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Contents
1. 10 Hook Up 10 Typical Constant Voltage Operation 13 Setting Current Limit 14 Typical Constant Current Operation 15 Constant Voltage Constant Current Characteristic 16 Connecting Two Power Supplies in Series 16 Connecting Two Power Supplies in Parallel 19 Page APPLICATIONS 20 General 20 Electronics Servicing 20 Electronics Manufacturing 20 Electronics Design Lab 20 Electronics Education 21 Battery Charging 21 MAINTENANCE 22 Fuse Replacement 22 Line Voltage Conversion 22 Adjustments 22 1743B Calibration 23 Instrument Repair Service 23 WARRANTY SERVICE INSTRUCTIONS 25 LIMITED TWO YEAR WARRANTY 26 SPANISH MANUAL2. 28 INTRODUCTION The B K Precision Models 1744A amp 1745A DC Power Supplies are high quality general purpose dc power sources They provide 0 35 volts dc output adjustable with both coarse and fine voltage controls for precise settability The current output is 0 10 amps adjustable with both coarse and fine current controls model 1745A Two large LED meters continuously monitor the output voltage and current model 1745A The VOLTAGE meter is green while the CURRENT meter is red model 1745A These models exhibit excellent regulation and low ripple characteristics The circuit design incorporates a pre regulator which greatly reduces internal power dissipation at low output voltages The styling is both attractive and functional These instruments may be used in constant voltage or constant current applications The crossover from constant voltage to constant current modes is smooth and automatic LED s indicate the CV constant voltage or CC constant current mode of operation In constant voltage applications a current limit may be preset When load variations cause the current to reach the preset limit the unit then regulates output current rather than output voltage Current limits are adjustable from 5 to 100 of maximum In constant current applications the maximum voltage may be preset When load variations cause current to drop below the regulated value the unit reverts to regulated voltage o
3. Accuracy 0 5 9 digits Model 1744A Voltmeter Range 0 to 40 V Accuracy 2 5 Ammeter Hi Range OtollA Lo Range 0 to 2 2 A Accuracy 2 5 POWER REQUIREMENTS Domestic 120 VAC 10 60 Hz International 120 220 230 240 VAC 10 50 60 Hz POWER CONSUMPTION Approximately 420 W or less at full load PROTECTION Reverse polarity protection Current limiting SPECIFICATIONS TEMPERATURE RANGE WEIGHT 27 Ib 12 25 kg Operation 0 to 40 C lt 75 R H Storage 15 to 70 C lt 85 R H ACCESSORIES SUPPLIED Instruction Manual Spare Fuse DIMENSIONS HxWxD 5 7 x 10 5 x 15 145 x 267 x 38 mm NOTE Specifications and information are subject to change without notice Please visit www bkprecision com for the most current product information Note 1 Important Even with noticeable Thermal Drift this high resolution power supply will be considerably more accurate than any standard three digit display bench power supply Thermal Drift Since this power supply has greater resolution than standard bench power supplies they are more susceptible to Thermal Drift Thermal Drift occurs on almost every type of power supply but is more apparent on high resolution types Thermal Drift results in the metering of the power supply to either slowly increase or decrease with the change in the power supply s internal temperature As the power supply outputs more power its internal temperature will increase
4. CB radios etc on the test bench Most automobiles and other vehicles use 12 volt electrical systems Although the electrical system is normally referred to as a 12 volt system actual battery voltage when fully charged is approximately 14 volts The power supply may be set to 14 volts for servicing equipment from vehicles with 12 volt electrical systems Some trucks use a 24 volt electrical system bench testing of equipment from these systems should be performed at 28 volts Some servicing applications require the injection of a variable dc voltage for certain tests such as checking the effect of AGC bias in a television receiver This requires an isolated dc power supply such as the Model 1743B 20 The equipment being tested may contain its own power supply and operate from ac power A dc voltage may already be present in the circuit One polarity of the power supply output is floated to an appropriate point in the circuit such as the emitter of a transistor The other polarity of the power supply output is then applied to another point in the circuit such as the base of that transistor Varying the power supply voltage then varies the dc bias on the stage and the effects may be noted A series limiting resistor is often used to protect the circuits from overdissipation ELECTRONICS MANUFACTURING In electronics manufacturing facilities the power supply is often used as a dc power source while testing and adjusting modules subas
