Keithley 195A Instruction Manual Download

Page: 53 / 138

Summary of Contents for 195A

Page 1: ...Model 195A Digital Multimeter Instruction Manual 105A DIGriAt MULTIMETER OHMS VOLTS SENSE OHMS laiiil AUTO msmsm DOWN PROG PRGM Contains Operating and Servicing Information KEITH LEY...

Page 2: ...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 INDI RECT SPECIAL INCIDENTAL OR CONSEQUENTIAL...

Page 3: ...el 195A Digital Multimeter Instruction Manual 1984 Keithley Instruments Inc Test Instrumentation Group All rights reserved Cleveland Ohio U S A April 1991 Sixth Printing Document Number 195A 901 01 Re...

Page 4: ......

Page 5: ...o of peak to rms Up to 3 1 allowable INPUT IMPEDANCE 2M12 shunted by less than 75pF MAXIMUM ALLOWABLE INPUT 1000V peak IOVHz BENCH READING RATE 3 readings second CMRR Greater than 60dB at DC 50 or 60H...

Page 6: ...peration 5 Calibration Performs digital calibration 6 Temperature Allows C and F temperature measurements 7 Data Logger Allows 100 reading storage at 9 programmable rates also stores highest lowest an...

Page 7: ...85 Clamp On AC Current Probe 1 11 9 Model 1691 General Purpose Test Lead Kit 1 11 10 Model 1950 AC Voltage AC and DC Current Option 1 11 11 Model 1951 Input Adapter Box 1 11 12 Model 7008 IEEE 488 Cab...

Page 8: ...otes 3 5 Program Description 3 5 1 Program 0 Clear 3 5 2 Program 1 Non Volatile Storage 3 5 3 Program 2 Multiplex 3 5 4 Program 3 IEEE Address and Talk Only Mode 3 5 5 Program 4 Line Frequency 3 5 6 P...

Page 9: ...10 8 EDI K 4 10 9 Multiplex A 4 10 10 Delay W 4 10 11 Status Word U 4 10 12 SRQ Mode M and Status Byte Format 4 10 13 Buffer Command Q and B 4 10 14 Data Format G 4 10 15 Digital Calibration D 4 10 16...

Page 10: ...on During Model 1950 Option Measurements 6 8 Temperature Measurement 6 8 1 RTD Resistance Measurement 6 8 2 FET Switching Sequence 6 8 3 Reading Calculations SECTION 7 MAINTENANCE 7 1 Introduction 7 2...

Page 11: ...8 7 Input Multiplexer and Buffer Amplifier 7 8 8 Digital Circuitry 7 8 9 Model 1950 AC Amps Option 7 8 10 Buffer Amplifier Gain Checks 7 10 7 14 7 14 7 17 7 17 7 17 7 17 7 17 SECTION 8 REPLACEABLE PA...

Page 12: ...000 and 2k0 Ranges Connections for Verification of 20k0 Through 20MO Ranges Verification Connections for Current 2 8 2 8 2 10 2 11 2 11 2 12 2 12 2 13 2 14 3 1 4 1 4 2 4 5 4 7 4 7 4 7 4 7 4 8 4 8 4 21...

Page 13: ...tions Calibration Jumper Locations Model 195 Exploded View NVRAM Board Component Location Drawing Dwg No 195 160 Model 1950 AC Option Component Location Drawing Dwg No 1950 150 Mother Board Component...

Page 14: ...RQ Mask Commands 4 17 Status Byte Interpretation 4 18 Buffer Rate Command Parameters 5 1 Recommended Test Equipment for Performance Verification 5 2 Limits for DC Voltage Verification 5 3 Limits for R...

Page 15: ...Checks 7 19 Digital Circuitry Checks 7 20 Model 1950 Option Checks 7 21 Buffer Amplifier Gain Checks 8 1 Index of Model 195 Schematics and Component Layouts 8 2 Mother Board Parts List 8 3 NVRAM Board...

Page 16: ...d in the specifications and operation section SAFETY PRECAUTIONS FOR HIGH ENERGY CIRCUITS To optimize safety when measuring voltage in high energy distribution circuits read and observe the directions...

Page 17: ...mmed 6 Front and Rear Panel Input Terminals Input terminals are duplicated on the front and rear panels to allow easy con nections in both bench and rack mounted situations The selected set of inputs...

