KEI 225 Instruction 电路图.pdf

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1、Instruction Manual Model 225 Current Source Publication Date: August 1976 Keithley Instruments, Inc. Cleveland, Ohio, U.S.A. Document Nufnber: 29039 RadioFans.CN 收音机爱 好者资料库 WARRANTY Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1

2、 year from date of shipment. Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes. and documentation. During the Wmanty period, we will, at OUT option, either repair or replace any product that proves to be d

3、efective. To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio, You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs will be made a

4、nd the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance of the origi- nal warranty period, or at least 90 days. LIMITATION OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithleys express written co

5、nsent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCL

6、UDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE BUYERS 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 DAMAGES ARI

7、SING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERS

8、ON, OR DAMAGE TO PROPERTY. RadioFans.CN 收音机爱 好者资料库 CONTENTS MODEL 225 CONTENTS SP*CIFICATIONS- 1. GENERAL DESCRIPTION- 2. OPERATION- 3. CIRCUIT DESCRIPTION- 4. ACCESSORIES- 5. SER”ICING- lj. CALIBRATION- 7. REPLACEABLE PARTS- SCHrIC- 1 2 4 8 10 11 12 19 31 ii 3 RadioFans.CN 收音机爱 好者资料库 ILLUSTRATIONS

9、ILLUSTRATIONS I Figure NO. Title Page 1 Prone Panel. . 1 2 Front Panel Controls . 3 3 Rear Panel Controls. . 3 4 Connections. . 4 5 Resistive Load . 6 6 Currenf Sink . 6 7 Capacitive Load. . 6 8 Inductive Load . 6 9 Floating Supply. . 6 10 Volt Limit Characteristic. . 7 11 Modulation . 7 12 Block.Di

10、agram. . 8 13 Component Layout, PC-227 (Switch Board). . 13 14 Component Layauc, PC-228 (Mother Board). . 13 15 Component Layout, Switch 5101. . 14 16 Chassis - Top View . 14 17 Accuracy Check . 18 18 Regulation Check . 18 19 Modulation Check . 18 20 Inductive Load Check . 18 21 current Mode S Volta

11、ge Made Waveforms . 18 22 Top Cover Assembly . 21 23 Bortom Cover Assembly. . 21 I 0676 iii 4 CAUTION CAUTION MODEL 225 IF THE DECADE CURRENT DIALS ARE SET TO O-O-O and if the Output Selector switch is not at STANDBY, a COMPLIANCE VOLTAGE up to 100 volts may be present at the oucpuc terminals. For r

12、 25 watts. DIMENSIONS, WEIGHT: 5%” high x 8%” wide x 10” deep; net weight, 8 pounds. 225 CURRENT SOURCE .IWE 0571 6 1 GENERAL DESCRIPTION SECTION 1. GENERAL DESCRIPTION MODEL 225 1-I. GENERAL. The Model 225 is a current source with full scale ranges frarn 10-7 to 10-l ampere. 1-2. FEATURES. a. Resol

13、ution. The thpe decade dials plus a Trim potentiometer provides a resolution of .02% of full range. b. Compliance Voltage. A front panel Compliance Cantral provides a adjustable maximum compliance volt- see from 10 to 100 volts. c. Accuracy. The three decade dials adjust the out- put current to +.05

14、% of full range and +.5% of reading. d. Polarity. The OUTPUT SELECTOR Switch provides polarity selection without changing connections c the load. e. Floating Capability. The instrument LOW can be floated up t 2500 volts above chassis. f. Modulation. The tput current can be modulated over a frequency

15、 range from 50 t 500 Hz. TABLE l-l. Front Panel Controls CQtrOl Punctianal Description Paragraph Power Switch (S202) Controls line power to instrument. Decimal point serves 2-4, a as a pilot lamp. OUTPUT SELECTOR Switch (SlO5) Selects positive or negative polarity or standby pasitio. 2-4, b VOLTAGE

16、COMPLIANCE Control Sets the maximum compliance voltage which can be developed 2-4, c (R117 at the OUT terminal. LIMIT Indicator (DSlOl) When lighted, the instrument is in Voltage mode. 2-2, e Range Switch (SlOl) Selects the full scale range. The decimal point is auto- 2-4, d matically positioned by

17、the Range switch. Selectar Switches (S102, Selects the magnitude af current in 3 decade positions. 2-4, e s103, SlO4) FINE Control (R13S) Adjusts current. 2-4, f FILTER Switch (5106) When set to ON, the switch connects a 1 p capacitor 2-4, s at the OUT terminal. TABLE 1-2. Rear Panel Controls end Te

18、rmirals Control or Terminal Functional Description Paragraph Power Cord (P201) Pravides line power to instrument. LINE VOLTAGE Switch (S201) Sets instrument for 117 or 234 V line operatia. FUSE (F201) Type 3AG. slow slow. 117 v: 1,4A; 234 Y: l/S4 2-1, a OUT Receptacle (3104) Output high cannectio. 2