5. Rotate the Coarse VOLTAGE control away from zero sufficiently for the CC indicator to light Adjust the Coarse and Fine CURRENT control for the desired current limit Read the current value on the Current LED display The current limit overload protection has now been preset Do not change the CURRENT controls settings after this step Remove the short between the and terminals and hook 14 at zero Read current limit value from meter CC indicator on 1743B DC POWER St PPLY Adjust to desired current limit Temporarily short Figure 5 Setting Current Limit OPERATING INSTRUCTIONS TYPICAL CONSTANT CURRENT OPERATION 1 Before connecting the device to be powered to the power supply determine the maximum safe voltage to be applied and set the VOLTAGE controls to obtain that voltage reading on the Voltage LED display Determine the desired constant current value Set the Coarse and Fine CURRENT control to minimum fully counterclockwise Turn off the power supply and connect it to the device to be powered Turn on the power supply The CC indicator should light Increase the Coarse and Fine CURRENT control setting until the desired constant current value is read on the display or set the current limit in advance before connecting the load as prescribed in the earlier Setting Current Limit procedure If the load current drops below the
6. an ac outlet B K Precision products are not authorized for use in any application involving direct contact between our product and the human body or for use as a critical component in a life support device or system Here direct contact refers to any connection from or to our equipment via any cabling or switching means A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause failure of that device or system or to affect its safety or effectiveness Never work alone Someone should be nearby to render aid if necessary Training in CPR cardio pulmonary resuscitation first aid is highly recommended 27 BK PRECISION 22820 Savi Ranch Parkway Yorba Linda CA 92887 www bkprecision com 2008 B amp K Precision Corp V090308 Printed in Taiwan
7. by strapping the red terminal to the green terminal as shown in Fig 3B OPERATING INSTRUCTIONS 17438 DC POWER SUPPLY 17498 DC POWER SUPPLY rng mont fp Being Powered B salle Grounded common with A ilie Grounded common with alls negative polarity positive polarity Figure 3 A and B Grounding Possibilities 11 OPERATING INSTRUCTIONS C No ground reference Equipment Being Powered Equipment Being Powered D IE Grounded not commom with Z negative or positive polarity Figure 3 C and D Grounding Possibilities 12 OPERATING INSTRUCTIONS c If an earth ground reference is not required the configuration of Fig 3Bmay be used The scheme in Fig 3C should also be used where it is not known whether the chassis is common with either the positive or negative polarity d If the chassis or common of the equipment being powered is separate from both the positive and negative polarity power inputs use the connection shown in Fig 3D 5 Observe proper polarity If the circuit being powered is not equipped with reverse polarity protection damage to the circuit can result from reverse polarity Use color coded hook up leads for convenience in identifying polarity red for and black for 6 Make sure that the hook up leads offer sufficient current capability and low resistance between the power supply and the circuits being powered TYPICAL CONSTANT VOL
8. causing the metering primarily the current to slowly increase As the power demand is deceased the power supply will cool causing the metering primarily the current to slowly decrease If the power supply remains with a constant output of power for more than fifteen minutes the power supply metering will remain constant and should not continue to drift CONTROLS AND INDICATORS INDICATORS Either the CC or CV and the LED indicators will be lit whenever the unit is operating thus serving as a pilot light The unit automatically changes from CV to CC operation when the preset current limit is reached 1 C C Constant Current Indicator Red LED lights in constant current mode Unit regulates output current at value set by CUR RENT controls 2 C V Constant Voltage Indicator Green LED lights in constant voltage mode Unit regulates output voltage at value set by VOLTAGE controls 3 GREEN LED Display 1745A 4 digit display continuously monitors voltage 4 RED LED Display 1745A 4 digit display continuously monitors current VOLTAGE CONTROLS 5 Coarse Control Coarse adjustment of output voltage Read value on GREEN LED display 6 Fine Control Fine adjustment of output voltage Read value on GREEN LED display CURRENT CONTROL 7 Coarse CURRENT Control Adjusts current limit in constant voltage mode Adjusts constant current value in constant current mode Current can be read from RED LED display 8 Fi
