and set the decade resistor to IOMQ.
  • Page 26 Model 614 must be guarded. See section To confirm Coulombs operation, proceed as follows: 1. Turn the Model 614 on. Depress ZERO CHECK. Set the 2.4.1. DC (Item A) calibrator to 00.000. 2. Connect the 1000pF capacitor,...
  • Page 27 (with 6 x 1014A input current) for the Current to 200GQ with minimal error. To accomplish this, the Model and Coulombs functions. Refer to Figure 5-2 for the basic 614 includes a special preamplifier circuit which gives it the circuit configurations provided for the different functions. electrometer characteristics.
  • Page 28 30gA bias to Q104. If the input FET pair is ever replaced, reinstall jumpers W 101 and W 102 In the Volts function the Model 614 is configured as a high and follow the procedure for nulling the input offset voltage.
  • Page 29 5.4 RESISTANCE Table 5-1. Feedback Resistors The Resistance function operates similar to the Volts func- UNITS tion, except that a reference voltage of IV is generated by SELECTION RELAY UIOI, VRIOI, and associated components. Potentiometer R101 sets this voltage which can be measured between TPI K103 R121, (R108 on 2000) C112 and TP2.
  • Page 30 Capacitors C109, Clll, and Cl 12 provide frequency stabili- involves adjusting R101 and monitoring TPI ty to the feedback circuit. for I.oooov ±500gv. See paragraph 6.4.3 No calibration is necessary for R120 and R121. However, RI 17 is a 9.8 x 1090 HI meg resistor requiring calibration. For the 200kQ range, it IS necessary to switch R108 in series This is provided by RI 14.
  • Page 31 The following table summarizes 1<101 R117, C109 the gains selected. K104 C113 C' 16 RI 28 From Preamp Out Radj IJ104 2V Analog + 6.4V Output Suppress Adj C114 CIIS To A/D -6.4V Figure 5-6. Model 614 Ranging Circuit...
  • Page 32 Table 5-3. Gain Selection During float charge the battery voltage is maintained at 9.5V. As long as AC power is applied to the instrument, the batteries are maintained at this voltage. Current drawn from the regulator during float charge is essentially the current re- RESISTOR ADJUSTMENT GAIN...
  • Page 33 The Model 614 A/D Converter operates on the dual slope The number of clock pulses required for the integrator to principle. The A/D circuitry consists of an integrated circuit return to baseline level is proportional to the input signal.
  • Page 35 Adjust R138 to full counterclockwise and set the supp- ± IOC and a relative humidity of less than 70%. ly voltage to 9V. Turn the Model 614 ON and the supp- ly ON. The Model 614 must be turned on and allowed one hour for Set the supply voltage to 7.4V.
  • Page 36 6.4.2 Volts Calibration Adjust theVOLTSZERO pot on the front panel(R103, Turn ON the power to the Model 614 and depress located directly underneath the input connector) for a ZERO CHECK. display of .00000 ± 1 digit. Connect the DMM (Item B, Table 6-1) to the Model NOTE 614's 2V Analog Output.
  • Page 37 DESIGNATION PART NUMBER Connect the DB-62 (Item E), the DC calibrator (Item 13105 IC-103 A), and the Model 614 as shown in Figure 6-2. 13106 IC-102 13202 LS141 ICII]IJ Devices should be handled and transported in protective containers, antistatic tubes or conductive foam.
  • Page 38 Table 6-4. Power Supply Checks REMARKS REQUIRED CONDITON ITEM/COMPONENT STEP Unit on line power, FIOI removed unless otherwise noted. Output of CR103 14V to Bridge Rectifier Voltage in Step 1 minus .7V CR104, cathode (diode drop) +9.5V ± . IV at full charge U109 output Input of +5V Regulator +8.5V...
  • Page 39 + terminal; black is To replace FIOI do the following: connected — terminal. Unplug the Model 614 and remove the top cover. 4. Connect the power leads (positive lead first) and install Carefullylift out FIOI. Replacewith a fuse of ap- top cover.
  • Page 40 Battery Shield 31893 Battery Pack BA-35 Negative Terminal Positive Terminal FIOI Battery Fuse F102 1/8A, 250V 3AG Figure 6-3. Battery Replacement...
  • Page 41 COVER 30540 BATTERY COVER 31893 SHIELD 32010 SCREENED REAR PANEL BUSHING 31876 32044 BP-11-2 BP-15 Black BINDING POSTS BP-II-O INPUT CONNECTOR CS-440 CONNECTOR HOUSING see Figure 6-5 CS-270 CONNECTOR Knob cs-236 KN-42 CONTACT CS-339-3 OVERLAY BOTTOM COVER 31873 30541 Feet (4 required) TILT BAIL...
  • Page 42 SC-30 CABLE FROM CS-440 SLIDE LU-90 ONTO CS-357 GRN WIRE FROM CS-440 CRIMP LU-9D /7x 3/3"3/8"". INS. BRINK TU8/N6 SHIELD BACK '4" CLEAN WITH FREON STRIP TD 9B" / 7 x 3/32"x 1/2"Lb. SHRINK TUB/N6 NOTE After replacing any components related to the high impedance circuitry...
  • Page 43 See the inside front cover for addresses. When location information for the Display Board . Figure 7-4 is the ordering include the following information: schematic for the Model 614, Figure 7-5 is the schematic for Instrument Model Number...
  • Page 44 Table 7-1. Model 614 Mother Board PC-596 Location Keithley Circuit Description Part Desig. 4 D-Size Lead-Acid Cells BA-35 BTIOI 33p, looov, Cer D C-64-33p CIOI c-305-.01 .01gF, 100V, Mtl Poly C102 .1gF, 16V, Cer D c-238-.1 C103 .1gF, 16V, Cer D c-238-.1...
  • Page 45 Table 7-1. Model 614 Mother Board PC-596 (Cont.) Circuit Location Keithley Desig. Description Part 0106 JFET, N Channel, PF 5301 TG-139 0107 Transistor, PNP, 2N3906 TG-84 0108 Transistor, PNP, Darlington, MPS-U95 TG-133 PNP, Darlington, 0109 Transistor, MPS-U95 TG-133 0110 MOS FET,...
  • Page 46 Table 7-1. Model 614 Mother Board PC-596 (Cont.) Location Kelthely Circuit Part Desig. Description R-88-24.9k R146 24.9k, 1%, 1/8W, MtF 200k, 5%, 1/4W, MtF R-76-200k R147 R-88-3.83k R148 3.83k, 1%, 1/8W, MtF R-76-33k RI 49 33k, 5%, 1/4W, Carb R-76-22M...
  • Page 47 Table 7-2. Model 614 Display Board PC-597 Circuit Location Keithley Desig. Description Part C201 .15gF, 50V, Polyprop c-269-.15 C202 .22gF, 50V, Polyprop c-269-.22 C203 .22gF, 50V, Polyprop c-269-.22 14F, 50V, Polycarb C204 c-215-1 C205 10gF, 25V, Alum c-314-10 CR201 Rectifier...