HP-17950A-Manual-X-Y-Trace-Generator 电路图.pdf

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1、c 0 en . . 0. :a: OPERATING AND SERVICE MANUAL X-Y TRACE GENERATOR 17950A RadioFans.CN 收音机爱 好者资料库 HP Archive This vintage Hewlett Packard document was preserved and distributed by Please visit us on the web ! Prepared by on-line curator: Tony Gerbic For FREE Distribution Only * RadioFans.CN 收音机爱 好者资

2、料库 OPERATING AND SERVICE MANUAL MODEL 179SOA XY TRACE GENERATOR Serial Prefix 812 Copyright HEWLETT-PACKARD 1968 433 NO. FAIR OAKS AVENUE, PASADENA, CALIFORNIA Printed MAY 1968 RadioFans.CN 收音机爱 好者资料库 Section I II III IV v VI TABLE OF CONTENTS GENERAL INFORMATION 1-1. Description . . . . . 1-3. Manu

3、al Identification . 1-5. Specifications . . . INSTALLATION AND INSPECTION 2-1. Incoming Inspection . 2-5. Storage . . . 2-7. Shipping . . 2-9. Battery Installation . 2-11. Battery Check . OPERATION 3-1. Introduction . . 3-3. Electrical Requirements . . 3-5. Operating Controls . . . . . 3-7. Operatio

4、n . 3-9. Damping Function . . . PRINCIPLES OF OPERATION 4-1. General Circuit Description . . . 4-3. Simplified Circuit Description . 4-5. Detailed Circuit Description . MAINTENANCE 5-1. Preventive Maintenance . 5-4. Calibration . 5-6. Troubleshooting . . REPLACEABLE PARTS 6-1. Introduction . 6-3. Pa

5、rts List . . . . . . . . . . 6-5. Recommended Spares . 6-7. Component Identification . 6-9. Ordering Information . Page 1-1 1-1 1-1 2-1 2-1 2-1 2-1 2-1 3- 1 3-1 3-1 3- 1 3-1 4-1 4-1 4-1 5-1 5-1 5-1 6-1 6-1 6-1 6-1 6-1 ILLUSTRATIONS Figure Page 1-1. Model 17950A X-Y Trace Generator . . . . . . . . .

6、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-0 2-1. Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2-2. Incoming Inspection Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7、 . . . . . . . . . . . . . . 2-2 3-1. Operating Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 4-1. Simplified Circuit Diagr am . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 5-

8、1. Calibration Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 5-2. Troubleshooting Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 6- 1. Model l 7950A Replaceable Part

9、s List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 6-2. One Year Isolated Spare Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 6-3. Model l 7950A Bottom View of Interior. . . . . . . . . . . . . . . . . . . .

10、. . . . . . . . . . . . . . . . . . . . 6-3 6-4. Model 17950A Main Printed Circuit Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 6-5. Model 17950A Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 ii

11、FIGURE 1-1. MODEL 17950A X-Y TRACE GENERATOR 1-0 SECTION I GENERAL INFORMATION 1-1. DESCRIPTION. 1-2. PURPOSE AND CAPABILITY. The Hewlett- Packard Model 17950A X-Y Trace Generator is a self-contained ramp and step-function generator for checking dynamic performance of Hewlett-Packard X-Y Recorders w

12、hich have an input impedance NOT LESS THAN 20K ohms. This unit will drive any numb er of recorders simultaneously provided their combined parallel input impedance is NOT LESS THAN 20K ohms. The dynamic performance check supplements the basic calibration of recorders with a voltage standard, by sweep

13、ing both axes of the recorder simultaneously through their dynamic range. Five switch-selectable sweep rates and an OFF position are provided. Sweeping is controllable by a momentary-contact push-button. Sweep direction is reversible by toggle switches. A damping function provides an accurate, unifo

14、rm step-function voltage at the x output terminals for checking damping of any Hewlett-Packard Recorder. This function is selectable by a toggle-switch and controllable by a pushbutton. The use of a field-effect transistor and an integrated circuit amplifier provides reliability and low current drai

15、n. No external power source is required; power is sup- plied internally by two mercury batteries. 1-3. MANUAL IDENTIFICATION. 1-4. This manual applies to Model 17950A with serial prefix 812. The serial prefix is the first three digits of a two-part, eight-digit Serial Number (000-00000) used to iden

16、tify each Hewlett-Packard instrument. If the Serial Number is higher than 812, a change sheet supplied with the manual will define the difference between that model and the one described in this manual. Corrections to the manual, due to any errors that existed when it was printed are called Eratta a

17、nd appear on the change sheet (if any) supplied with the manual. For information pertaining to manual coverage of any Hewlett-Packard instFument, contact the nearest Hewlett Packard Sales/Service Office. 1-5. SPECIFICATIONS. SWEEP SPEEDS: 0. 02, 0. 1, 0. 2, 1, and 2 inches per second, with recorder