9. INSTRUCTION BK PRECISION MANUAL Model 1744A amp 1745A 0 35 V 0 10 A DC POWER SUPPLY With Dual Displays TEST INSTRUMENT SAFETY WARNING Normal use of test equipment exposes you to a certain amount of danger from electrical shock because testing must sometimes be performed where exposed high voltage is present An electrical shock causing 10 milliamps of current to pass through the heart will stop most human heartbeats Voltage as low as 35 volts dc or ac rms should be considered dangerous and hazardous since it can produce a lethal current under certain conditions Higher voltages are even more dangerous Your normal work habits should include all accepted practices to prevent contact with exposed high voltage and to steer current away from your heart in case of accidental contact with a high voltage Observe the following safety precautions 1 There is little danger of electrical shock from the dc output of this power supply However there are several other possible test conditions using this power supply that can create a high voltage shock hazard a If the equipment under test is the hot chassis type a serious shock hazard exists unless the equipment is unplugged just turning off the equipment does not remove the hazard or an isolation transformer is used b If the equipment under test is powered up and that equipment uses high voltage in any of its circuits the power supply outputs may be floa
10. IPMENT PRECAUTIONS Avoid using the power supply in ambient temperatures above 40 C Always allow sufficient air space around the heat sink at the rear of the power supply for effective radiation to prevent internal heat build up Although the power supply is protected against reverse polarity damage the circuit being powered may not include such protection Always carefully observe polarity incorrect polarity may damage the equipment under test 10 Do not exceed the voltage rating of the circuit being powered Most transistors and integrated circuits will not withstand voltage of 35 volts There is no need to worry about voltage spikes or overshoot damaging the equipment under test The voltage between the output terminals of the power supply never exceeds the preset value as the POWER switch is turned on or off HOOK UP 1 2 Turn off the power supply and the equipment to be powered during hook up Connect the positive polarity of the device being powered to the red terminal of the power supply Connect the negative polarity of the device being powered to the black terminal of the power supply Fig 3 illustrates the grounding possibilities a If the negative polarity of the equipment or circuit being powered is also the chassis or common it may be grounded to earth by strapping the black terminal to the green terminal as shown in Fig 3A b Similarly the positive polarity can be grounded
11. TAGE OPERATION 1 Before connecting the device to be powered to the power supply determine the maximum safe load current for the device to be powered and set the current limit value see Setting Current Limit procedure in this section 2 Set Fine VOLTAGE control to center and Coarse VOLTAGE control to minimum fully counterclockwise 3 Turn off power supply and connect it to the device to be powered see Hook Up procedure in this section 8 Turn on POWER switch The CV indicator should light 13 Read output voltage and current on meters CV indicator on ra 17498 DC POWER SUPPLY Preset current limiting Adjust to desired voltage Figure 4 Typical Constant Voltage Operation OPERATING INSTRUCTIONS 5 Increase the VOLTAGE setting until the Voltage LED display reads the desired value The FINE control permits easier setting to a specific value 6 7 Note the load current on the Current LED display If the load current exceeds the preset current limit the CV indicator will go off and the CC indicator will light In this case the power supply automatically switches to the constant current mode and further rotation of the VOLTAGE control will not increase the output voltage SETTING CURRENT LIMIT 1 Determine the maximum safe current for the device to be powered Temporarily short the and terminals of the power supply together with a test lead
12. constant current value the CC indicator will go off and the CV indicator will light In this case the power supply automatically switches to the constant voltage mode and further rotation of the CURRENT controls will not increase the output current 15 Read output current on meter 17438 9C POWER SUPPLY Preset x voltage Adjust to limit desired current CC indicator on Figure 6 Typical Constant Current OPERATING INSTRUCTIONS CONSTANT VOLTAGE CONSTANT CURRENT CHARACTERISTIC The working characteristic of this power supply is called a constant voltage constant current automatic crossover type This permits continuous transition from constant current to constant voltage modes in response to the load change The intersection of constant voltage and constant current modes is called the crossover point Fig 7 shows the relationship between this crossover point and the load For example if the load is such that the power supply is operating in the constant voltage mode a regulated output voltage is provided The output voltage remains constant as the load increases up until the point where the preset current limit is reached At that point the output current becomes constant and the output voltage drops in proportion to further increases in load The crossover point is indicated by the front panel LED indicators The crossover point is reached when the CV indicator goes off and the CC indicator comes on Similarly cros
