Global Specialties 1310 User Manual

DC Power Supply
1310
Instruction Manual
1310
DC POWER SUPPLY
Operation Manual
M-00367 EDITION : 1 ( JAN., 2012 )
80-01-0538 S/90
GLOBAL SPECIALTIES
22820 Savi Ranch Parkway Yorba Linda, CA 92887
TEL.: (800) 572-1028 FAX.: (215) 830-7370
TABLE OF CONTENTS
SECTION DESCRIPTION PAGE NO.
1 INTRODUCTION 1
2 SPECIFICATIONS 2
3 OPERATING INSTRUCTIONS 4
4 CIRCUIT DESCRIPTION 11
5 SERVICE & 13
WARRANTY INFORMATION
6 MAINTENANCE & CALIBRATION 15
7 PART LIST & SCHEMATICS 19

ABOUT GLOBAL SP E C I A LTIES
Thank-you for selecting a GLOBAL SPECIALTIES product. You won’t be disappointed ! Because we’ve never strayed from our original founders’ simple ideal, lower the high cost of electronic design and testing. Over the years, we’ve offered you electronic testing and prottyping equipment that was engineered for the processinal, but economically priced. The “best for less”, never compromising quality in order to give you, our customer, a real value.
We accomplish our goal by cutting the industry giants down to size. Most test equipment comes with excess features that you don’t want, but have to pay for anyway. We eliminate these high cost features, lower the price, but not the performance. The result is smarter tools for the value minded user.
We pioneered the breadboarding industry allowing you to create circuits as fast as you can think. Our breadboards are constructed to last. We use high impact plastic and nickel silver contacts, plus “Made in U.S.A.” quality and an unconditional lifetime guarantee. Our logic probes offer speeds and storage capabilities only equaled by the fastest oscilloscopes. When it comes to frequency counters we offer you far more performance for far less money. Handheld or benchtop, frequency counters or universal counter-timers, whatever you application you can count on us. Our complete family of bench-top instruments offers you features and performance unequaled, dollar for dollar.
In our continual strive for the “best for less” we never lose sight of the future. We are always searching for ways to improve our existing products and design new products using the latest technology. We do this by asking you, our customers, what your needs are, and what your likes and dislikes are. Feel free to contact us by phone, mail or fax with your comments. Tell us how we can put Global to work for you.

PCB Components 1310-PS-MAIN PCB
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Ref Designator Value
=======================================================================
DIODES
D5 1N751 ( 5.1V ) D17 1N4148 D18 1N4148 D25 1N4148 D26 1N4148 D1 1N4007 D2 1N4007 D3 1N4007 D4 1N4007 D10 1N4007 D11 1N4007 D13 1N4007 D14 1N4007 D15 1N4007 D16 1N4007 D19 1N4007 D20 1N4007 D21 1N4007 D22 1N4007 D23 1N4007 D24 1N4007 D27 1N4007 D28 1N4007 D6 1N5408 D7 1N5408 D8 1N5408 D9 1N5408
In closing, we at GLOBAL SPECIALTIES would like to express our appreciation to our many loyal customers. We pledge to not rest on our laurels nor will we forget our main objective, to supply the “best for less”.
PCB Components 1310 DISPLAY PC B
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Ref Designator Value
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FNDs
FND1 RED FND COMM. ANNODE. FND2 RED FND COMM. ANNODE. FND3 RED FND COMM. ANNODE.
