B&K Precision 1762 User Manual
INSTRUCTION
MANUAL
MODELS: 1760A, 1761, 1762
Triple Output
DC POWER SUPPLY
With Dual 4-Digit LED Displays
2
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 cont act 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. H owever, there are severa l other possible
test con ditions usin g 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 floated 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)
3
Instruction Manual
For Models
1760A, 1761, 1762
Triple Output DC Power Supplies
With Dual 4-Digit LED Displays
22820 Savi Ranch Parkway
Yorba Linda, CA 92887
www.bkprecision.com
4
TABLE OF CONTENTS
page
Page
TEST INSTRUM E NT S AF ETY ------------- inside front cover
INTRODUCTION ------------------------------------------------ 5
FEATURES ------------------------------------------------------- 7
SPECIFICATIONS ---------------------------------------------- 8
CONTROLS AND INDICATORS ---------------------------- 10
General Controls and Indicators ------------------------------- 10
4-6.5 V Supply Controls and Indicators ---------------------- 10
“A” Supply Controls and Indicators--------------------------- 12
“B” Supply Controls and Indicators --------------------------- 12
Rear Panel Controls --------------------------------------------- 13
OPERATIN G IN S TRU CTI ONS ------------------------------- 14
Safety Precautions ----------------------------------------------- 14
Equipment Precautions ----------------------------------------- 14
Independent Use of “A” or “B” Supply ----------------------- 14
Hook-up ---------------------------------------------------------- 15
Typical Constant Voltage Operation -------------------------- 18
Setting Current Limit ------------------------------------------- 19
Typical Constant Cu r r ent Operat i on -------------------------- 20
Constant Voltage/Current Characteristic --------------------- 21
Series Tracking Operation -------------------------------------- 22
Parallel Tracking Operation ------------------------------------ 26
4-6.5 V Po wer Sup ply O peration ------------------------------ 29
APPLICATION ---------------------------------------------------- 33
General -------------------------------------------------------------- 33
Electronics Servicing ---------------------------------------------- 33
Electronics Manufacturing ---------------------------------------- 33
Electronics Design Lab -------------------------------------------- 34
Electronics Education --------------------------------------------- 34
Battery Charging --------------------------------------------------- 34
Split Supply --------------------------------------------------------- 34
MAINTENANCE -------------------------------------------------- 41
Fuse Replacement -------------------------------------------------- 41
Line Voltage Conversion ------------------------------------------ 41
Adjustments -------------------------------------------------------- 42
“A” Supply and “A” Metering Adjustments -------------------- 42
4-6.5 V Supply and 6.5 V Metering Adjustments -------------- 44
“B” Supply and Metering Adjustments -------------------------- 44
“B” Series Tracking Adjustment --------------------------------- 45
Instrument Repair Service ---------------------------------------- 45
WARRANTY SERVICE INSTRUCTIONS -------------------- 46
LIMITED TWO-YEAR WARR ANT Y -------------------------- 47
5
INTRODUCTION
These B+K Precision Triple Output DC Power Supplies are high
The two “main” volt supplies can be operated independently or in
tracks from 5% to 100% of the voltage of the “A” Supply. Maximum
. In the parallel tracking mode, the two supplies are
Both “main” volt supplies 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
In constant voltage applications, a current limit may be preset. When
In constant current ap plicatio ns, the maximu m voltage ma y
limits the current output to a maximum of 5 amps. An
permits full flexibility of connections. When needed, the (+)
itive, or one positive, one
negative, and a common. All of these configurations can be
used with either matching (tracking) or differing
quality, general purpose DC power sources. They provide two “main”
supplies and a “third” auxiliary output with a 4-6.5V (2-6.5V for
models 1761 & 1762) DC output. The “main” V su ppli es are ad ju stabl e
with both coarse an d fin e vol tage co nt rol s for p recis e settab il ity an d are
capable of current output of 0-2A (0-3A for model 1761). The “third”
supply has a current output of 0-5A, allowing it to handle extensive
digital logic circuitry. Two large panel-mounted LED meter displays
can monitor either the output current or output voltage of each supply.
one of two tracking modes. In the series tracking mode, the “B” Supply
current setting of the two supplies can still be set independently when
in the series tracking o perating mode. In the series tr acking mode the
“A” and “B” supplies are con nected in series, allowing for double the
voltage setting
connected together in parallel, allowing for double the current setting.
