HP 463A User's Manual
Contents
1. OFF Switch When depressed this switch dis connects the instrumentfrom the external power source Itisinterlockedwiththe GAIN switches 2 LINE light This light will be lighted when the in strument is connected to a power source and the OFF switch is in the extended position GAIN switches Whendepressed these switches determine the amount of gain for the amplifier Depressing one GAIN switch turns the instrument on ADJ switch For variable gain onany range this switch and the gain range switch mustbe depressed 8 ADJUSTABLE ALL RANGES This potentiometer adjusts the gain on any range from zerotoa maxi mum of that GAIN indicated on the depressed fixed gain button 8 OVERLOAD light This light is onwhen the output current exceeds a specified value nominally set at 65 to 70mA or if theamplifieris inoperative 7 RESET switch When the OVERLOAD light glows this switch when depressed and released will return the amplifier to operation If the OVER LOAD is still present the light again glows DC Coupled INPUT This direct coupled input terminal provides gain from dc to the high fre quency cutoff of the 463A For ultimate de gain accuracy do not place the 463A in a draft AC Coupled INPUT This terminal provides a 3 0 coupling capacitor with low frequency cutoff at 0 5 Hz fixed gain 10 Hz adjustable gain Common Connector This common terminal is input2. OPERATING AND SERVICE MANUAL HP PART NO 00463 90001 MODEL 463A i PRECISION AC AMPLIFIER SERIALS PREFIXED 738 Appendix C Manual Backdating Changes adapts this manual to Serials Prefixed 624 738 00240 and below 738 00280 and below pr 419 42 T E MAINT Copyright Hewlett Packard Company 1968 P O Box 301 Loveland Colorado 80537 U S A siae 01798 1 Printed JAN 1968 Table of Contents TABLE OF CONTENTS Model 463A Section Page I GENERAL INFORMATION 1 3 1 1 Introduction e ea E 1 3 1 3 Description 4 1 3 1 7 Applications 1 3 1 9 Accessory Equipment Supplied 1 3 1 11 Instrument Identification 1 3 Section Page Tl INSTALLATION eec c n n n Bal 2 1 Introduction 4 2 1 2 3 Initial Inspection 2 1 2 5 Power Requirements 2 1 2 1 Grounding Requirements 2 1 2 10 Installation m 2 1 2 12 Bench Mounting 2 1 2 14 Rack Mounting eee 2 1 2 16 Repackaging for Shipment 2 1 Section Page IM OPERATING INSTRUCTIONS 3 1 3 1 Introduction saa e ioa eee 3 1 3 3 Description of Controls 3 1 3 5 Operational Instructions 3 1 3 6 Turn On Procedure 3 1 3 8 Front Panel Zero Adjustment 3 1 3 10 Selection of Input Terminal 3 1 3 12 Selection of Gain
3. citive coupledinput eachwithahighinput impedance The input is protected up to 150 V and the common terminal can be floated 500 V above chassis 1 5 The hp Model 463A Precision Amplifier has three ranges of voltage amplification 10 100 and 1000 The output of all three of these ranges maybe adjustedfrom zeroto a maximum indicated on the de pressed fixed gain button This is accomplished by alsodepressing the ADJ button ofthe switch and posi tioning the ADJUSTABLE ALL RANGES control 1 6 This Precision Amplifier has again accuracy of 0 01 from 10 Hz to 10 kHz on the X10 range The accuracy decreases with higher gainandat the highest and lowest frequencies see Table 1 1 for specifica tions The low distortion low noise and long term Stability make this instrument a desirable multi purpose laboratory amplifier 1 7 APPLICATIONS 1 8 The features of this amplifier listed under specifications and described in this section make it applicable to the following uses a Precision ac wideband voltage amplification 01798 1 INFORMATION b Isolationamplifierfor Thermocouple transfer measurements c Preamplifier for low level precision voltage measurements d Amplify oscillator outputs e Sensitive bridge measurements f Precision voltmeter calibration systems Attenuator calibration as much as 110 dB See Section III for detailed applications 1 9 ACCESSORY EQUIPMENT SUPPLIED 1 10 The additi
4. 100 1000 with an adjustable control for all ranges The front panel ZERO control adjusts the output to zero with the de input shorted 4 5 GENERAL DESCRIPTION 4 6 The Model 463A has the following assemblies Preamplifier and Shaping Amplifier Al Driver Amp lifier A2 Output Amplifier A3 Power Supply and Current Limiting A4 and the Switch Assembly A6 These assemblies are interconnected bya main board assembly A5 4 7 The input signal is either sent directly to the preamplifier through a capacitor tothe preamplifier or ifthe adjustable switch is depressed it is sent to anadjustable gain potentiometer where a portionor all of the input signal can be sent to the preamplifier 4 8 This input and the feedback signal from the output attenuated according to the gain button de pressed are compared by the dual differential pre amplifier The exceptional gain accuracy and low distortion of the amplifier is dependent on this input differential preamplifier The 20 dB differential amplifier actually is the summing junction of the overall feedback loop This summing junction has very good common mode rejection low distortion characteristics and good dc characteristics as it is a direct coupled amplifier 4 9 Following the preamplifier is a 40 dB shaping amplifier This section in addition to giving 40 dB of forward gain changes its high frequency gain char acteristics on the different gain ranges in order to mainta