21
PCB Components 1310-PS-MAIN PCB
=======================================================================
Ref Designator Value
=======================================================================
CAPACITORS
C1 22µF, 50V, ELE C2 22µF, 50V, ELE C3 1000µF, 35V, ELE C4 0.1µF, 100V, MP C5 22µF, 16V, ELE C6 0.1µF, 100V, MP C7 22µF, 16V, ELE C8 0.1µF, 100V, MP C9 4700µF, 16V, ELE C10 0.1µF, 100V, MP C11 22µF, 16V, ELE C12 22µF, 16V, ELE C13 0.1µF, 100V, MP C14 2200µF, 35V, ELE C15 0.1µF, 100V, MP C16 22µF, 16V, ELE C17 22µF, 50V, ELE C18 0.1µF, 100V, MP C19 2200µF, 35V, ELE C20 0.1µF, 100V, MP C21 0.1µF, 100V, MP C22 22µF, 50V, ELE C23 0.1µF, 100V, MP C24 0.22µF, 100V, MP C25 0.47µF, 100V, MP C26 0.1µF, 100V, MP C27 0.1µF, 100V, MP C28 100pF, 500V, CD C29 0.1µF, 100V, MP C30 0.022µF, 400V, VDC, MP AX
SECTION - 1
INTRODUCTION
POWER SUPPLY : MODEL1310
The 1310 Power Supply is a versatile triple-output unit which can be used in both digital and analog circuit applications. It consists of three independent power supplies: a foxed 5 volt supply rated at
1.0 amps maximum, and two variable 1.3 to 20 volt supplies each rated at 250 milliamps maximum. The three digit display allows the voltage of the variable supplies to be quickly and accurately set, and current flow can be monitored with 1 milliamp resolution.
All three supplies are completely isolated from each other, and from earth ground. A circuit or piece of equipment connected to any one of the supplies may be floated to DC level different from the other two supplies. In addition, any two - or all three - supplies may be connected to the chassis and earth ground is provided. And, of course, each supply is protected against short circuit and thermal overloads.
The 1310 is an excellent general purpose power supply for engineering lab applications, bread-boarding, and prototyping. The triple-output voltages make it ideal for working with all disciplines, from microcomputer components to op-amps. Priced economically, the 1310 is the perfect choice for production lines, service shops, hobbyists, and whenever a compact, reliable DC power supply is needed.
TRANSISTORS
Q1 2N3906 Q2 2N3904 Q3 2N3904
ICs
U1 LM317 U2 LM354 U3 LM317 U4 78S05 U5 7107
120
SECTION - 2
SPECIFICATIONS
POWER REQUIREMENTS : 108 to 132V AC, 50 to 60Hz ( 215 to
250VAC, 50 to 60Hz model available )
OUTPUTS ( All floating via Transformer Isolation ) :
5V Power Supply :
Voltage : 5V DC ( ±0.2V ) fixed.
Current : 1.0A Maximum.
Regulation :
Line : 0.2%.
Load : 1.0%.
Ripple : 0.1% 5mV Maximum
A Power Supply :
Voltage : 1.3 to 20V DC (continuously variable)
Current : 250mA Maximum.
Regulation :
Line : 0.1%.
Load : 0.2%.
Ripple : 10mV Maximum.
B Power Supply :
Voltage : 1.3 to 20V DC (continuously variable)
Current : 250mA Maximum.
Regulation :
Line : 0.1%.
Load : 0.2%.
Ripple : 10mV Maximum.
CONTROLS : Power ON/OFF, variable voltage adjust
(A), variable voltage adjust (B), meter select Volts, Amps, meter selectA/B.