18、in 100/ mv per inch range. SWEEP ACCURACY: 5% of recorder full scale. LINEARITY: 0. 5% of full scale at room temperature (20C to 30C). OUTPUT VOLTAGE: Linear portion of output ramp begins at approx. 0 volts and extends to 1 volt (minimum). POWER SOURCE: Replaceable mercury batteries with minimum lif

19、e of 100 operating hours. REVERSIBLE TRACE: Sweep direction reversible by toggle switch. DAMPING FUNCTION: +4V. Step output for checking recorder damping, pushbutton switch operated. COMPATIBILITY: Model 17950A is compatible with all Hewlett- Packard X-Y Recorders whose input impedance is not less t

20、han 20K ohms, having a lOOmv/in. (40mv/cm or 50mv/cm) range. WEIGHT: Approximately 2 lbs. (net). DIMENSIONS: 5. 73 inches deep, 5. 00 inches wide and 3. 60 inches high. 1-1 SECTION II INSTALLATION AND INSPECTION 2-1. INCOMING INSPECTION. 2-2. MECHANICAL CHECK. If damage to the shipping carton is evi

21、dent, ask that an agent of the carrier be present during unpacking. Inspect com- ponents for mechanical damage, scratches, dents, broken knobs, etc. Also check carton and cushion- ing material for signs of severe stress. 2-3. PERFORMANCE INSPECTION. Electrical per- formance should be verified as soo

22、n as possible after receipt. The incoming inspection chart (Figure 2-2) is suitable for this purpose. 2-4. CLAIM FOR DAMAGE. If the 17950A is dam- aged, or fails to operate properly, notify the carrier and nearest Hewlett-Packard field office immediately. A list of field offices is given in the rear

23、 of this manual. Retain the shipping carton and padding material for inspection by the carrier. The field office will arrange for repair or replacement without waiting for settlement of a claim agains the carrier. 2-5. STORAGE. 2-6. Whenever the Model 17950A is not to be used for a considerable peri

24、od of time, it should be turned OFF, sealed in a moisture-proof covering and repackaged in the original shipping carton, or equivalent. 2-7. SHIPPING. 2-8. Before returning for any reason, notify the local field sales office of the difficulty encountered, along with all Model and Serial Numbers of i

25、nstru- ments or components involved, and they will furnish shipping instructions. When repackaging for ship- ment, it is important to wrap the instrument in heavy paper or plastic and surround with 3 to 4 inches of shock-absorbing material to cushion and prevent movement inside the shipping containe

26、r. The outside container should be sufficiently durable to prevent damage during rough handling. 2-9. BATTERY INSTALLATION. 2-10. This instrument is shipped from the factory with batteries not installed. Install batteries accord- ing to the following instructions: Remove four screws, one at each cor

27、ner of top plate. Remove bottom cover. (Refer to Figure 2-1). Looking at the bottom of the unit with the output jacks up, insert a battery into each battery holder with positive (+) terminal toward the output jacks. Connect the red lead from the small circuit board mounted on the selector switch to

28、the positive (+) terminal of the left hand battery; connect the black lead from the switch to the negative (-)terminal of the same battery. Connect the red lead from the switch to the positive (+) terminal of the right-hand battery; connect the black lead from the main (large) circuit board to the n

29、egative (-)terminal of the battery. Perform battery check, paragraph 2-11, before replacing bottom cover, to avoid repetition of dis- assembly in case a weak or dead battery has been installed. 2-11. BATTERY CHECK. 2-12. Connect a voltmeter across the 17950A X-or Y-output terminals. Set the 17950A t

30、o the fastest sweep rate (2 in/sec), with damping function off. Hold trace button depressed and read highest output voltage reached with trace reverse switch in down position. If less than 1. 75V, replace battery, (refer to paragraph 2-10), right-hand battery BT101, for positive sweep. If the voltag

31、e is 1. 75V or more in positive mode, but less than 1. 75V. in negative mode, replace left-hand battery, BT102 screws. Replace bottom cover and screws. 2-1 Specification Sweep Speeds Output Voltage Damping Function Linearity 2-2 FIGURE 2- 1. BATTERY INSTALLATION Inst. Required l/ X-Y Recorder with 2

32、0K min. input impedance setting X input range to IV / in will increase trace angle toward vertical. Turn Model 17950A sweep-rate selector switch to desired sweep-rate position; zero the recorder with recorder zero control. Move trace reverse switch downward for positive sweep, upward for nega- tive