5. 2 01798 1 Model 463A BUCKING SOURCE oo DOO Section HI SWITCH POSITION FUNCTION THERMOCOUPLE 1 PLUS DC REVERSAL 2 MINUS DC J ERROR CHECK 3 AC TEST SIGNAL Figure 3 2 Low Level Precision Thermal Transfer Measurements Table 3 3 hp Models 463A 3440A 3445A Combined Accuracy 463A 3440A F S GAIN SENSITIVITY With the 3445A on 10 Volt Range AC DC Range Unit The Combined Accuracy Speci fications are as shown above 3 28 The Model 463A Precision Amplifier may be used to amplify a low level signal so that it can be measured by the Model 741B Table 3 4 showsthe Combined Accuracy Specifications for the two instru ments 3 29 CALIBRATING VOLTMETERS AND ATTENU ATORS 3 30 The 463A can be used to increase the range of calibration systems for both voltmeters and attenua tors When used as a post amplifier with the E02 738BR Voltmeter Calibration System the output of the 652A oscillator can be increased up to 100 volts Combined Accuracy Reading Full Scale 2 Counts 100 kHz linearly de rate of full scale from 50 kHz to 100 kHz rms from 10 Hz to 100 kHz Attenuators may be calibrated for as much as 110 dB by using both the input and the output of the 463A Amplifier Since Some measuring instruments are degraded inaccuracy at very low levels it is more desirable toaccurately amplify the unknown and meas
6. AC Differential Voltmeter Resolution 10 uV hp Model 741B AC DC Differential Voltmeter DC Standard DC Null Voltmeter Resolution 100 uV Accuracy 2 of end scale 40 1 pV hp Model 419A DC Null Voltmeter DC Differential Voltmeter hp Model 741B AC DC Differential Voltmeter DC Standard A Voltmeter ranges 1 V to 100 V Resolution 5digits Accuracy 0 02 AC Voltmeter hp Model 403A B AC Voltmeter Battery operated Resolution 0 001 volt rms AC Inductive Divider ESI Model DT72A Deka tran Accuracy 10 1 ratio 10 ppm 100 1 ratio 100 ppm 1000 1 ratio 1000 ppm Input Voltage 100 volts AC Metal Film Resistance Divider Build from parts listed in Paragraph 5 23 Accuracy of metal film resistors Wattage 1 2 W Distortion Analyzer hp Model 333A 334A Distortion Analyzer Frequency 1 kHz to 100 kHz Distortion 70 dB below fundamental hp Model 467A Power Amplifier Amplifier DC Source Range 10 GAIN Frequency 10 Hz to 100 kHz hp Model 175A Oscil loscope with hp Model 1750B plug in Oscilloscope Sensitivity Horizontal 1 usec cm 0 05 volt em to 20 volts cm with 10 1 probe Frequency 10 Hz to 100 Hz Dual Trace Variable Line Transformer 115 Vae power source Superior V116T Voltage Output 103 5 volts to 127 5
7. Coupled gt 10 kQ source or AC Coupled 4mV C referred to input GENERAL Input Output Terminals Front Panel 3 4 spaced banana terminals for input output and chassis Rear Panel BNCterminalsforinputand output Recessed three terminal power line connector Amplifier common may be floated 500 V dc above chassis Temperature Range 0 to 500C Power 1150r230V 10 50 to 1000 Hz approxi mately 50 W at full load 01798 1 Model 463A Section I SECTION I GENERAL 1 1 INTRODUCTION 1 2 This section contains general information con cerning the hp Model 463A Precision AC Amplifier Figure 1 1 Included are its specifications Table 1 1 general description outstanding features ac cessory equipment supplied instrument identification and some of the major applications 1 3 DESCRIPTION 1 4 The solid state hp Model 463A Precision AC Amplifier was primarily designedas a vide band ac amplifier with a bandwidth from 10 Hz to 100 kHz Since it is directly coupled throughout the amplifier this 463A can also be usedas a dc amplifier with dif ferentaccuracy specifications The outputof the 463A is rated at 5 watts continuous and is protected for a nominaloverload indicated by a front panel OVER LOAD light It has an output capability of 100 V rms with an output impedance of 50 mQ to 20 Q depending on the gain and frequency selection This Precision Amplifier has a direct coupled input and an ac capa
8. Location 6 7 6 8 Power Supply Schematic 6 6 8 01798 1 Model 463A Section I Figure 1 1 Model 463A Precision AC Amplifier Table 1 1 FIXED GAIN DC COUPLED X10 Range Accuracy DC to 10 Hz lt 0 3 10 Hz to 10 kHz 0 0195 10 kHz to 100 kHz lt 20 19 Distortion 100 V Output Full Load 10 Hz to 10 kHz 0 0155 10 kHz to 100 kHz lt 0 175 X100 Range Accuracy DC to 10 Hz lt 3 10 Hz to 20 kHz 20 19 20 kHz to 100 kHz lt 41 09 Distortion 100 V Output Full Load 10 Hz to 10 kHz lt 0 03 10 kHz to 100 kHz 0 1 X1000 Range Accuracy DC to 10 Hz lt 30 10 Hz to 20 kHz lt 0 356 20 kHz to 100 kHz lt 3 0 Distortion 100 V Output Full Load 10 Hz to 10 kHz 0 19 10 kHz to 100 kHz lt 0 5 FIXED GAIN AC COUPLED Identical to dc coupled except coupling capacitor causes a 0 01 berror 25 Hz to a 3 dB error 0 35 Hz 01798 1 Specifications ADJUSTABLE GAIN AC OR DC COUPLED Gain may be adjusted from 0 to 100 of the fixed gain range Distortion characteristics identical with fixed gain range TEMPERATURE COEFFICIENT FIXED GAIN Includes temperature coefficient and short term stability Deviation from calibration temperature INPUT CHARACTERISTICS Input Impedance Fixed gain 1 MQ 259 lt 35 pF Adjustable gain 50 ES lt 200 pF Maximum Input Voltage protected to 150 volts AC Coupling