2
SECTION - 7
PART LIST & SCHEMATICS
PCB Components 1310-PS-MAIN PCB
=======================================================================
Ref Designator Value
=======================================================================
RESISTORS
R1 1K, ¼W, 1%, MFR R2 1E, ½W, 1%, MFR R3 1E, ½W, 1%, MFR R4 1K, ¼W, 1%, MFR R5 1K, ¼W, 1%, MFR R6 100E, ½W, 1%, MFR R7 300E, ¼W, 1%, MFR R8 1K, ¼W, 1%, MFR R9 1E, ½W, 1%, MFR R9a 1E, ½W, 1%, MFR R11 150E, ¼W, 1%, MFR R13 82K, ¼W, 1%, MFR R14 1K, ¼W, 1%, MFR R16 82E, ¼W, 1%, MFR R18 270K, ¼W, 1%, MFR R19 220E, ¼W, 1%, MFR R21 1K, ¼W, 1%, MFR R22 1E, ½W, 1%, MFR R22a 1E, ½W, 1%, MFR R23 82E, ¼W, 1%, MFR R24 220E, ¼W, 1%, MFR R26 1K, ¼W, 1%, MFR R27 82K, ¼W, 1%, MFR R31 270K, ¼W, 1%, MFR R32 220E, ¼W, 1%, MFR R34 1K, ¼W, 1%, MFR R56 47K, ¼W, 1%, MFR R57 100K, ¼W, 1%, MFR R59 22K, ¼W, 1%, MFR R60 100K, ¼W, 1%, MFR R61 1K, ¼W, 1%, MFR R62 1K, ¼W, 1%, MFR
PRESETS
R12 100E ( H ) Preset Pot R20 100E ( H ) Preset Pot R25 100E ( H ) Preset Pot R33 100E ( H ) Preset Pot R58 1K ( H ) Preset Pot R15 50K ( H ) Preset Pot R28 50K ( H ) Preset Pot VR1 1K Carbon Lin Pot Metal Shaft VR2 1K Carbon Lin Pot Metal Shaft
19
The board can now be removed by lifting the PC board, front panel, and rear panel straight upward from the case as a unit. If desired, the connectors may be unplugged from the PC board to facilitate service; note the position of each connector and mark them to ensure proper reassembly.
6.4 CASE REASSEMBLY :
The reassemble the case, refer to figure 7 ( Case Assembly ) and proceed as follows:
1. Remove all connections to the binding posts and unplug the 1310 from the AC supply. Ensure that both upper and lower case halves are clean and free of debris.
2. If the PC board has been removed from the upper case half, replace it as follows :
a) If the front and rear panels have been disconnected from the
PC board: slide the front panel and rear panels into the appropriate grooves ( the front of the case is the beveled side ) in the upper half of the case, while allowing the main PC board to drop into the case
b) If the front and rear panels have been disconnected from the
PC board: set the PC board into the upper case half, observing orientation ( i.e., while facing the front [ beveled side ] of the upper case half, the heat sinkds on the PC board should be to the right ). Install the front and rear panels into their appropriate grooves, noting that they should be "upside-down", and plug the panel connectors into the main PC board.
c) Loosely install the four hex stand offs that hold the main PC
board to the upper case half.
d) Install the self-tapping screw in the center of the PC board,
being careful not to over tighten.
e) Now tighten the four hex stand offs holding the main PC board.
3. Gently slide the lower case half straight down into position atop the upper case half, making sure that the beveled sides face the front and that the front and rear panels are fitting properly in the case panel grooves.
4. Position the flip-up leg and the foot assemblies. The flip-up leg assembly should be to the front, and the leg should fold rearward.
5. Replace the Philips-head screw in each foot assembly, taking care not to over-tighten.
6. Replace the stick-on rubber feet.
7. Return the 1310 to the upright position.
MONITORS : 3 digit LED display. Voltage or current
display selectd by V/A switch. A or B supply display by A / B switch. Display accuracy ±0.5%, ±1 digit. Resolution of 1mA when displaying current,0.1V when displaying voltage LED indicates overload on 5V supply
SHORT CIRCUIT : All supplies current limited ( external PROTECTION short circuit will not damage power
supplies ).
LINE CORD : 3 Wire with American Plug.
DIMENSION ( H x W x D ) : 70mm x 265mm x 322mm.
WEIGHT : 2.585 Kgs.
18
3
SECTION - 3
OPERATING INSTRUCTION
3.1 LOCATION & DESCRIPTION OF OPERATING CONTROLS :
The properly use the full capabilities of the 1310, it is highly recommended that the user become familiar with the instrument's controls and their function ( See figure 1 ).
1 - Power ON / OFF Switch :
Rocker Switch. The digital display will light to indicate power is on.
27) Set the VOLT / AMP ME TER S WIT CH t o the A positi on an d ad jus t tri mpo t R25 until the 1310 display reads 250.