Page 18: ...wer source as described below 1 8 1 Line Power The Model 195A is designed to operate from 105 1 25V or 210 250V 50 60HZ AC power sources A special powder transformer may be installed for 90 1 10V and...

Page 19: ...provide a reading of 50mV on the meter 1 11 5 Model 1681 Clip On Test Lead Set The Model 1681 set contains tw o leads 1 2m 48 inches in length Each lead is terminated with a banana plug on one end an...

Page 20: ...s well as other general purpose applica tions The Model 8693 measures between 220 C and 630 C and has a basic tolerance of 0 3 C at 0 C 1 11 15 Model 8695 Surface Probe The Model 8695 probe is designe...

Page 21: ...strument is set for that mode OHMS The OHMS button sets the Model 195A up to measure resistance When this button is depressed the in dicator above the button turns on All the front panel controls exc...

Page 22: ...The RECALL ENT button is used to enter and recall data associated with the front panel pro grams 2 2 2 Terminals The terminals are used to connect the Model 195A to the voltage current resistance or t...

Page 23: ...LINE FUSE This fuse provides protection for the AC power line input 2 AMPS FUSE This fuse protects the Model 1950 option from excessive current CAUTION The AMPS FUSE only protects the instru ment fro...

Page 24: ...ith the factory programmed value of 16 the display will show Tr it lb 6 Following these display messages the instrument will go into the normal operating mode and begin displaying readings The instrum...

Page 25: ...ment from the AC mode 5 To measure AC current with the 1950 option depress the AMPS button If the AC indicator is off depress the AC button as well NOTE The selected function affects the integration p...

Page 26: ...e the zero mode must dis abled and then enabled once again The new value will be stored with the first triggered conversion 5 The zero mode should not be used to null the small offset in the AC mode 6...

Page 27: ...g steps 1 Enter the one shot mode by depressing PRGM and TRIG 9 in sequence The TRIG light will turn on and the decimal point on the display will cease flashing indicating the instrument is in the one...

Page 28: ...ming to the specifications in Figure 2 4 will appear at the VOLTMETER COMPLETE output on the rear panel each time the Model 195A completes a conversion To use the VOLTMETER COMPLETE output proceed as...

Page 29: ...he LO terminals on the Model 195A are designed to float from chassis ground to avoid ground loop problems Chassis ground is connected to power line through the ground wire in the power cord when used...

Page 30: ...rrors caused by the voltage drop across the test leads that occurs when 2 terminal measurements are made To make resistance measurements proceed as follows 1 Turn on the power with the front panel POW...

Page 31: ...eads from the Model 195A before connecting the adapter box or temperature probe 1 Connect the Model 1951 Input Adapter Box to the VOLTS OHMS and OHMS SENSE terminals on the front or rear panel of the...

Page 32: ...perature standard is the IPTS 68 standard which uses different calibration parameters as summarized in Table 2 7 Note that it is im perative that the instrument be calibrated for the standard for whic...

Page 33: ...t exceed 700VRMS 1000V peak be tween the HI and LO terminals or the instru ment might be damaged INPUT IMPEDANCE 2M0 SHUNTED BY LESS THAN 75pF Figure 2 11 AC Voltage Measurement Front Panel Connection...

Page 34: ...Installed will result in a NO OP message on the display 4 Select a range suitable to measure the expected current or use the autorange mode if desired 5 Select appropriate resolution and filter modes...

Page 35: ...his waveform is 5V but the average responding meter will give a reading of 3 53V 3 1 8 x 1 1 1 creating an error of almost 29 4 A similar situation exists for the rectified square wave which has an av...

Page 36: ...er Reading Reading Percent Error K Ti T n DUTY CYCLP 7 07V 7 07V 7 07V Half Wave Rectified Sine 5 00V 3 53V 5 00V 29 4 Full Wave Rectified Sine 7 07V 7 07V 7 07V Square 10 r T lOV lO OOV ll lOV lO OOV...

Page 37: ...arized in Table 3 1 3 2 PROGRAMMING CONTROLS Most of the front panel controls serve a dual purpose The FUCNTION RANGE MODIFIER and TRIG buttons are numbered in sequence Figure 3 1 shows the controls u...

Page 38: ...ROGRAMMING NOTES The Model 195A has a number of display messages associated with program operation General display messages that are used with most or all the programs are listed in Table 3 2 Note tha...