9. Precision Amplifier Included are initial inspection procedures power and grounding requirements installation information and instructions for repackaging for shipment 2 3 INITIAL INSPECTION 2 4 This instrument was carefully inspected both mechanically and electrically before shipment It should be physically free of mars or scratches andin perfect electrical order upon receipt To confirm this the instrument should be inspected for physical damage in transit If the instrument was damagedin transit file a claim with the carrier Test theelec trical performance of the instrument using the pro cedure outlined in Paragraph 5 5 If there is damage or deficiency see the warranty on the insidefront cover of this manual 2 5 POWER REQUIREMENTS 2 6 TheModel463A canbe operatedfrom any source of 115 or 230 V 210 at 50 to 1000 Hz With the instrument disconnected from the ac power source move the slide switch located onthe rear panel until the desired line voltage appears onthe switch Power dissipation is approximately 50 W at full load 2 7 GROUNDING REQUIREMENTS 2 8 To protect operating personnel the National Electrical Manufacturers Association NEMA re commends that the instrument panel and cabinet be grounded This instrument is equipped with a three conductor power cable which when plugged intoan appropriate receptacle grounds the instrument The offset pin on the power cable three prong connector is the
10. capacitor 500 volts peak Noise rms referred to input GAIN RANGE lt 1k SOURCE gt 1k SOURCE X10 with input shielded 1 1 Section I Model 463A Table i 1 Specifications Cont d OUTPUT CHARACTERISTICS Maximum Output DC 100 volts 20 mA AC refer to curve below Ga i i TAG E oo j VOLTAGE ust IOOmA i oz wu ra HE Que ao EE aa 55 o lOmA ii 3 Liu ML LLULL LU LL i in iOHz 100Hz IkHz IOkHz 100k Hz IMHz FREQUENCY LOAD CAPABILITY Maximum Output Power 5 watts continuous Current Limit Nominal lt 20 Hz 30 mA peak gt 20 Hz 90 mA peak Minimum Resistance All Ranges 100 2 Maximum Capacitance capacitance drive capability of 463A is increased by adding a resistor in series with the output as indicated below GAIN SERIES MAXIMUM RANGE RESISTANCE CAPACITANCE No Limit 300 pF X100 X1000 OUTPUT IMPEDANCE No Limit GAIN OUTPUT IMPEDANCE OHMS RANGE DC to 10 kHz 10 kHz to 100 kHz 1000 pF No Limit 5000 pF X10 X100 X1000 SQUARE WAVE RESPONSE FIXED GAIN X10 40 Vp p 0 5 us rise time X100 80 V p p 1 us rise time X1000 200 V p p 2 us rise time PHASE SHIFT FIXED GAIN IN DEGREES 10 Hz to 10 0 003 mo kHz or 0 01 yr kHz DC ZERO STABILITY Short Term 23 C 1 C V br output Temperature Coefficient DC Coupled lt 10 EQ source 400 uV OC re ferred to input DC
11. common or groundfor either de or ac in put signal It is connected to common of 463A and to the inner chassis or shield 11 OUTPUT Terminals The highand common OUT PUT terminals contain the Amplified input sig nal according to the GAIN switches depressed i Terminal This terminal is connected to power ground and to the outer chassis 3 Shorting Bar When the shorting bar is open the 463A common terminal xb is connected toinnerchassisbutfloatingin respect to outer chassis or power ground b When the shorting bar is closed common 4 is con nected to power ground ZERO adjust This adjusts the de output volt age of the amplifier to zero when input is shorted 8 FUSE ac line fuse 0 8 A for 115 V 0 4 A for 230 V AC POWER Receptacle Three contact connector the offset connector is power ground 7 115 230 ac Volt Slide Switch Slide switch until the source voltage used is displayed on the switch OUTPUT BNC connector is connected in parallel with high and common sj OUTPUT terminals located on the front panel INPUT BNC connector is connected in parallel with the front panel DC coupled input Figure 3 1 Front and Rear Panel Controls 01798 1 Model 463A Section I SECTION Ill OPERATING 3 1 INTRODUCTION 3 2 This section contains instructions for the oper ation of the hp Model 463A Precision Amplifier It includes Figure 3 1 Frontand Rear Panel Controls Indicato
12. 3 1 3 14 Operation of Reset Button 3 1 3 16 Capacitive Drive Capability 3 1 3 18 Applications 3 2 3 20 Low Level Precision Measure ments 2 2 22 ee eens 3 2 3 22 High Voltage Oscillators and Function Generators 3 2 3 26 Low Level AC Measurements 3 2 3 29 Calibrating Voltmeters and Attenuators 2 eee 3 3 Section Page IV THEORY OF OPERATION 4 1 4 1 Introduction 4 4 a 4 1 4 5 General Description 4 1 4 14 Outstanding Features 4 1 4 17 Detailed Description 4 1 4 19 Preamplifier 4 2 4 22 Shaper Amplifier 4 2 4 24 Driver Amplifier 4 2 4 26 Power Amplifier 4 2 4 30 Load Protection at Turn On and Off oues ane ae s vx s eA 4 32 Power Supply 4 2 4 42 Shield and Ground Connections 4 3 Section V MAINTENANCE c4 eee es 5 1 Introduction Vus Test Equipment Performance Checks Front Panel Zero ET Overload Protection Check 2 DC Gain Check 4 1000 DC Gain Check 6 100 DC Gain Check 8 0 2 he Ed 1 dg o e gioooogucgocucgoco 3 Co Q2 Q9 Co CO tO DO 4 kao eA a 10 DC Gain Check AC Gain Accuracy Check Alternate Method for Gain Ac curacy 10 kHz to 100 kHz 10 O oocoooouoogcu 1 DO B2 MD A UI O Gain Range 5 5 5 26 Phase Angle of Outpu