19、-1, a LOW Terminal (5201) Output law connection. 2-1, a GROOND Terminal (520) Ground (chassis) connection. 2.1, a !4ODUlATE Receptacle (5101) Connection to modulation transformer. 2-1, b Shorting Link Provides cbnnection between LOW and GROUND. 7 7 0571 MODEL 225 GENERAL DESCRIPTION 0571 3 8 OPERATI

20、ON MODEL 225 SECTION 2. 2-l. CONNECTIONS. 8. OUtPUt conneerors. 1. Front Panel. The connectors on the front panel are BNC type receptacles (Keithley part no. cs-15). The OVP receptacle (5103) provides conr,ec- tion to the Model 225 Output High. (The center terminal is Output High while the outer shi

21、eld is connected to chassis ground.) Connections to the output load can be made using the OUT receptacle when the Model 225 is not floating. (For a more complete discussion of floating operation, refer to paragraph 2-2 f.) The LOW receptacle (JlO5) provides a connection to the Model 225 Output Low.

22、(The center terminal is Output Low while the outer shield is connected to chassis ground.) 2. asac Panel. The OUT receptacle on the rear panel is also a BNC type. Connections can be made to either the front panel receptacle s the rear panel receptacle with satisfactory results. The rear panel LOW te

23、rminal (3104) is a binding post (Keithley part no. BP-1lG) which is connected to the center terminal of 5105 (on the front panel). The rear panel GROUND terminal (3201) is a binding past (Keithley partno. BP-118) which is connected to chassis ground. The shorting link (supplied) permits LOW to chass

24、is ground connections. b. Modulate Connector. The NOD”UTE receptacle 0101) is a BNC type connector (Keithley part no. CS- 15). This connector can be used for modulating the output current using an ac modulation signal. The center terminal is connected to a transformer-coupled modulation circuit whil

25、e the outer shield is connected to chassis ground. c. Cables. Connections should be made using co- axial cables which are low-noise types with graphite coating between dielectric and shield braid. For custom length cables, Keithley Part No. SC-9 Low Noise Coaxial Cable should be used. A mating BNC c

26、onnector is available by ordering Keithley part no. CS-44. OPERATION 2-2. MEASUREMENT CONSIDERATIONS. a. Accuracy. The accuracy is specified in terms of the front panel dial setting or reading as well as the full range selected. (The FINE current control must be set to “0” position to obtain the sta

27、ted accuracies.) Since the total accuracy of the Model 225 is the s of the readina accuracy and the full a accuracy, the user should select the lowest full range for best possible accuracy. Table 2-l. shows the total accuracy for typical dial settings. (The accuracy on the lOOkA range is +.05% of 10

28、00 or o.s”A plus 2.5% of 1000 or %A for a coca1 of 5.5nA.) TABLE 2-l. Accuracy For Typical Dial Settings Output Decade Dial RANGE Total Accuracy lhrL-elLt setting Setting (FINE c0ntr01 set to “0”) 1 x lo-6A o-o-1 1000 n 2 x log n 2 x lOlOG 2 x 1OlI R 2 x l0l2 “, “, : :;12 n TABLE 2-2. Output Impedan

29、ce Range setting O”tput Impedance* 100 m.4 10 mA 1000 liA 100 ,A 10 UA 1000 nA 100 nA *With Filter switch set to off. I For the 100 mA range, R, = 103n and % regulation = 0.005% since I regulation = 100 x RL I 1 qq Then % - The Model 225 will deliver the dialed current for a load resistance from 0 o

30、hms to WK. The value of w is determined by the dialed current I and the compliance voltage setting VC where Rw.K = WI. If the load resistance exceeds RMAx then the Mcdel 225 will automatically switch into Volt- age Limit mode indicated by the LIMIT lamp (DSlOl). f. Floatiw Operation. The instrument

31、can be floated “I) to +500 volts off chassis nround with less than 5 ppm of-full range change in that is, nA, IJA, and mA. The full range is determined by the position of the lighted decimal point end the designated engineering unit. e. Selector Switches (SIOZ, SlO3. S104L. These switches select the

32、 magnitude of the o”tput current in three decades. The position of the dials determines the significant digits from O-O-O to V-9-9. f. FINB Control (Rl38)-. This control is the inner dial of a dual concentric control. The fully clock- wise position “10” represents 1 digit added t., the right-hand di

33、al (S104). The fully counter clockwise position is the “0” or off position. When the FINE Control is set to “0”. the output current is determined only by the calibrated dials within rated specifica- tion. This control cm be used to “trim” the output current to within +.02% of full range, although th