Page 39: ...G Once the desired constant value is shown on the display the constant is entered into the program by pressing ENT 3 5 PROGRAM DESCRIPTIONS The following paragraphs describe the purpose and operation...

Page 40: ...ing steps describe the programming sequence For more com plete information on IEEE 488 operation refer to Section 4 To enter Program 3 perform the following steps 1 Press PRGM The instrument will prom...

Page 41: ...can easily calibrate the Model 195A by applying an accurate calibration signal and using this program The calibration signal can be a prompted value or a number entered from the front panel The steps...

Page 42: ...that value instead of the nominal value for better overall accuracy 13 The unit will now prompt for operation on either the DIN or NBS IPTS 68 standard The importance of this selec tion lies in prope...

Page 43: ...ESOLN button on the front panel controls display resolution When in the 5 2 digit mode the character is replaced by the least significant digit of the temperature reading 2 Temperature measurements ma...

Page 44: ...in the highest reading in the buffer press 1 The instrument will briefly display the following bH This message will be followed by the number of the high reading and the reading itself 16 The instrume...

Page 45: ...owing message will be displayed briefly PPS5 I 6 If the ROM test failed the following message will be displayed I I 7 To program the Model 195A for use with the Model 1950 option press the minus butto...

Page 46: ...le Given a transducer reading of 21212 at 0 PSI and 32 412 at 556 PSI suppose it is desired to scale the reading so that the 21212 resistance will read 012 while the 32 4kl2 resistance reads 55612 Thi...

Page 47: ...oth data and most commands Five bus management lines and three handshake lines round out the complement of signal lines Since the bus is of parallel design all devices connected to the bus have the sa...

Page 48: ...y error messages If the handshake sequence stops for any reason DATA SOUR 4 3 1 Bus Management Lines The bus management group is made up of five signal lines that help ensure an orderly transfer of da...

Page 49: ...t up for remote operation Generally the REN command should be sent before attempting to program instruments over the bus 2 EOl End Or Identify The EOl command is used to positively identify the last b...

Page 50: ...ands The meaning of the device dependent commands is deter mined by instrument configuration Generally these com mands are sent as one or more ASCII characters that tell the device to perform a specif...

Page 51: ...4 4 Typical Device Dependent Command Se quence Step Command ATN State Data Bus ASCII Hex Decimal 1 UNL Set low 3F 63 2 LAG Stays low 0 30 48 3 Data Set high F 46 70 4 Data Stays high 0 30 48 5 Data S...

Page 52: ...PRIMARY 1 PRIMARY 0 PRIMARY 0 PRIMARY...

Page 53: ...CONTROLLER A SIMPLE SYSTEM CONTROLLER Figure 4 4 System Types Figure 4 5 IEEE 488 Connector INSTRUMENT INSTRUMENT INSTRUMENT Figure 4 6 IEEE 488 Connections...

Page 54: ...8 Contact Assignments CAUTION The voltage between IEEE common and ground must not exceed 30V or damage to the instrument may occur Table 4 5 IEEE Contact Designations Contact Number IEEE 488 Designat...

Page 55: ...only mode perform the following steps 1 Press the PRGM and 3 buttons in sequence 2 To enter the talk only with prefix mode press 4 0 and ENT in sequence 3 To cancel the talk only mode enter Program 3...

Page 56: ...o avoid possible conflicts 4 8 3 Interface Function Codes The interface function codes are part of the IEEE 488 1978 standards These codes define an instrument s ability to sup port various interface...

Page 57: ...paragraph 4 10 4 9 GENERAL BUS COMMAND PROGRAMMING General bus commands are those commands which have the same general meaning regardless of instrument configura tion These commands are grouped into...

Page 58: ...lowing statment into the HP 85 ABORTIO 7 END LINE After the END LINE key is pressed the TALK light will turn off indicating the Model 195A is in the talk idle state 4 9 3 LLO Local Lockout The LLO com...

Page 59: ...he SDC command the controller must perform the following steps 1 Set ATN true 2 Address the Model 195A to listen 3 Place the SDC command on the data bus Programming Example Using the front panel contr...

Page 60: ...more numbers designating specific parameters For example a function is programmed by sending an ASCII T followed by numbers representing the function The IEEE bus treats device dependent commands as...