13. l load current or connect an external ammeter in series with the load 19 If the current equalizing resistors are not well matched it is preferable that the voltages be slightly unbalanced to achieve current balance Be sure that the supplies are adequately balanced so that both remain in the CV mode When connected in parallel and operating in the constant current mode the VOLTAGE controls of both supplies should be preset to the same value Then when the load is connected the CURRENT controls of the two supplies should be adjusted for approximately equal current from each unit Be sure that both supplies remain in the CC mode APPLICATIONS GENERAL These model power supplies have a very wide variety of applications in electrical and electronics servicing engineering laboratories manufacturing and testing facilities schools and home hobbies The power supply output is fully adjustable from 0 to 35 volts and 0 to 10 amps This flexibility makes them suitable for most applications requiring a dc power source ELECTRONICS SERVICING Most electronics troubleshooting and repair is performed on a test bench This power supply can provide the dc power source to operate a module or circuit board on the test bench when it is removed from its parent equipment It can be used to power portable battery operated equipment and check the effect of low battery voltage It can power vehicular equipment such as tape players auto sound systems
14. nd return any leads probes connectors and accessories that you are using with the device Customers not on open account must include payment in the form of a money order or credit card For the most current repair charges please visit www bkprecision com and click on service repair Return all merchandise to B amp K Precision Corp with pre paid shipping The flat rate repair charge for Non Warranty Service does not include return shipping Return shipping to locations in North American is included for Warranty Service For overnight shipments and non North American shipping fees please contact B amp K Precision Corp B amp K Precision Corp 22820 Savi Ranch Parkway Yorba Linda CA 92887 www bkprecision com 714 921 9095 Include with the returned instrument your complete return shipping address contact name phone number and description of problem 25 Limited Two Year Warranty B amp K Precision Corp warrants to the original purchaser that its products and the component parts thereof will be free from defects in workmanship and materials for a period of two years from date of purchase B amp K Precision Corp will without charge repair or replace at its option defective product or component parts Returned product must be accompanied by proof of the purchase date in the form of a sales receipt To obtain warranty coverage in the U S A this product must be registered by completing a warranty registration form online at w
15. ne Control 1745A Fine adjustment of current limit or current value Current can be read from RED LED display OUTPUT TERMINALS 9 Terminal Red Positive polarity output terminal 10 GND Terminal Earth and chassis ground 11 Terminal Black Negative polarity output terminal REAR PANEL CONTROLS 12 Fuse 13 Power Cord CONTROLS AND INDICATORS 3 9 4 REAR PANEL CONTROLS 7 Fuse 8 Power Cord BK PREC ION 17498 BCS ACh EURER 9 110 220 Line Voltage Conversion Switch ta Joi J Be BD i Figure 1 Front Panel Controls and Indicators Figure 2 Rear Panel OPERATING INSTRUCTIONS SAFETY PRECAUTIONS Use only a polarized 3 wire ac outlet This assures that the power supply chassis case and ground terminal are connected to a good earth ground and reduces danger from electrical shock There is little danger of electrical shock from the power supply output which produces a maximum of 35 volts dc However there may be great danger of electrical shock if the power supply output is connected to an external high voltage Some equipment being powered may contain high voltage and present a serious hazard Observe caution If the power supply output is floated referenced to a voltage rather than earth ground turn off the power supply and the equipment under test when making connections Never float the power supply to a potential greater than 100 volts peak with respect to earth ground EQU