33、sweep. Depress trace pushbutton to sweep. Release to stop sweep. 3-9. DAMPING FUNCTION. 3. 10. To check recorder damping, turn 17950A sweep-rate selector switch to 1 in/sec or 2 in/sec position and move damping function switch to ON. Set recorder axis to be checked to lV / in (. 4 v/cm or . 5 v/ cm)

34、; set other axis to 100 mv/ in. (40 mv/cm or 50 mv/cm). Connect 17950A X-output terminals to recorder axis to be checked. Connect Y -output terminals to other axis. Depress trace button, and while sweeping, momentarily depress damping pulse button. The damping pulse will deflect the pen about 4 in a

35、 positive direction, producing, with the sweeping of the other axis, a step. Recorder damping action will produce a pulse atop the lead- ing edge of the step. CAUTION: The circuit consumes battery power, sweeping or not, in all positions of the sweep-rate selector switch except OFF. Turn the switch

36、to OFF when not in use, for longest useful life of the batteries. 3-1 6 5 2 4 3 1. DAMPING FUNCTION. Switches the X output terminals to circuitry which produces a step-function output voltage when damping pulse button is depressed. (The Y output terminals remain connected to the sweep circuil.) 2. T

37、RACE. Starts the sweep when depressed, slops sweep when released. The pen remains at the point where the trace button is released. (The pen returns to zero when the selector switch is turned to OFF. The pen may also be returned by sweeping in reverse. See Trace Reverse. ) 3. OUTPUT CONNECTORS. These

38、 output terminals accept either open wires or banana type plugs. These terminals are connected. 4. TRACE REVERSE. The Trace Reverse switch reverses the input voltage polarity; the inverted output sweeps the recorder in the reverse direction when trace pushbutton is depressed. 5. SWEEP-RATE SELECTOR

39、SWITCH. This six-position rotary switch selects OFF and ON. Five sweep rates of 2, 1, 0. 2, 0. 1, and 0. 02 in/sec are selectable. 6. DAMPING PULSE. When depressed, this button causes a step-function of + 4 volts to deflect recorder pen for checking recorder damping. FIGURE 3-1. OPERATING CONTROLS 3

40、-2 SECTION IV PRINCIPLES OF OPERATION 4-1. GENERAL CIRCUIT DESCRIPTION. 4-2. Model 17950A consists of a dual power supply, attenuator, operational amplifier, and a feedback capacitor. The dual power supply makes possible the reverse trace feature of this generator, by applying input voltage of rever

41、sed polarity. The sweep-rate selector switch selects a precision attenu- ator resistor which determines the charge rate of the feedback capacitor. When power is applied, the capacitor begins to charge through the resistor. The amplifier reacts to the charging action and sends current to the other si

42、de of the capacitor, increas- ing the voltage across it. The current through the resistor is constant, and so the voltage on the capacitor, the output voltage, rises linearily. 4-3. SIMPLIFIED CIRCUIT DESCRIPTION. 4-4. When S1 is closed, C1 begins to charge through Rl. The amplifier senses the volta

43、ge caused by charging C1 and produces an output, V 0, of opposite polarity, sending current into the other side of C 1, tending to drive the amplifier input voltage back toward zero. The applied battery voltage continuously draws current from c1 through Rl, constantly presenting a small voltage to t

44、he amplifier input. The amplifier continuously reacts, constantly raising the voltage across Ci. which is the output voltage. 4-5. DETAILED CIRCUIT DESCRIPTION. 4-6. (Refer to schematic, Figure 6- 5). CR101 and CR103 provide Zener-controlled voltage regulation for the calibration resistors Rl02, Rl0

45、4, R105, R120, R122 and R123. Diodes CR-102 and CR-104, with resistors R103 and R121 provide temperature compen- sation for the zener diodes. Rl06 through Rl 10 are the precision attenuator resistors switched in indi- vidually to determine sweep-rates. ClOl is the feed- back capacitor. It discharges

46、 through Rlll when sweep-selector switch is in off position. QlOl is a dual field-effect transistor whose high input imped- ance draws no current from the charging circuit. C102, Cl03, R114 and R115 provide frequency com- pensation to stabilize the operational amplifier. When 8102, trace, is closed,

47、 a small voltage is applied to the ungrounded gate of QlOl, increasing or decreas- ing conduction in that half of the FET, and in R112 in series, depending on the position of 8103, positive RECORDERS INPUT TERMINALS FIGURE 4-1. SIMPLIFIED CffiCUIT DIAGRAM 4-1 or negative sweep. The polarity of the v

48、oltage applied to resistors R106 through RllO is reversed when S103, trace reverse, is switched. The resulting change in voltage across R112 constitutes a differential input to IClOl, which produces an inverted, amplified output to ClOl. Current flows through C 101 in a direction which tends to drive the amplifier back to zero. The battery continues to 4-2 draw current from ClOl through the selected attenuator resistor, keeping the amplifier input from a