Page 61: ...n 16 reading samples 414 digits averaged S6 100ms integration period 1 reading sample 5 i digits averaged S7 100ms integration period 2 reading samples digits averaged S8 100ms integration period 4 re...

Page 62: ...execute character also controls instrument operation in the T4 and T5 trigger modes as described in paragraph 4 10 7 NOTE Command strings sent without an execute character will not be executed at tha...

Page 63: ...range 4 10 4 Rate S The rate command controls the following Model 195A parameters 1 The integration period 2 The number of readings averaged 3 Usable resolution These parameters are summarized in Tab...

Page 64: ...is triggered Zeroed readings will then be displayed with each subsequent triggered conver sion For example If the Model 195A is placed in one of the one shot trigger modes the first trigger following...

Page 65: ...dicating that one reading has been processed To continue taking readings in this mode one talk command must be sent for each conver sion 4 10 8 EOl K The EOl line on the bus is usually set low by a de...

Page 66: ...lay W status are each two bytes in length The remaining status parameters in the UO status word are each one byte in length 3 To make sure the correct status is returned the status word should be read...

Page 67: ...sending the ASCII letter M followed by a decimal number to set the appropriate bits Table 4 16 lists the commands to set the various mask bits while Figure 4 10 a shows the general mask format Table...

Page 68: ...e computer conducts a serial poll and displays the status byte bits in order on the CRT The SRQ B6 error B5 and IDDCQ BO bits are set because line 40 of the program attempted to program the instrument...

Page 69: ...dicated by the read pointer NOTES 1 Buffer operation can also be controlled from the front panel as described in paragraph 3 5 8 2 The Model 195A can be programmed to generate an SRQ when the buffer i...

Page 70: ...ected S mode 4 Programmed terminator and EOl sequences appear at the end of each reading in the GO G1 and G4 modes but are transmitted only at the end of the buffer in the G2 G3 and G5 modes No termin...

Page 71: ...command a calibration value can be transmitted to the instrument Once the calibration value is stored the MPU can then check the calibration value against the measured signal to maintain in strument...

Page 72: ...e END LINE key is pressed the second time NV storage takes place 4 10 17 Self Test J The J command causes the instrument to perform the same tests it automatically performs upon power up When the self...

Page 73: ...can be displayed are limited by the capabilities of the 7 seg ment readouts but even with those limitations considerable versatility is possible Messages may be controlled with the following commands...

Page 74: ...t panel error messages employed by the Model 195A The messages in Figure 4 13 a results from an Illegal Device Dependent Command IDDC while the message in Figure 4 13 b results from an Illegal Device...

Page 75: ...no remote error message in Figure 4 13 c is displayed on the front panel of the instrument for about one second 4 12 READING RATES The maximum reading rate depends on several factors in cluding selec...

Page 76: ......

Page 77: ...in the readings obtained while performing the verifica tion procedure Some of the equipment listed in Table 5 1 does not have specifications at least four times better than those of the Model 195A be...

Page 78: ...r output to exactly 19 0000mV Verify that the display shows a reading within the limits stated in Table 5 2 5 Change the Model 195A to the 200mV range and change the calibrator output voltage to 190 0...

Page 79: ...2 Switch the instrument to the 2k0 range and check to see that the reading is within pre scribed limits 6 Connect a 19k0 calibration resistor to the instrument as shown in Figure 5 3 Note that the 2 t...

Page 80: ...measurement at 20kHz only 8 Place the INPUTS switch in the rear panel position and repeat the entire procedure using the rear panel VOLTS OHMS terminals 5 5 4 DC Current Accuracy Check With Model 1950...

Page 81: ...n with the AMPS and AC buttons Initially place the instrument on the 2A range select 5V2 digit resolution 2 Connect the AC calibrator to the Instrument as shown In Figure 5 4 Set the calibrator freque...

Page 82: ...in Make sure the display is in the 534 digit resolution mode also see that ZERO is disabled 3 Refer to Table 5 7 which summarizes the verification resistance values To check Model 195A accuracy at eac...

Page 83: ...ear panel terminals If the Model 1950 option is installed applied voltage and current signals are controlled or modified into the proper form and applied to the multiplexer The multiplexer applies the...

Page 84: ...ISOLATION 6 2 Figure 6 1 Basic Biock Diagram...