16. olts on the GREEN VOLTAGE meter 7 Connect the Multimeter to read the DC current between the black and red output jacks using the 10 amp range The red CC indicator should light and the green CV indicator should go off 8 Set the front panel Fine CURRENT control for a reading of 6 000 amps on the Multimeter Adjust lower RED R304 for a front panel meter reading of 6 000 amps on the RED CURRENT meter INSTRUMENT REPAIR SERVICE Because of the specialized skills and test equipment required for instrument repair and calibration many customers prefer to rely upon B K Precision for this service We maintain a network of B K_ Precision authorized service agencies for this purpose To use this service even if the instrument is no longer under warranty follow the instructions given in the WARRANTY SERVICE INSTRUCTIONS section of this manual There is a nominal charge for instruments out of warranty MAINTENANCE GREEN VOLTAGE METER me RED CURRENT METER mm Figure 11 Location of Adjustments 24 Service Information Warranty Service Please return the product in the original packaging with proof of purchase to the address below Clearly state in writing the performance problem and return any leads probes connectors and accessories that you are using with the device Non Warranty Service Return the product in the original packaging to the address below Clearly state in writing the performance problem a
17. peration at the preset value Reverse polarity protection prevents accidental damage to the power supply from improper connection to an external voltage and current limiting protects the equipment being powered as well as the power supply The output is isolated from chassis and earth ground which permits full flexibility of connections When needed the or polarity may be strapped to ground or either polarity may be floated to an external voltage Two supplies may be connected in series as a 0 to 70 volt power source or two supplies may be connected in parallel with suitable balancing resistors for up to twice the output current These power supplies are well suited for a wide variety of electrical and electronics applications including service shops engineering labs production testing school laboratories and home use by hobbyists FEATURES 0 35 VOLTS Continuously variable over 0 to 35 volts with coarse amp fine controls 0 10 AMPS 0 to 10 amps current rated for continuous duty at full output current Coarse and fine current adjust controls LABORATORY QUALITY Excellent regulation low ripple CONSTANT VOLTAGE OR CONSTANT CURRENT Provides regulated dc voltage output or regulated dc current output Crossover is smooth and automatic LED DISPLAYS model 1745A Two large easy to read LED digit displays monitors output voltage and output current and provides good visibility in bright or low light Two C
18. rent limit on one of the supplies the ather mav he cet far maximum OPERATING INSTRUCTIONS Read output current from Output voltage equals sum of both diplays either ammeter both will read identically JC gt IWER SUPPLY Figure 8 Connecting Two Power Supplies in Series 17 OPERATING INSTRUCTIONS Adjust both power supplies to same voltage 17438 DC POWER SUPPLY 7438 DC POWER SUPPLY Output current equals sum of both displays Use load equalizing resistors Figure 9 Connecting Two Power Supplies in Parallel 18 OPERATING INSTRUCTIONS CONNECTING TWO POWER SUPPLIES IN PARALLEL Two power supplies may be connected in parallel to double the maximum load current In this configuration the two supplies will provide two 0 35 volt output at up to 20 amps heavier gauge hook up leads are advisable Current equalizing resistors must be used as shown in Fig 9 However the protective current limiting feature will prevent damage if current is temporarily unbalanced during set up When connected in parallel and operating in the constant voltage mode determine the total load current limit and preset the current limiting for each power supply to half the total load current value Then when the load is connected set the VOLTAGE controls on the two power supplies for equal voltage readings This should also provide approximately equal current from each supply Add the two current readings together for tota
19. riculum may use the power supply for powering equipment and circuits as previously described for all other applications In addition the power supply can be used in the classroom laboratory to conduct experiments in fundamental electronics In learning Ohm s law for example the relationships of resistance current and voltage are easily demonstrated by the use of a power supply Being able to observe both the current and voltage meter simultaneously is a great aid in such experiments 21 BATTERY CHARGING The power supply can be used as a battery charger to restore the charge in rechargeable batteries such as lead acid nickel cadmium and some alkaline types Refer to the battery manufacturer s charging specifications for proper voltage and current settings Charging information is sometimes printed on the batteries Battery charging at least initially requires the constant current mode of operation Before connecting the power supply to the battery preset the VOLTAGE controls to the fully charged terminal voltage specified by the battery manufacturer Turn off the power supply while connecting the battery Observe proper polarity and connect as for constant current operation Adjust the CURRENT control for the maximum charging current specified by the battery manufacturer If the maximum charging current is greater than the power supply s maximum load current set the CURRENT control to maximum The CC indicator will light and