13. 30 LOAD PROTECTION AT TURN ON AND OFF 4 31 The externalload connectedto the 463A is pro tected during turn on and turn off procedure from eur rent surges and voltage transients When relay A3K1 is de energized the relay contact points disconnect the output terminal from the amplifier When the 463A is turned on or the reset switch is pressed A3K1 is energized instantly closing the circuit to the coil of A3K2 and preventing the OVERLOAD light from glowing A3K2 does not energize for 400 ms or less due to the time constant for charging A5C1 At the end of this time the relay is energized connecting the Amplifier to the output terminal When the in strument is turned off both relays de energize in stantaneously 4 32 POWER SUPPLY 4 33 The Model 463A power supply consists of two identical sections One section regulates the 210 volts and the other section regulates the 210 volts Each section has an adjustable current limit control and a RESET switch ganged in one switch 4 34 The primary power can be used from a 115 volt or 230 volt ac source The source slide switch con nects the two primary coils in series for 115 volts and in parallel for the 230 volt source The fuse F1 inserted in the instrument when shipped is a 0 8 A 01798 1 Model 463A Slow blow used for 115 volts source If the instrument is used from a 230 volt source this fuse mustbe changed to 0 4 A siow blow Ll and L2 are used in the power
14. 98 1 Number Page 5 1 Required Test Equipment sssaaa 5 0 5 2 Parts and Diagram for 10 1 Output Divider 5 3 5 4 AC Gain Accuracy Adjustments 6 1 Board 2 Wu 466 ela owe de rei 7 1 Replaceable Parts 7 2 List of Nlustrations Page 1 1 Model 463A LIST OF ILLUSTRATIONS Number Number Page 1 1 Model 463A Precision AC Amplifier 5 7 Distortion Check on the 10 GAIN range 5 10 3 1 Front and Rear Panel Controls 3 2 Low Level Precision Thermal Transfer Measurements 4 1 463A Block Diagram 4 2 Power Supply Block Diagram and the External Load Protective Circuit 5 1 Overload Protection Check 5 2 DC Gain Accuracy Check 5 3 AC Gain Accuracy Check 5 4 AC Accuracy Check with 1 kHz as Reference uc xo es COE 5 5 Output Impedance Check 5 6 AC and DC Input Impedance Check iv 1 c oOooOooOooOooo aaa H MO org Co B2 OA Da re 4o Oo P DC Linearity Check 10 GAIN Range 5 11 Model 463A Adjustment Location 5 12 Troubleshooting Tree 5 14 Chassis and A6S1 Component Location 6 2 Ai Component Location 6 3 Preamplifier and Shaper Schematic 6 3 S1 Contact Location 6 4 A2 Component Location 6 5 6 6 A3 Component Location 6 5 6 6 Driver and Pover Amplifier Schematic 4 4 6 5 6 6 A4 Component
15. OF RESET BUTTON 3 15 When the OVERLOAD light glows it indicates an external current overload or a defect in the Amp lifier causing an internal current overload Under these circumstances depress the RESET button and hold depressed for approximately one 1 second If the OVERLOAD light glows againwhen RESET is re leased disconnecttheloadanddepress RESET again 3 16 CAPACITIVE DRIVE CAPABILITY 3 17 The capacitive drive capability of the 463A is increased by adding a resistor in series with the output as indicated on following page 3 1 Section III Table 3 1 Model 463A Capacitive Drive SERIES MAXIMUM RANGE RESISTANCE CAPACITANCE 300 pF No limit 1000 pF No limit 5000 pF No limit 3 18 APPLICATIONS 3 19 The following paragraphs list some of the ap plications for the 463A These include making low level precision measurements producing high voltage from solid state oscillators and function generators combining the 463A with digital and differential volt meters tomeasure low level ac signals and using the 463A to enhance calibration systems for voltmeters and attenuators 3 20 LOW LEVEL PRECISION MEASUREMENTS 3 21 Because of the low distortion good gain accuracy and high output levels the 463A Amplifier enhances the specifications of many existing instruments In the paragraphs following some of the combined speci fications are indicated for the 463A used with avail ableinst
16. X100 SHAPING i NETWORK Fo x10 SHAPING NETWORK X1000 Le 7 10062 Xo x1000 Figure 4 1 463A Block Diagram 210V SERIES REGULATOR 210V t 210V comparator fIOV AND AMPLIFIER 260v UNREGULATED SUPPLY hi TEN OVERLOAD usar T17 aov 1 LIGHT i SERIES i REGULATOR t i 4 i 2I0V i COMPARATOR i AND AMPLIFIER i RESET 260V I i UNREGULATED i SUPPLY i Ki i 1 f 1 210v CURRENT i pig El LIMIT Ld i o_o OUTPUT Ex aesa c 010 Figure 4 2 Power Supply Block Diagram and the External Load Protective Circuit 4 0 01798 1 Model 463A Section IV SECTION IV THEORY OF OPERATION 4 1 INTRODUCTION 4 2 Section IV contains information relating to the theory of operation of the Model 463A Block Dia grams are given in Figures 4 1 and 4 2 to which the general description is referenced The detailed description is referenced to Figures 6 3 and 6 7 Amplifier Schematics or Figure 6 9 Power Supply Schematic The general description is given first followed by the detailed description 4 3 The Model 463A is usable for amplifying fre quencies from dc to 100 kHz The accuracy and frequency response for a gain of 10 isgreaterthan 0 01 for frequencies from 10 Hz to 10 kHz The distortion for this frequency range and gain is less than 80dB or 0 017 The 463A hasexcellentac gain stability making it reliable for long term measure ments 4 4 Theamplifier provides three fixed gain ranges 10