Page 85: ...a base value as an aid in computing the final displayed reading The 2V reference source which is shown in Figure 6 4 is made up of a highly stable zener diode an op amp and a resistive voltage divide...

Page 86: ...AMPLIFIER OP AMPS Figure 6 3 Simplified Schematic of the Input Buffer Amplifier...

Page 87: ...5 VreF 6 35 5 10 875 2V Figure 6 4 Simplified Schematic of the 2V Reference Source 614 4kHz CLOCK INPUT Figure 6 5 Simplified A D Converter Schematic 6 5...

Page 88: ...Hz Each time 02 goes high a counter in the microcomputer is incremented With a 16 6ms integration period the maximum number of counts is 16 6ms x 307 2kHz 5 108 counts At the end of the charge balance...

Page 89: ...SWITCH MATRIX INPUTS Figure 6 7 Simplified Microcomputer Block Diagram...

Page 90: ...processor Is capable of directly addressing a total of 64K 65 536 bytes of memory In hexadecimal nota tion these bytes are assigned contiguous addresses between 0000 and FFFF the dollar sign preceding...

Page 91: ...of the interface up to the normal IEEE maximum of 15 devices The GPIA simplifies MPU Interfacing to the IEEE bus because many control sequences take place automatically For exam ple when a write Is do...

Page 92: ...FETs on and off at the appropriate times 6 5 POWER SUPPLY For the following discussion refer to the power supply schematic number 195 106 at the end of this manual The power supply Is made up of a lin...

Page 93: ...nal are in memory the microcomputer calculates the displayed or IEEE value from the following formula 2 VgjQ Vzerq REF ZERO It can be seen that the zero error Is subtracted from both the signal and re...

Page 94: ...3 The sequences for the various ranges are similar with the first two phases being the same in all cases As each FET is switched on the voltage developed across that particular section of the voltage...

Page 95: ...gure 6 10 Resistance Measurement Simplified Circuit for 20 200kf2 Ranges Figure 6 11 FET Switching Sequence for 20Q 20012 and 2kQ Ranges Figure 6 12 FET Switching Sequence for 20kQ and 20012 Ranges 6...

Page 96: ...roduced into the reading By using a 4 terminal configuration as shown In Figure 6 15 the error can be reduced considerably Here most of the cur rent flows through the test leads represented by R and R...

Page 97: ...measurements option measurements are performed using a specific sequence Figure 6 17 shows the FET switching sequence for all option measurements During the first phase Q102 is on which means that the...

Page 98: ...hen used by the microcomputer to calculate the temperature Because the RTD current has a 25 duty cycle probe heating is reduced also the off cycle allows thermal voltages to be measured 6 8 1 RTD Resi...

Page 99: ...thin the microcom puter it is a simple matter to calculate the final reading Above 0 C these calculations are performed using the following relationships T A a2 4B 1 Rt Rol 2B Where A 1 t a 100 B a 6...

Page 100: ...START 3 TIMES Figure 6 20 FET Switching Sequence for RTD Resistance Measurements 6 18...

Page 101: ...Selection Switch Position 105 125V 50 400HZ 115V 210 250V 50 400HZ 230V 90 1 10V 50 400HZ 115V 195 250V 50 400HZ 230V Requires special power transformer CAUTION The correct fuse type must be used to m...

Page 102: ...op of the shield as shown in Figure 7 1 Line up the holes at the outer edge of the Model 1950 with the holes in the shield 4 Secure the Model 1950 with the long screws provided with the accessory Thes...

Page 103: ...cific probe If any of the calibration procedures in this section can not be performed properly refer to the troubleshooting infor mation in this section If the problem persists contact your Keithley r...

Page 104: ...tons in sequence 5 Key in the corresponding calibration value if different from the prompted value from Table 7 5 and press the ENT but ton or press PRGM to abort the calibration sequence this will no...

Page 105: ...d in paragraph 7 5 9 The PRGM light will flash until NVRAM storage is successfully performed 7 5 6 AC Voltage Calibration With Model 1950 Option To perform AC voltage calibration connect a precise AC...

Page 106: ...of inputs 2V range calibration must be done first at these tw o points in sequence for rated accuracy 7 5 7 AC and DC Current Calibration With Model 1950 Option Current calibration need only be perfor...

Page 107: ...procedure the instrument will prompt for a number of constants Table 7 9 summarizes prompt messages Along with each prompting message the display Figure 7 6 Current Calibration Connections will show e...