34、e trim dial is adjustable t., within 2.005% of full range. NOTE For example, if the three decade dials were set for 9-9-9 on the 1000 !,A range, then the FINE control could be set to 1500 clockwise to obtain a current .Y”tp”t of approximately 999.5 +4. Since the stabilitv specification is +.02% (or

35、better) of reading, the useebie resolution w are rated at 300.vol of -12v + O.OlV. Ripple should be less than 3 mV p-p. Voltage should be +12V +o.ZW. Ripple should be less than 3 mv p-p. Voltage should be -lOV +lV. Voltage should be +lOV +V. Adjust for 0 20.1 mv. Adjust for +,.ov 20.5 SIV. Voltage c

36、hange must not exceed 1 mv. Adjust for voltaSe be- tween 27 mV to 40 mv. poten- tiometer R226. PC-228 PC-228 PC-228 PC-228 Poten- riometer R144. PC-228 Poten- tiometer RlS2. PC-228 14,16 -12V 14.16 +12V 14316 -lOV 14,16 +lOV 14.16 - 14.16 - 14.16 - 24203E 242038 242032: 24203E 24204E 24204E 242043 1

37、6 19 0571 MODEL 225 CALIBRATION TABLE 6-2. (CONTD) Para. Specification 6-4 or Adjustment Description Sub- Test Schematic Measurement Assembly Figure Point Part No. Compliance Voltage Limit Lamp Set range to mA. Set decade dials Adjust for PC-228 14,16 COMNON 24204E to 9-9-9. Set FINE to 10. Set volt

38、age Of potan- COMPLIANCE to 100. Set OUTPm to 1Ol.V +10 tiorseter + STANDBY. Connect Digital Volt- mV. R116. meter (A) between range switch shaft (12V eonrmon) and LOW. Connect load resistor. Adjust potentiometer R116 for 1Ol.V +lO mv. Set range to mA. Set decade dials to 9-9-9. set FINE to 10. set

39、COMPLIANCE to 10. Set OUTPUT to + STANDBY. Connect Oscilloscope (E) to OUT. Oscilloscope settings: 2mVldiv SmS/div Trigger = INTERNAL Input = AC COWLED Connect load resistor. Set OUTPW to +. Adjust potentiometer R203 such that the LIMIT lamp turns an when the 225 changes from current mode to voltage

40、 mode. PC-228 14,16 - 24203E Poten- tiometer R203. NOTE: To determine the crowover point between current and voltage modes, adjust the COMPLIANCE con- trol until the oscilloscope ripple waveform changes as shown in Figure 21. Set OUTPCT to -. Adjust potentiometer PC-228 R207 such that the LIMIT lamp

41、 turns Poten- on when the 225 changes from current tiometer mode to voltage mode. R207. 24203E 0571 20 17 i CALIBRATION MODEL 225 - FIGURE 17. Accuracy Check FIGURE 18. Regulation Check I - I I LLOSCOPE OSCILLOScOPE MILLATOR osc XIVPP L 225 OUT 0 OUTPUT 225 IOOHz ?A00 IS 40% OF F.S. Zk RF- 5-e sr. 1

42、4 Rl-2.2k 14 RI-56k 14 Rl-lOk 14 Comp camp Camp 01121 E8 RI-lk 14 01121 01121 01121 01121 01121 01121 01121 01121 TRANSISTORS Mfr. Code 04713 04713 04713 MOT 04713 02735 02735 04713 02734 02734 ES CEA lNS115 CR.4 CSA CEA EL3 E8 RR Rl-1Ok 14 Rl-47k 14 Rl-56k 14 Rl-47k 14 Rl-lk 14 Rl-l.Sk 14 Rl-12 14

43、RES-6.04k 14 RPSO-lk R-17-Iti 14 R88-2.21k 14 RSS-20k 14 RS8-20k 14 Rl-lOk 14 Rl-120 14 Rl-100k 14 CiTC”if _ IZSLR. Q201 Q202 Q203 Q204 PNP, TO-92 Case Q205 9206 Q207 QZOS 9209 Q210 Desis. 2N3905 MM4003 2N3905 25087 2N3905 40346 40346 MM4003 40317 40319 Keithley Fig. Pact No. Ref. l-G-53 14 TG-59 14

44、 TG-53 14 TG-61 14 TG-49 14 TG-44 14 TG-44 14 TG-59 14 TG-43 14 TG-50 14 28 0675 31 r 0 1 P G I P e r I I I )I I I I Oi t I L I I I I I I I I I I I I I I I I .O I / I /n I .& I 1 I I 0 I 7 / I -i - SERVICE FORM Model No. Name Company Address City Serial No. State P.O. No. Date Phone Zip List all con

45、trol settings and describe problem. (Attach additional sheets as necessary.) Show a block diagram of your measurement system including all instruments connected (whether power is turned on or not). Also describe signal source. Where is the measurement being performed? (factory, controlled laboraton/, out-of-doors, etc.1 What power line voltage is used? V