17. entiometer and the wiper arm is con nected to the preamplifier The input impedance changes with the adjustable gain See Table 1 1 for specifications The output on the front panel consists of three terminals with a grounding strap When the grounding strap is open the circuit common or inner chassis ground is floating in respect to outer chassis or power line ground When the grounding strap is closed inner chassis is connected to outer chassis and power line ground Locatedon the rear panel are a de coupled input and a floating output which are BNC connectors Both are connected in parallel with the respective connectors on the front panel 4 19 PREAMPLIFIER 4 20 The Amplifier input signal or a portion of it selected by the adjustable gain control is applied to a Darlington differential amplifier along witha feedback signal from the Amplifier s output This differential amplifier is connected to another differential ampli fier for minimizing errors due to junctions and vari ations in components 4 21 The collector of A1Q1 isbootstrapped by AICR4 and the emitter is bootstrappedby AICR5for high in put impedance A1R9 adjusts a DC zero output read ing with open de coupled input terminalwhile R2 front panel ZERO ADJ provides a zero output signal with the dc coupled input terminals shorted A1R1l is an adjustment for common mode rejection of the input differential amplifier A1Q1 Q6 and A1R26 provides an adjustment for an internal ze
18. fier is then taken from the tap of this potentiometer 4 14 OUTSTANDING FEATURES 4 15 The 463A is protected for an input voltage of 150 volts The common terminal may be floated 500 volts above chassis ground The gain switching device provides for a momentary shorting to ground during change of gain range which prevents an erratic output at this time 4 16 Two major features were added to the basic amplifier to provide protection to both the amplifier itself and external equipmentused with the amplifier One is the time delay circuitry atthe output terminals This circuitry prevents the output signal from ap pearing at the output terminals until the power sup plies are stabilized at turn on and overload resets of the instrument Also providedis the current limit circuitry shown in the power supply diagram These Current limits are set to open the power supplies in the event too much current is drawn at the output terminalsor if an internal short within the amplifier occurs thus protection is provided at the output terminals and within the amplifier itself 4 17 DETAILED DESCRIPTION 4 18 Two inputs are provided on the front panel a de coupled input and an ac capacitive coupled in 4 1 Section IV put both use the same common terminal These in puts are connected directly to the preamplifier through the nonenergized contacts of A5K1 or they are con nected through the energized contacts to the adjust able gain pot
19. ground wire 2 9 To preserve the protection feature when oper ating the instrument from a two contact outlet usea three prong to two prong adapter and connect the green pigtail on the adapter to ground 2 10 INSTALLATION 2 11 The Model 463A is fully transistorized there fore no special cooling is required However the instrument should not be operated where the ambient temperature exceeds 50 C 122 F or the relative humidity exceeds 95 2 12 BENCH MOUNTING 2 13 The Model 463A is shippedwith plastic feet and tilt stand in place ready for useas abench instrument 01798 1 2 14 RACK MOUNTING 2 15 The Model 463A may be rack mounted by using the Rack Mount Kit hp Part No 00463 84401 In structions for the conversion are included with the kit The bottom cover of the 463A must be removed before removing the plastic feet Lay the instrument on its top and remove two screws from the bottom cover Slide cover toward the rear of the instrument and lift To remove feet depress button and move foot toward center of instrument and lift Replace bottom cover by reversing the removal procedure When mounted in a rack using the rack mount kit additional support at the rear of the instrument should be provided if vibration or similar stress is likely The rack mount is an EIA standard width of 19 inches 2 16 REPACKAGING FOR SHIPMENT 2 17 The following paragraphs contain a general guide for repackaging of the
20. he OUTPUT of the 463A to the input of a de voltmeter c Place the dc voltmeter on the range to be used d Adjust front panel ZERO screwdriver adjust to zero the tolerances listed below 10 GAIN range 1mV 100 GAIN range 10mV 1000 GAIN range 200 mV 3 10 SELECTION OF INPUT TERMINAL 3 11 The DC Coupled INPUT terminal must be used for a dc voltage or afrequency of 1Hz or less When used as a de amplifier for maximum accuracy and minimum de zero drift the 463A must have coversin place and not be in a draft AC Coupled INPUT with fixed gain is 3 dB at 0 5 Hz adjustable gain is 3 dB at 10 Hz The ac coupling capacitor will block de voltage if this is desired and the capacitor is pro tected upto an input of 500 volts peak The de coupled input is protected upto 150 volts The Commonter minal may be floated 500 Vde above chassis with the output grounding strap open 3 12 SELECTION OF GAIN 3 13 The gainof the Amplifiermay be10 100 1000 fixed gain or variable gain upto a maximum of any of these fixed ranges If the OFF button is depressed the amplifier will be turned on by depressing the de sired fixed gain button If again other than the fixed gain is desired the ADJ button must be pressed in addition to the desired fixed gain button The desir able output voltage is obtainedby adjusting the variable gain control This is a ten turn potentiometer with high resolution 3 14 OPERATION