Page 108: ...ibration Jumpers Non volatile storage can be disabled to avoid inadvertently changing instrument calibration or operating parameters These two jumpers which are located on the mother board as shown in...

Page 109: ...the ribbon connector from its mating receptacle on the mother board B Disconnect the remaining five wires from the mother board C Remove the two screws at the outer edge of the shield carefully pull...

Page 110: ...roubleshoot elsewhere unless the ROMs are operating properly 2 Non volatile RAM Test If the NVRAM test fails the following message will be displayed I unCRL I This is a succinct message indicating tha...

Page 111: ...ows which switching FETs and relays will be on and what the buffer gain will be for various tests on different ranges and functions n test number This test procedure greatly simplifies troubleshooting...

Page 112: ...X100 Q109 RL1 N2 Q119 X100 Q114 RL1 N3 Q117 XI Q103 RL1 N4 Q117 XI Q114 RL1 20MJ2 N1 Q117 Q118 X2 Q111 Q115 RL2 N2 Q117 Q118 X2 QUO Q115 RL2 N3 Q117 Q118 X2 Q108 Q115 RL2 N4 Q117 Q118 X2 Q113 Q115 RL2...

Page 113: ...N1 Q117 XI Q102 Q501 Q504 K501 K504 Q505 K505 N2 Q117 XI Q114 1 i N3 Q117 XI Q103 N4 Q117 XI Q114 2VAC N1 Q117 XI Q102 Q505 K501 K504 N2 Q117 X1 Q114 Q505 K501 K504 N3 Q117 XI Q103 Q505 K501 K504 N4 Q...

Page 114: ...r amplifier a gain of X10 At the same time multiplexer FET Q1 13 is turned on During the N2 phase Q1 18 remains on but the multiplex er FET that is turned on is Q114 During the N3 and N4 phases the ga...

Page 115: ...raph 7 2 2 FI 01 Line Fuse Continuity Remove fuse to check 3 J1003 Line Power Plugged into live receptacle power on 4 5V Analog 5V 5 5V pad next to shield 5 VR102 Input 8V minimum Output of CR107 6 15...

Page 116: ...hecks Step Item Component Required Condition Remarks 1 Turn on power Select lOOOVDC range Initial power up test checks all display segments All voltages referenced to digital common 2 U203 pins 2 9 14...

Page 117: ...r amplifier output voltage at TP5 pin 6 of U137 5 Compare the required value with the listed value in the table 6 Repeat the procedure for each of the listed gain values NOTE All voltages In the troub...

Page 118: ...able Intervals IRQ line 10 U108 pins 2 9 0 to 4V 2ms pulses Display and NVRAM data Table 7 20 Model 1950 Option Checks Step Item Component Required Condition Remarks 1 Model 1950 Option Remove screws...

Page 119: ...C Voltage 1 9000VAC RMS 1kHz Calibration voltage 40 Range 2VAC 41 Program 8 n 1 42 TP5 1 9VDC Referenced to analog common 43 External AC Voltage 190mVAC RMS 1kHz Calibration voltage 44 Range 200mVAC 4...

Page 120: ......

Page 121: ...c and component layout numbers if applicable 5 Keithley Part Number 8 4 FACTORY SERVICE If the instrument is to be returned to the factory for service carefully pack the instrument see paragraph 1 9 a...

Page 122: ...TOP COVER 30540 OPTION SHIELD 1950 302...

Page 123: ...luminum Electrolytic 1 D4 E3 C 309 680 C124 Capacitor 33pF 500V Ceramic Disk 3 E3 C4 C 22 33P C125 Capacitor 3600pF 500V Polystyrene 2 B2 D4 C 138 3600P C126 Capacitor 10 tF 25V Aluminum Electrolytic...

Page 124: ...nel Selected 3 D4 C4 31841 Q116 FET N Channel 3 C4 C4 TG 128 Q117 FET N Channel 2 B2 C5 TG 128 Q118 FET N Channel 3 F3 C4 TG 128 Q119 FET N Channel 3 F4 D4 TG 128 Q120 Transistor Silicon NPN Planar 2N...