28) Set the A / B METER SWITCH to the B position and adjust trimpot R until the display once again reads 250.
29) Turn power off, disconnect all equipment, and reassemble the 1310 as outlined under the CASE REASSEMBLY section of this manual.
6.3 CASE DISASSEMBLY :
12
2 - A Adjust Control :
Adjust the output voltage of a supply from 1.3 to 20 volts. Clockwise rotation increases the voltage.
3 - B Adjust Control :
Adjust the output voltage of the B supply from 1.3 to 20 volts. Clockwise rotation increases the vltage.
4 - A/B Meter Switch :
When switched to A, the digital display will show the output, either voltage or current (as selected by the VOLT / AMP METER Switch,q.v.), of the A Supply. Similarly, when switched to B, the output of the B supply will be displayed.
5 - Volt / Amp Meter Switch :
When switched to V, the display will indicate the voltage output of the supply selected by the A/B Meter Swith. When switched to A, the current output of the selected supply will be displayed.
6 - Display :
Three digit LED display shows the output current or voltage of the A or B supply, depending on the settings of the Volt / Amp Meter switch and A/B Meter Switch.
4
Figure 7 : Case Assembly
Should access to the inside of the unit be required, refer to figure 7 and proceed as follows:
1. Disconnect all cables and equipment from the front panel binding posts of the 1310.
2. Disconnect the power cord from the AC outlet.
3. Turn the 1310 upside-down on a soft or padded surface.
4. Remove the stick-on rubber feet from the foot assemblies. Place them aside, non-sticky side down.
5. Remove the Philips-head screw from each of the four foot asemblies.
6. Remove the foot assemblies and the flip-up leg.
7. Gently slide the lower half of the case straight upward until it is clear of the unit. The PC board will now be visible.
8. If necessary, the PC board can be taken out of the upper case half in the following manner :
a) Remove the self-tapping screw from the center of the PC board.
b) Remove the four hex standoffs that hold the PC board to the
upper case half.
17
4 ) Adjust trimpot R
5 ) Set VOLT / AMP METER SWITCH of the 3310 to the V ( Volt ) position.
6 ) Set the A / B METER SWITCH of the 1310 to the A position.
7 ) Connect the digital multimeter to the A supply binding posts, with the
positive lead on the red binding post and the negative lead on the black binding post.
8 ) Set the A ADJUST CONTROL for a reading of 20.0 volts on the digital
multimeter.
9 ) Adjust trimpot R
10) Set the A / B METER SWITCH of the 1310 ot the B position.
11) Connect the digital multimeter to the B supply binding posts, with the positive lead on the red binding post and the negative lead on the black binding post.
12) Set the B ADJUST CONTROL for a reading of 20.0 volts on the digital multimeter.
13) Adjust trimpot R
14) Disconnect the digital multimeter from the binding posts and set the VOLT / AMP METER SWITCH to the A position.
15) Adjust trimpot R
16) Set the A / B METER SWITCH to the A position.
17) Adjust trimpot R
18) Set the VOLT / AMP METER SWITCH to the V position, and turn the 1310 off.
19) Connect a jumper from the positive ( Red ) binding post of the A supply to the negative ( Black ) binding post of the B supply.
20) Set the A and B ADJUST CONTROLs to their fully counterclockwise position.
21) Connect one end of an 80 Ohm resistor to the positive binding post of the B supply.
22) Connect the other end of the 80 Ohm resistor to the position lead of the digital multimeter.
23) Connect the negative lead of the digital multimeter to the negative binding post of the A supply.
24) Set the digital multimeter to measure and display current.
25) Turn the 1310 on and, while monitoring the A supply voltage on the 1310 display, set the A supply for a 10 volt output.
26) Increase the output of the B supply until the digital multimeter reads 250 milliamps.
to obtain a reading of 100.0 millivolts.
58'
to obtain a reading of 20.0 volts on the 1310 display.
33'
to obtain a reading of 20.0 on the 1310 display.
20'
to obtain a reading of 000 on the display.