21. ies a potential to the base of the Darlingtonconfiguration A4Q2 and Q3 The more current drawn the more positive the voltage becomes at the base of A4Q1 The cutoff point is adjusted by A5R28 When A4Q turns on A4Q2andQ3are turned off and the power supply is disconnected from the amplifier and the overload light glows Because of the positive feedback due to R8 and CR1 the circuit remains in this condition until the RESET switch is pressed and released 4 42 SHIELD AND GROUND CONNECTIONS 4 43 Circuit ground Y is connected to the inner chassis or shield Power ground is connected to the outer chassis or case of the instrument The only way these two grounds are connected is by closing the grounding strap on thefront panel OUTPUT terminals If it is desirable to ficat the circuit output above power ground this ground strap must be open 4 3 NOTES me hama type Mady Hut netin Vue m A Morte 44 50 0 Section V Model 463A Table 5 1 Required Test Equipment REQUIRED CHARACTERISTICS SUGGESTED MODEL hp Model 3300A Func tion Generator with plug in Square Wave triangular Function Generator Frequency 01 Hz to 10 kHz Output Voltage 10 volts p p Oscillator Frequency 10 Hz to 100 kHz hp Model 651A B Test Output Voltage 6 volts rms Oscillator open circuit DC Standard AC Differential Volt meter Standard Output 10 volts
22. in a wide bandwidth on all ranges 4 10 The next stage is a 20 dB output power ampli fier Primarily this amplifier was designed for the 01798 1 high voltage swing necessary for 100 V rms output This was accomplished by stacking five high voltage transistors so they share the swing in output voltage The push pull emitter follower output using six stacked transistors has high current capabilities with low distortion 4 11 Both the shaping amplifier and the output amp lifier arefeedback amplifiers withinthemselves This internalfeedback givesthe high gainaccuracy and the low distortion characteristics of each stage The overall feedback loop of the amplifier is closed through a precision feedback attenuator This attenuator is especially designed for good high frequency charac teristics low temperature coefficient and good long term stability This attenuator in the overall feed back loop determines the overall gain of the 463A amplifier 4 12 The 463A always maintainsa forward loop gain of 80 dB while the feedback varies from 20 dB to 60 dB depending on gain range selection Thus the highest gain range has the lowestfeedback or loop gain of the amplifier For this reason the best Characteristics are obtained on the low gain range where the highest loop gain is employed 4 13 The adjustable gain of the amplifier is accom plished by simply switching ina multiturn high reso lution potentiometer The input to the ampli
23. input to suppress R F signals which are passed to ground through C1 and C2 When the pri mary power is connected to the instrument the line light connected through SIR17 glows 4 35 210 V AND 210 V REGULATOR CIRCUITS 4 36 In this explanation the 210 V Regulator com ponent designators will be used as both circuits are identical Figure 4 2 shows the power supply block diagram and the external load protective circuits 4 37 The differential amplifier A4Q5 and the Dar lington configuration A4Q6 and A4Q7 senses a minute variation in the 210 volt output through a voltage divider adjusted by A4R16 The output of the differ ential amplifier is applied to the base of A4Q4 which isa current source forthe series regulator transistor A5Q1 see Figure 6 9 4 38 The 210 volt regulator has the series tran sistor between the most positive portion of the cir cuit and common ground An additional voltage 211 volts is taken from pin 13 of J4 for the overload light 01798 1 Section IV 4 39 CURRENT LIMIT CONTROL CIRCUITS 4 40 When the external current load increases be yond a set value or if the internal circuit is defective and the power supply draws too much current the power is disconnected automatically and the OVER LOAD light glows Pressing and releasing the RE SET switch restores the circuit to operation if the overload is removed 4 41 Transistor A4Q1 senses the current drawn from the power supply and appl
24. instrumentfor shipment Refer to Paragraph 2 19 if the original container is to be used 2 20 if it is not H you have any questions contact your local hp Salesand Service Office See Appendix B for office locations 2 18 the instrument is to be shipped to Hewlett Packard for service or repair attach a tag to thein strument identifying the owner and indicating the service or repair tobe accomplished include the model number and full serial number of the instrument In any correspondence identify the instrumentby model number serial number and serial number prefix 2 19 If original container is tobe used proceed as follows a Place instrument in original container if available If original container is not avail able one canbe purchasedfrom your nearest hp Sales and Service Office b Ensure that container is well sealed with Strong tape or metal bands 2 20 If original container is not tobe used proceed as follows a Wrap instrument in heavy paper or plastic before placing in an inner container b Place packing material around all sides of in strument and protect panel face with card board strips c Place instrument and inner container in a heavy carton or wooden box and seal with strong tape or metal bands d Mark shipping container with DELICATE INSTRUMENT FRAGILE etc 2 1 Section HI Model 463A