Page 125: ...Composition 3 E5 B5 R 88 10 7k R142 Resistor 7 5kfl 1 1 8W Composition 2 A3 C5 R 88 7 5k R143 Resistor 12 7kQ 1 1 8VV Composition 2 A3 C5 R 88 12 7k R144 Resistor Thick Film Network 3 C5 C5 TF 148 R1...

Page 126: ...U128 IC selected CA3086 2 BI D3 29198 U129 IC 8 bit Shift Register MC14094BCP 2 F3 A4 IC 251 U130 IC Quad Comparator LM339 2 G5 B4 IC 219 U131 IC Selected OP Amp 2 E3 C4 30167 U132 IC Selected CA3086...

Page 127: ...37 1 P1013 Connector male 9 pin 2 required E3 D2 CS 339 9 R165 Resistor lOkQ 5 1 4W Composition D1 D1 R 71 10k R166 Resistor 61 9kJ2 1 1 8W Composition Cl D1 R 88 61 9k R167 Resistor 267kQ 1 1 8W Comp...

Page 128: ...NP G4 D2 TG 90 0202 Transistor Silicon PNP G4 E2 TG 90 0203 Transistor Silicon PNP H4 D2 TG 90 0204 Transistor Silicon PNP H4 E2 TG 90 0205 Transistor Silicon PNP G4 D3 TG 90 0206 Transistor Silicon P...

Page 129: ...Relay A4 D3 RL 72 K505 Relay Reed SPST C4 C3 RL 57 K506 Relay Reed SPST C3 C3 RL 57 P1004 Cable assembly 14 Pin H2 E2 CA 31 2 P1008 Connector Pin A1 CS 236 P1009 Connector Pin E2 CS 236 P1010 Connecto...

Page 130: ...ty Location Keithley Part No Cover Bottom 1 Case 30541 Bail Tilt 1 Case 30544 Feet 4 Bottom Cover FE 14 Collar Insulating 4 Inside Bottom Case 30545 Spacer 2 Inside Bottom Case 31843 1 Cover Top 1 Cas...

Page 131: ...Figure 8 2 NVRAM Modifications Board Component Location Drawing Dwg No 195 160...

Page 132: ......

Page 133: ...Figure 8 9 Model 1950 AC Option Schematic Diagram Dwg No 1950 156 8 33 8 34...

Page 134: ...S209 TALK DS2I5 AC 08 R202A R202D R202C JR202H ISO I ISO I ISO i 150 DS2I0 LISTEN DS2I4 AMPS DS2I3 OHMS 02 DS2II REMOTE D DS220 PRGM 0 DS2I2 VOLTS 6 R202G R202B eR202E R202F ISO ISO ISO I ISO Qe Qf Qg...

Page 135: ...O NO REVISION DATE 8fc04 EuE4 e C AHZ B n az 9 84 c CCl T X UIIu CRiQS C I67 fi0e AOOdCi a 144 RIIbL R L 3l R U a CK n cRuL dia A d r vA E AOCiCD CliLo 01 0 7 1 OlOis wiTHtocrTt oeuCTec uio Rlto wAt i...

Page 136: ...RU RLg N C N C N C N C NA RELAY DRIVE UI39 1 5V Q KI02 KIOI N C N C N C N C N C 0 5V MODEL I NEXT ASSEMBLY j QT DO NOT SCALE THIS ORAWINO DIMENSIONAL TOLERANCES unless otherwise Specified OATEiilp g S...

Page 137: ...At R 27F 6 IM 5 iZ_2q2 RI27E UI42A R127D Tui 11 16 IM T 13 12 12 1 II STROBE CLOCK l 2288MHz TO UI2I PIN 2 ZONE B5 6I4 4KHZq_ T0UI25 PINI ZONE B4 UI21C 5V 9uI24B llQ 15 E r1 5 Vpp 3 He ZONE LTR ECONO...

Page 138: ...OFARADS 3 DENOTES DIGITAL COMMON 4 DENOTES ANALOG COMMON 5 O denotes front panel control 6 DENOTES REAR PANEL MOUNTING ANAl G 7 DENOTES INTERNAL ADJUSTMENT 8 rh DENOTES CHASSIS CONNECTION 9 T DENOTES...

Search results

Summary of Contents for 195A

Reviews:

Related manuals for 195A

Brands by name

Popular brands

Keithley 195A, Instruction Manual

Search results

Summary of Contents for 195A

Reviews:

Related manuals for 195A

Brands by name

Popular brands