15'
to once agai n obtain a reading of 000 on the display.
28'
16
7 - Flip-up Leg :
Easily raised or folded, this will elevate the front of the power supply approximately 1 inche for better visibility.
8 - Ground terminal :
Binding post connected to the chassis and to earth ground through the third wire of the AC power line cord.
9 - B Terminals :
Output terminals for variable supply B. The red terminal is positive ( + ); the black terminals is negative ( - ).
10 - A Terminals :
Output terminals for variable supply A. The Red terminal is positive ( + ), the black terminals is negative ( - ).
11 - 5 Volt Terminals :
Output terminals for the 5 volt DC supply. The Red terminal is positive ( + ), the black terminal is negative ( - ).
12 - Overload Indicator :
LED lights when 5 volt supply current exceeds approximately 1 amp.
3.2 INITIAL INSPECTION and CHECKOUT
Plug the line cord into a suitable 3-wire AC outlet. Note : if a 2-wire to 5 wire adapter must be used. be sure the groundwire or tab of the adapter is attached to a good earth ground. This promotes safe operation by keeping the case, chassis, and earth ground binding post at true earth potantial.
With no load connected, turn on the power supply by pressing the POWER switch; display will light to indicate the power is applied. Turn both the A & B voltage controls fully counter-clockwise to their minimum settings. Set the A / B meter switch to the A position. Set the V / A meter switch to the V setting. Slowly increase the A supply output voltage by rotating the A supply voltage control clockwise.
The display should show an increase from 1.3 volts ( or less ) at the minimum setting to 20.0 volts ( or more ) at the maximum setting. Check the variable supply B by setting the A / B meter switch to B and rotating the B supply voltage control clockwise. Again the display should show an increase from 1.3 volts to 20.0 volts.
The fixed 5 volt supply may be checked by attaching an external voltmeter to the 5 V output terminals. The voltmeter should read between 4.8 and 5.2 volts.
5
3.3 PRECAUTIONS :
The Power supply is ideally suited to virtually any type of IC breadboarding from TTL, CMOS, and ECL to op-amps, audio and video amps, phase-locked loops, and microprocessor circuitry. However, certain normal breadboarding precautions should be taken to avoid ground loops and inadvertent loading. Observance of correct load polarity is also important, since most ICs may be damaged by improper power supply connections.
3.4 Polarity :
Observe proper polarity when connecting the power supplies to the load, especially if the load is polarity sensitive and does not have reverse polarity protection.
3.5 Ground Loops :
A ground loop is voltage drop on a ground bus caused by a power stage output entering the ground bus some distance away from the power supply ground binding post.
This small voltage drop, though only millivolts or microvolts, is part of the output load. If a preamplifier input or circuit ground is connected to a portion of this ground bus, feedback and oscillation may occur. To prevent this, all output stages should be positioned as close as possible to the ground terminal, with preamps being father awat. Many audio ICs have separate input and output grounds to prevent ground loops.
Even though the power supplies are tightly regulated, a short length of power bus can prevent enough inductance to cause linear IC oscillation at high frequencies. For this reason, effective bypass capacitors are needed to bypass the power busses as possible to the power supply pins of the IC. Disc ceramics ( 0.1µF ) work well and should be placed across as may ICs as possible. Do not use electrolytic or paper capacitors because they have high inductances and cease to act as bypasses above one or two megahertz. Bypassing is required with digital ICs also; problems such as inability to reset or to clear and false triggering can occur if bypass capacitors are not installed.
3.6 Ventillation :
The heat generated in the power supply is convected through the ventilation slots in the bottom and top of the case. For best ventilation, always leave a few inches of space around the unit. Never allow any object to block the ventilation holes or reduce the clearance provided by the feet on the bottom of the case.