25. m 0 005 Hz to 10 kHz The 203A may also be used with two 463A s to generatea 200volt rmsbalanced output By connect ing one 463A to the reference phase sine wave output and the other 463A to the variable phase sine wave output set at180 degrees the amplitudes can be ad justed to produce a balanced 200 volt rms signal from the two outputs of the 463A having the output grounds connected together 3 24 The OUTPUT of the 3300A Function Generator can be connected to the DC direct coupled INPUT of the 463A Precision Amplifier to form a high voltage low frequency function generator The combined specifications are as follows Frequency Range 0 01 Hz to 100 kHz OUTPUT 100 V rms sine wave 280 V p p triangular wave 40 V p p square wave with 0 15 us risetime 3 25 These high voltage low frequency low distor tion signals may be used to provide power for servo loops for medical experiments and for geophysical measurements The sensitivity requirement on the null detector is decreased by having up to 100 volts rms available 3 26 LOW LEVEL AC MEASUREMENTS 3 27 The Model 463A Precision Amplifier may be used to amplify a low levelac signal so that it may bemeasuredby a 3440 Digital Voltmeter with a 3445A Table 3 2 Combined Accuracy of hp Model 463A and Holt 6A Transfer Voltmeter 463A Measurement Gain Level Reading ac de difference Frequency 100 kHz Noise of the 463A is added at lower levels 3
26. olts peak to peak The bias or voltage level for these stacked transistors are proportioned by a volt age divider A5R10 through A5R27 4 26 POWER AMPLIFIER 4 27 The voltage amplifier outputs are interlinked to the Power Amplifier which also uses stacked tran sistors A3Q1 through A3Q6 This power amplifier is a push pull emitter follower circuit used for high current capabilities with low distortion A portionof the output of the emitter follower is fed back to the base of A2Q4 driver differentialamplifier for stability of the output amplifier 4 28 The overallfeedback loop of the 463A amplifier is closed through a precision feedback attenuator This precision attenuator is made up of fourwire wound resistors A6S1R8 through A6S1R11 especially designed for good high frequency characteristics low temperature coefficient and excellent long term sta bility These characteristics of the attenuator de termine the overall gain characteristics of the 463A amplifier Variable resistorsand capacitors or fac tory selected values are located inthe attenuator feed back path for each gain range These are adjusted components for the extreme accuracy and frequency response of the 463A on each individual gain range 4 29 The output of the power amplifier is connected tothe front panel output terminals through the contact points of A3K1 The amplifier output is sensed at the front panel output terminals for low output impedance 4
27. onal equipment supplied with this instrument are listed in Table 1 2 Table 1 2 Equipment Supplied 8830 0032 Extractor PC Board included in rack mount kit Kit Rack Mount Fuse 0 4A S B 230 V operation 00463 84401 2110 0019 8120 0078 00463 90001 Power Cord detachable Manual Operating and Service 1 11 INSTRUMENT IDENTIFICATION 1 12 Hewlett Packard uses a two section eight digit serial number to identify instruments e g 000 00000 The serialnumber islocated on the rear panel of the instrument The first three digitsare the serial prefix and the last five digits refer toa specific instrument If the first three digits of your instrument serial number do not appear on the title page of this manual there are differencesbetween the manual and your instrument which are describedin change sheets included withthe manual The Manual Changes loose leaf change sheet contains errata and changes in instruments with a larger serial prefix or serialnumber than that on the title page of the manual If the change sheet ismissing the information can be supplied by your nearest Hewlett Packard field office The backdating sheet for previous serial prefixes is located in the appendix of the manual 1 3 Model 463A Section II SECTION II INSTALLATION 2 1 INTRODUCTION 2 2 This section contains information and instruc tions necessary for the installationand shipping of the hp Model 463A
28. ro at base of A1Q6 with the de coupled input shorted AICR1 AICR2and A1R1 provide an input protective device The single ended output of the preamplifier is taken from the collector of A1Q7 4 22 SHAPER AMPLIFIER 4 23 The shaper differential amplifier A1Q9 and A1Q10 compares the output signal from the preamp lifier and the signal from the shaper network deter mined by the GAIN switch depressed This output is appliedto thebase of A1Q11 and thence through A1Q12 13 and 14 through the GAIN switches to the Driver Amplifier A portion of each GAIN switch shorts the input of the Driver Amplifierto circuit ground during change of fixed GAIN This prevents transients on the Amplifier output due to GAIN switching 4 24 DRIVER AMPLIFIER 4 25 The output signal from the shaperamplifier and the feedback from the power amplifier is comparedin the two stage differential amplifier A2Q1 through A2Q4 The potentiometer A2R6 adjusts the Amplifier OUT PUT to zero without an input to the base of A2Q1 pin 18 of A5J2 The dc output from A2Q2 is made 175 volts more negative by A2CR1 through A2CR6 to pro vide for high voltage gain in the succeeding amplifier stage The output of the differential amplifier is Applied through A2Q5 emitter follower to the voltage 4 2 Model 463A amplifier A2Q6 through A2Q10 These high voltage transistors are stacked to divide the high voltage swing of the output which is rated for a sine wave at 280 v