20. semblies and complete units in the production and assembly area or in the quality control area The instrument can be used in incoming inspection as a dc power source for testing purchased components and subassemblies This power supply is particularly well suited for manufacturing applications because of its ease of operation and its continuous duty rating When load current or total power dissipation are among the main characteristics to be measured the total load current and voltage are easily displayed on the LED displays The current limit can be set so that all units which do not meet the load current specification will cause the CC indicator to light and the unit can be rejected APPLICATIONS ELECTRONICS DESIGN LAB The technician or engineer working in an engineering laboratory requires a dc power supply to power breadboard and prototype circuits This power supply is ideal because it monitors output current output voltage limits current to protect the circuit is adjustable over a wide range and has excellent regulation and very low ripple Use of the instrument in an engineering laboratory is very similar to that described for servicing electronics equipment and modules except that lower currents may be prevalent when powering individual circuits The current limiting feature is very valuable in this application because it can protect unproven circuits from damage ELECTRONICS EDUCATION The student in an electronics cur
21. sover from the constant current to the constant voltage mode automatically occurs from a decrease in load A good example of this would be seen when charging a 12 volt battery Initially the open circuit voltage of the power supply may be preset for 13 8 volts A low battery will place a heavy load on the supply and it will operate in the constant current mode which may be adjusted for a 1 amp charging rate As the battery becomes charged and its voltage approaches 13 8 volts its load decreases to the point where it no longer demands the full 1 amp charging rate This is the crossover point where the power supply goes into the constant voltage mode 16 Constant Current Range Output Voltage Output Current Figure 7 Constant Voltage Constant Current Characteristic CONNECTING TWO POWER SUPPLIES IN SERIES Two Model 1743B power supplies may be connected in series to provide a variable 070 volt output In this configuration two 1743B s provide up to 6 amps See Fig 8 for the connection scheme When connected in series the VOLTAGE controls of each power supply exercise control over a 0 35 volt range Add the two LED readings together to determine the total output voltage Or connect an external voltmeter across the load Load current may be monitored from either supply the readings will be identical since they are connected in series Also since the supplies are connected in series it is only necessary to set the cur
22. ted to the potential at the point of connection Remember that high voltage may appear at unexpected points in defective equipment Do not float the power supply output to more than 100 volts peak with respect to chassis or earth ground c If the equipment under test is off and that equipment uses high voltage in any of its circuits under normal operation discharge high voltage capacitors before making connections or tests Some circuits retain high voltage long after the equipment is turned off 2 Use only a polarized 3 wire ac outlet This assures that the power supply chassis case and ground terminal are connected to a good earth ground and reduces danger from electrical shock 3 Don t expose high voltage needlessly Remove housings and covers only when necessary Turn off equipment while making test connections in high voltage circuits Discharge high voltage capacitors after removing power continued on inside back cover TABLE OF CONTENTS Page TEST INSTRUMENT SAFETY inside front cover INTRODUCTION 4 FEATURES 5 SPECIFICATIONS 6 CONTROLS AND INDICATORS 8 OPERATING INSTRUCTIONS 10 Safety Precautions 10 Equipment Precautions