SECTION - 6
MAINTENANCE AND CALIBRATION
6.1 FUSE REPLACEMENT :
The 1310 uses a type 3AG, ½A ( ¼A for 230 volt units ), 250 volt slow acting power fuse. If replacement becomes necessary, follow this procedure :
a. Disconnect all cables and connections to the 1310.
b. Unplug the power cord at the AC outlet.
c. Unscrew the fuse holder cap from teh fuse holder ( found on the rear
panel ).
d. Remove the defective fuse and replace it with one of an identical type
and rating.
e. Reinstall the fuse holder cap, making sure that it is tightened securely.
If any additional maintenance or repair is require, it is recommended that the unit be returned to Global Specialties for service ( see FACTORY SERVICE and REPAIR ).
6.2 CALIBRATION :
The 1310 has been designed to provide years of trouble-free service, but to maintain the accuracy of the digital display the unit should be returned to the factory on an annual basis, or whenever the accuracy of the display is in question. If this is not possible or practical, the following calibration can be performed in the field :
6.2.1 Equipment Required :
( 1 ) Digital multimeter, 3½ digits or greater, with an accuracy of 0.25% or
better.
( 2 ) 80 Ohms, 5 Watt ( or greater ) resistor.
WA RNIN G : During the course of this procedure, power will be applied
and potentially lethal voltages will be present. Exercise extreme caution during all phases of the calibration, and particularly when adjustments are being made.
6.2.2 Procedure :
1 ) Open the case of the 3310, following the procedure outlined under the
CASE DISASSEMBLY section of this manual.
2 ) Apply power to the 3310, allowing at least 15 minutes for warm-up.
3 ) Connect the digital multimeter to pins 35 and 36 of U5' with the positive
lead on pin 35 and the negative lead on pin 35.
6
15
Specifications subject to change without notice.
!!Copyright 1994, INTERPLEX ELECTRONICS, INC, Unit No.2, Highland Industrial Centre 1486, Highland Avenue, Cheshire CT 06410, U.S.A. !!and TM trademarks are the property of INTERPLEX ELECTRONICS, INC, Unit No.2, Highland Industrial Centre 1486, Highland Avenue, Cheshire CT 06410, U.S.A.
CASE DISASSEMBLY AND ASSEMBLY
WARNING
Potentially lethal AC power is present whenever the line cord is plugged into the AC outlet, even when the power switch is OFF. Always disconnect the power cord when opening the case. Avoid touching the fuse post on the inside of the unit.
Should access to the inside of the unit be required, proceed a follows:
1. Remove the line cord from the AC outlet before disassembly.
2. To disassemble the case, remove the screws that secure the cover to the chassis and lift the cover off.
3. To reassemble the case, place the cover on the chassis, line up the screw holes, and replace the screws.
MAINTENANCE AND RECALIBRATION
3.7 OPERATION :
Proper operation of most circuitry depends on correct voltage. It is recommended that the variable supplies be set to the required voltage levels with their loads disconnected. When the desired voltage is set ( using the A or B voltage control ), turn the AC power off, connect each load to the proper supply, and turn the AC power on.
Output voltage may be continuously monitored by setting the V / A meter switch to the V position, setting the A / B switch to the desired supply position, and reading the output voltage on the digital display, Output current may be read by simply changing the V / A switch from the V to the A position.
3.8 GROUNDING
All three power supplies are isolated and may be operated without any reference to earth ground. If an earth reference is required, one terminal ( either + or - ) from any one, two, or all three supplies may be connected to the earth ground binding post.
3.9 CURRENT LIMITING :
Each power supply is protected against output short circuit. If any output is short-circuited, the voltage drops to zero and the current is limited to a safe value.
3.10 COMBINING POWER SUPPLY :
Each of the three supplies may be used independently, or in a combination of any two or all three. These combinations, outlined in figure 2 and described below, can yield increased voltage ranges, increased current capability, or a split plus and minus supply such as frequently used in analog circuitry.
ADJUSTMENTS
All circutry is factory-calibrated. No user adjustments are required.
FUSE REPLACEMENT
Remove the line cord from the AC outlet before changing fuses. Using a screwdriver, remove the fuse holder cap. Replace the fuse with another fuse of identical type and current rating. Replace the fuse holder cap.