29. rsand Connectors a Turn On procedure out put zero adjustment procedure and procedures for Specific applications 3 3 DESCRIPTION OF CONTROLS 3 4 Figure 3 1 shows the front and rear panels of the 463A with the description and function of the con trols indicators and connectors The components on the frontand rear panel are numerically keyed to the description 3 5 OPERATIONAL INSTRUCTIONS 3 6 TURN ON PROCEDURE 3 7 Before connecting the 463A to a power source positionthe 115 V 230 V slide switchfor an indication of the source voltage to be used IF THE 230 V AC SOURCE IS USED REPLACE THE 0 8 A FUSE WITHTHE 0 4 AFUSE ENCLOSED WITH THE INSTRUMENT a Connect the detachable power cable to the ac power receptacle located on the rear panel and to the power source b If the OFF button isdepressed it can be re leasedby pressing the X10 X100 or X1000 GAIN button NOTE The three GAIN buttons and the OFF button are interlocked so that only one is depressed at a time The 463A is turned on when the OFF buttonis in the extended posi tion c To insure maximum stabilization allow in strument to gate uni ten Eno TOM with shield covers in place an 3 8 FRONT PANEL ZERO ADJUSTMENT 3 9 Zero the 463A using the following procedure each time the GAIN rangeis changedand before using the instrument 01798 1 INSTRUCTIONS a Short the direct coupled INPUT tothe common terminals b Connect t
30. ruments Probably one of themost interest ing applications is using the 463A with commercially availabie thermal transfer voltmeters or with a thermocouple utilizing the circuitry indicated in Figure 3 2 where the input to the 463A would be the signaltobe measured The thermal transfer method is one of the most accurate ac measuring devices available The problem associated with this method is the input impedance which is approximately 200 Q pervolt Thislow inputimpedance ofcourse causes errors because of loading the circuit involved By utilizing the 463A as a preamplifier or isolation amp lifier with the thermal transfer voltmeter a high in putimpedance canbeachieved Indicated in Table 3 2 are accuracies that canbe achieved inactodc transfer measurements by using the 463A with commercially available transfer voltmeters or NBS calibrated thermocouples Model 463A 3 22 HIGH VOLTAGE OSCILLATORS AND FUNC TION GENERATORS 3 23 Since most solid state oscillators do nothave high level output signals the 463A can be used as a post amplifier Because of its low distortion using it in this fashion introduces very little distortion to the high voltage output signal Since the 463A Pre cision Amplifier is direct coupled and has a low fre quency response it can be used with a low frequency oscillator or function generator For instance used with the 203A an output of 100 V rms with less than 0 079 distortion can be achieved fro
31. t Check 5 6 5 32 Output Impedance Check 5 7 5 34 Input Impedance Check 5 8 5 36 Noise Check 5 8 5 38 Maximum Output Voltage and Cur rent Check 2 eee 5 9 5 40 Square Wave Rise Time 5 9 5 42 Distortion Check 5 9 5 44 Adjustment and Calibration Pro cedures 5 6 eae ee a ua 4a 5 11 5 46 Cover Removal 5 11 5 48 Power Supply Voltage Adjustment 5 12 5 50 Overload Protection Adjustment 5 12 5 51 Internal Zero Adjustment 5 13 5 53 AC Calibration Procedure 5 13 5 55 Troubleshooting e 5 14 5 56 Introduction 4 5 14 5 60 Servicing Etched Circuit Boards 5 14 5 63 Troubleshooting Tree 5 15 Section VI SCHEMATICS 2 ses 2s n n n 6 1 Introduction 6 3 Schematic Diagrams 6 1 6 6 Component Location Diagrams 6 1 Section VII REPLACEABLE PARTS 7 1 Introduction 7 4 Ordering Information 7 6 Non Listed Parts Appendix A CODE LIST OF MANUFACTURERS B SALES AND SERVICE OFFICES C MANUAL BACKDATING CHANGES LIST OF TABLES Number Page 1 1 Specifications e t n nm on 1 1 1 2 Equipment Supplied 1 3 3 1 Model 453A Capacitive Drive 3 2 3 2 Combined Accuracy of hp Model 463A and Holt 6A Transfer Voltmeter 3 2 3 3 hp Models 463A 3440A 3445A Com bined Accuracy eee 3 3 3 4 hp Models 463A and 741B Combined AGOUPACY 8 2 4 enis wd 798 d dejen d 3 3 017
32. ure it at a higher level The accuracy at the input of the 463A will depend on the accuracy of the measuring instrument at the higher level plus the accuracy of the amplifier Noise and distortion introduced in the amplifier also affect accuracy The 463A is advantageous in this application because of its low noise and distortion and its precision gain accuracy over a broadfre quency band 3 31 As can be seen from these examples the 463A can be used in a variety of applications from the most critical inaccuracy anddistortionto the general pur pose high gain applications Table 3 4 hp Models 463A and 741B Combined Accuracy 463A 741B F S GAIN SENSITIVITY Combined Accuracy Reading 0 01 Full Scale 20 Hz 30 Hz 50 Hz 100 Hz 400 Hz 5kHz 10kHz 20kHz 50kHz 100kHz 0 16 0 11 0 05 0 25 0 2 0 14 0 45 0 4 0 34 With 741B on 1 V range eng eh 463A noise contributes error as error 25 Ga where Fm is noise to signal ratio 01798 1 3 3 Section IV Model 463A 20DB8 GAIN 40DB GAIN 7 2008 GAIN TEST res oras oc XL le 0 suapine i i T AMPL AMPL P 2 us ac gt H ADJUSTABLE H xccl Lo GOL RANGES 1 EK ira i ES rs sor xiooo Momentary Time i SHAPING POSITIVE DELAY A NETWORK SHORTING RELAY 1 p i v
33. volts Power 100 W 230 Vac power source Voltage Output 206 volts to 256 volts Power 100W Superior V216 5 0 A 01798 1
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