23. the battery will charge at the preset current limit As the battery approaches full charge its terminal voltage will approach that of the power supply output and the charging current will taper off The power supply may automatically switch to CV constant voltage operation When this occurs the power supply will continue to provide a trickle charge MAINTENANCE WARNING The following instructions are for use by qualified personnel only To avoid electrical shock do not perform any servicing other than contained in the operating instructions unless you are qualified to do SO FUSE REPLACEMENT If the fuse blows the CV or CC indicators will not light and the power supply will not operate The fuse should not normally open unless a problem has developed in the unit Try to determine and correct the cause of the blown fuse then replace only with a fuse of the correct rating as listed below The fuse is located on the rear panel see Fig 2 OPERATION FUSE VALUE TYPE 120 V 6A SLOW BLOW 220 230 240 V 3A SLOW BLOW Table 1 Fuse Values 22 LINE VOLTAGE CONVERSION INTERNATIONAL UNITS The primary winding of the power transformer is tapped to permit operation from 120 220 230 or 240 VAC 50 60 Hz line voltage Conversion from one line voltage to another is done by a simple position change of the fuse receptacle underneath the line cord ADJUSTMENTS This unit was accurately adjusted at the factory before shipment Readjus
24. tment is recommended only if repairs have been made in a circuit affecting adjustment accuracy or if you have a reason to believe the unit is out of adjustment However adjustments should be attempted only if a multimeter with an accuracy of 0 5 DCV or better is available B K Precision Model 2703B or equivalent MAINTENANCE CALIBRATION If readjustment is required use the following procedure Locations of the adjustments are shown in Fig 11 1 Set the front panel controls of the Model 1743BA as follows Coarse and Fine VOLTAGE controls fully clockwise Coarse and Fine CURRENT controls fully clockwise Power switch to On 2 Connect the Multimeter to measure the voltage at pin 14 of IC2 with respect to the front panel red output jack Adjust R21 for 5 00 volts on the Multimeter 3 Connect the Multimeter to measure the voltage at pin 8 of IC2 with respect to the front panel red output jack Adjust R64 for 0 10 mV on the Multimeter 4 Connect the Multimeter to measure the DC voltage between the black and red output jacks The voltage should be 35 to 37 volts the green CV indicator should be lit and the red CC indicator should be off 5 Set the front panel Fine VOLTAGE control for a reading of 35 00 volts on the Multimeter Adjust upper GREEN R304 for a front panel meter reading of 35 00 volts on the GREEN VOLTAGE meter 23 6 Set the front panel Coarse VOLTAGE control for a reading of 04 00 to 06 00 v
25. urrent Ranges model 1744A High Low switch selects full output 0 10A or on quarter output 0 2 2A Low range improves current settability and meter resolution LED INDICATORS Act as pilot light and identify mode of operation and metering PRE REGULATOR Limits internal dissipation for higher reliability ISOLATED OUTPUT Either polarity may be floated or grounded OVERLOAD PROTECTION Fully adjustable current limiting from 5 to 100 of maximum output current protects circuit under test and the power supply REVERSE POLARITY PROTECTION Prevents damage to power supply from external voltage of reverse polarity STYLING Modern functional styling Logical convenient layout of controls SPECIFICATIONS OUTPUT VOLTAGE 0 to 35 VDC coarse and fine adjustment OUTPUT CURRENT 0 to 10 A coarse and fine adjustment CONSTANT VOLTAGE OPERATION Voltage Regulation Line 108 132 V Load no load to full load lt 0 2 2 mV lt 0 04 lt 0 04 2 mV Recovery Time lt 100 us typical Ripple Voltage RMS lt l mV Temperature Coefficient 0 to 40 C lt 300 PPM C CONSTANT CURRENT OPERATION Adjustable Current Limits 5 to 100 Current Regulation Line 108 132 V lt 0 4 5 mA Load lt 0 4 5 mA Current Ripple lt 3 mA typical METERING Model 1745A Voltmeter 4 digit Green LED Display Range 0 to 99 99 V Accuracy 0 5 9 digits Ammeter 4 digit Red LED Display Hi Range 0 to 9 999 A
26. ww bkprecision com within fifteen 15 days of purchase Exclusions This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs The warranty is void if the serial number is altered defaced or removed B amp K Precision Corp shall not be liable for any consequential damages including without limitation damages resulting from loss of use Some states do not allow limitations of incidental or consequential damages So the above limitation or exclusion may not apply to you This warranty gives you specific rights and you may have other rights which vary from state to state B amp K Precision Corp 22820 Savi Ranch Parkway Yorba Linda CA 92887 www bkprecision com 714 921 9095 Model Number Date Purchased 26 TEST INSTRUMENT SAFETY continued from inside front cover If possible familiarize yourself with the equipment being tested and the location of its high voltage points However remember that high voltage may appear at unexpected points in defective equipment Use an insulated floor material or a large insulated floor mat to stand on and an insulated work surface on which to place equipment and make certain such surfaces are not damp or wet When testing ac powered equipment the ac line voltage is usually present on some power input circuits such as the on off switch fuses power transformer etc any time the equipment is connected to
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