14
Power Supply Connection Voltage Range Max. Current
5V -- 5 Volts 1.0 Amps
A ( variable ) -- 1.3 to 20Volts 250 Milliamps
B ( variable ) -- 1.3 to 20Volts 250 Milliamps
A + B Parallel 1.3 to 20Volts 500 Milliamps
A + B Series 2.6 to 40Volts 250 Milliamps
5V + A or B Series 6.3 to 25Volts 250 Milliamps
5V + A + B Series 7.6 to 20Volts 250 Milliamps
A + B Split Supply +1.3 to +20Volts, 250 Milliamps
-1.3 to -20V
Figure 2 : Power Supply Interconnections
7
3.11 Series Connection :
The output of the variable supplies may be connected in seriess to provide a variable 2.6 to 40 Volt output at currents of up to 250 milliamps ( see figure 3 ). The total voltage may be determined by adding the separate voltage readings for each variable supply. Load current may be monitored from the output of either variable supply.
SECTION - 5
SERVICE AND WARRANTY INFORMATION
FACTORY SERVICE AND REPAIR
Global Specialties will service and repair this instrument free of charge for a period of one full year, subject to the warranty conditions stated below.
To obtain a return merchandise authorisation (RMA) required for all returns, phone our Customer Service Department for a RMA and all shipping instructions:
GLOBAL SPECIALTIES
22820 Savi Ranch Parkway Yorba Linda, CA 92887 TEL.: (800) 572-1028 FAX.: (215) 830-7370
WARRANTY
Figure 3 : 2.6 to 40 Volt Series Connection
NOTE : When the variable supplies are connected in series, each
supply should be set to one-half the desired combined voltage. This will assure even power distribution between the supplies. For example, to achieve an output voltage of 35 volts, set each variable supply to 17.5 volts.
The highest output voltage may be realized by connecting the two variable supplies in series with the fixed 5V supply, giving a range of 7.6 to 45 volts with a maximum current of 250 milliamps ( see figure 4 ). Again, the total voltage may be determined by adding the individual output voltage, and the current may be monitored from the output of either variable supply.
Global Specialties warrants this device to be free from defective material or workmanship for a period of one full year from the date of original purchase.
Global Specialties under this warranty is limited to repairing the defective device when returned to the factory, shipping charges prepaid, within one full year from the date of original purchase. Units returned to Global Specialities that have been subject to abuse, misuse damage or accident, or have been connected, installed or adjusted contrary to the instructions furnished by Global Specialities, or that have been repaired by unauthorized persons will not be covered by this warranty.
Global Specialities reserves the right to discontinue models, change specifications price or design of this device at any time without incurring any obligation whatsoever.
The purchaser agrees to assume all liabilities for any damages and/or bodily injury which may result from the his employees or agents.
This warranty is in lieu of all other representations or warranties expressed or implied and no agent or representative of Global Specialties is authorized to assume any other obligation in connection with the sale and purchase o f this device.
use or misuse of this device by the purchaser,
Figure 4 : 7.6 to 45 Volt Series conne
8
ction
13
DIGITAL DI SPLAY :
Display of voltage and current is accomplished by U digit A / D con vert er LE D dis play driver. Power for this device is supplied
an ICL7107 3½
5'
by a separate transformer, T1. The center-tapped output of this transformer is full-wave rectified by diodes D1 through D4 and filtered by capacitors C1 through C4. The +5V supply, used only by U created by U further filtered by capacitors C5 and C7. The -5A supply, also used only by U
is produced by zener diode D
5'
a 7805 three-terminal 5 volt regulator, whose output is
1'
with filter capacitors C6 and C7.
5'
5'
The A / D converter is calibrated for a full scale range of 200mV. The current and voltage outputs of the variable supplies are therefore scaled to accommodate this range, and the signals are routed to the A / D converter through switches S2 ( the A / B supply switch ) and S3 (the V / A select switch). The yields a display of 000 - 250 to represent a current flow from the variable supplies of 0 to 250 milliamps, and a display of 013 - 200 to represent an output voltage of 1.3 to 20.0 volts. When in the voltage range, the proper decimal point on the LED display is illuminated by the action of switch S3 to correctly indicate the voltage.
3.12 SPLIT SUPPLY :
A split supply may be arranged by connecting the positive ( + ) terminal of one supply to the negative ( - ) terminal of any other supply ( see figure 5 ). These connected terminals are then used as circuit ground ( also called circuit common ). This arrangement
is
is often used with op-amps which required a +V and -V supply.
Figure 5 : Split Supply "Connection
CAUTION : The power supplies should not be connected in any
manner which causes electron current to flow out of a positive ( + ) terminal or into a negative ( - ) terminal. This would be a series subtraction configuration, and could damage the 1310.
12
3.13 PARALLEL CONNECTION :
The variable supplies may be connected in parallel to increase the available load current, giving an output of 1.3 to 20 volts at up to 500 milliamps. However, current-equalizing resistors must be used ( see figure 6 )
Figure 6 : Parallel Connection
9
For best results, set the variable supplies to the desired voltage before any connections are made. If the current equalizing resistors are not well matched, current balance may be achieved by slightly unbalancing the supplies while measuring the current output of each supply. The voltage applied to the load must be moitored with an external meter, since the current balancing resistors will introduce a voltage drop, and will also adversely affect voltage regulation. For these reasons, it is best to keep the value of the current balancing resistors as low as possible. However, the lower value, the more difficult it will be to balance the supplies. Each circuit powered this way will required its own tradeoffs.
SECTION - 4
CIRCUIT DESCRIPTION
For the following circuit description, refer to the schematic.
5V SUPPLY :
Diodes D6 through D9 make up a full-wave bridge which rectifies the 10 volt AC secondary winding of transformer T2 used for the 5 volt DC supply. This rectified output is filtered by capacitors C9 and C serves as the input to U The output of U2 is fixed at 5 volts by R6 and R further filtering the output and improveing transient load response. diode D such as might occur if the output is shorted. Diode D
protects U2 from destructive current flow into its adjust pin,
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additional protection for U2 from the inadvertent application of voltage
an LM317 adjustable three-terminal regulator.
2’
7’
with C
11’ C12’
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to the 5V terminals.
Resistors R2 and R3 are used to sense current flow into, and therefore out of, the regulator. When currents exceed approximately 1 amp, the voltage drop across these resistors will be sufficient to turn on transistor Q
which in turn lights D
1’
ultimately limited by U2 to a safe level.
the OVERLOAD LED. Current flow is
12’
VARIABLE SUPPLIES :
Since the operation of both variable supplies is identical, the following discussion will deal only with the B variable supply.
The transformer secondary is rectified by the full-wave bridge comprising D C
. This serves as the unregulated input to U
15’
three-terminal regulator. The output of U3 is set by fixed resistor R and variable resistor R and C transient load response. Diode D
accomplish additional filtering for the output, and improve the
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current flow that would occur into its adjust pin if the output becomes shorted, and diode D output being raised above its input voltage.
through D
13
and is filtered by capacitors C
16’
the B ADJUST control. Capacitors C
17
protects the regulator from the
19
protects the regulator from the condition of its
20
an LM317 adjustable
3’
and
10
and C
13
provides
and
14
16
16’ C17’
10
Resistors R9 and R a voltage drop that ultimetaly is used for the current reading on the
sense current flow through the supply, creating
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digital display. As there is a constant current flowing in the supply circuitry even when there is no load attached, it is necessary to subtract this so that the display shows true load current. This is done by the constant current sink made up of transistor Q R
and diodes D
15'
resulting voltage to supply a 0.1mV / mA signal to display circuitry. Similarly, resistors R voltage to procedure a 1mV / V signal for the display circuitry.
and D
17
18' R19'
Resistors R8' R
18'
and R
20
resistors R
2'
and R
11'
13' R14'
12
and
scale this
scale the final supply output
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