“CV” (constant voltage) or “CC” (constant current) mode of operation.
load variations cau se the current to reach the pres et limit, the un it then
regulates output current rather than output voltage. Current limits are
adjustable from 5% to 100% of maximum.
be preset. When load variations cause current to drop below
the regulated value, the unit reverts to regulated voltage
operation at the preset value.
The “third” V supply is ideal for powering digital logic
circuitry. The 0-5 amp capacity allows the supply to be used
for large circuits. Built-in overload protection automatically
indicator lights when the supply is overloaded.
These models exhibit excellent regulation and low ripple
characteristics. The circuit design i ncorporates a pre-regulator,
which greatly reduces internal power dissipation at low output
voltages.
Reverse polarity prot ection 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
or (-) polarity may be strapped to ground, or either polarity
may be floated to an external voltage. Additionally, the two
“main” volt supplies can be used as a “split supply” with two
positive voltages and a common negative, two negative
voltages and a common pos
(independent) voltages.
6
The features and versatility of the unit, especially the triple output
supply for engineering lab applications. It can serve as a single or
voltage power source, including the bias supply, for
breadboard and prototype circuits and equipment. It can provide
amplifiers. It may be used as a battery eliminator, or to power
an be evaluated while powering a breadboard or
prototype circuit to determine the circuit’s power supply
The same features that make the Model 1760A a good
for school laboratories, and home use by electronic
and tracking features, make it an ideal general purpose power
multi-
single or simultaneously varying voltages for circuit evaluation. It
can provide trackin g (+) and (-) voltages for evaluating differential
individual circuit boards or cards while removed from the system.
Its output c
requirements. Its laboratory quality specifications will meet most
engineering laboratory requirements.
choice for an engineering lab also make it a good choice for
most other solid state electronic applications. These
applications include service shops; industrial production
testing of components, assemblies, and complete equipment;
hobbyists.
7
TRIPLE OUTPUT
tracks the “A” supply. Outputs can be strapped for two positive
doubles output voltage capability and
CONSTANT VOLTAGE OR CONSTANT CURRENT
output voltage or output current of all three supplies. Use of
Limits internal dissipation for higher reliability and
Fully adjustable current limiting (from 5% to 100% of
reverse polarity.
Operates as three separate power supplies. Each has floating
output and is completely isolated from the other two.
ONE 4-6.5 V (1760A) or 2-6.5 V (1761 & 1762) SUPPLY
Durable 0-to-5 amp supply is ideal for use with most digital
logic circuitry. Adequat e current capacity for ext ensive circuitry.
TWO 0-30V (model 1760A), 0-35V (model 1761), or 0-60V
(model 1762) SUPPLIES
“A” and “B” supply are continuously variable over their
respective voltage ranges with coarse and fine controls. Each
supply has a 2A (3A model 1761) current capacity.
UNIQUE TRACKING FEATURE
The “A” and “B” supplies can be operated so that the “B” supply
voltages with a common negative, two negative voltages with a
common positive, or one positive and one negative with a neutral
common.
SINGLE 0-60V (model 1760A), 0-70V (model 1761), or 0120V (model 1762) SUPPLY
Series tracking feature
allows use of “A” and “B” supplies combined as one supply.
SINGLE 0-30V, 4A (model 1760A), 0-35V, 6A (model
1761), or 0-60V, 4A (model 1762) SUPPLY
Parallel tracking feature doubles output current capability and
allows use of “A” and “B” supplies combined as one supply.
FEATURES
The “A” and “B” supplies provide regulated DC voltage
output or regulated DC current output. Crossover is smooth
and automatic.
LED DISPLAY
Two large, easy-to-read LED 4-digit displays monitor
two meters allows simultaneous current and voltage metering
when using “A” and “B” supplies in tracking operation. Good
visibility in bright or low light.
LABORATORY QUALITY
Excellent regulation, low ripple.
PRE-REGULATOR
efficiency.
ISOLATED OUTPUT
Either polarity may be floated or grounded.
OVERLOAD PROTECTION
maximum output current) for “A” and “B” supplies protects
circuit under test and the power supply.
REVERSE POLARITY PROTECTION
Prevents damage to power supply from external voltage of
8
“A” AND “B” SUPPLIES
Tracking Series, “B” trac ks “A”:
Output Voltage Range:
0V to 30V (model 1760A)
0V to 35V (model 1761)
0V to 60V (model 1762)
Output Current Limit Range:
0.1A to 2A (model 1760A and 1762)
0.1A to 3A (model 1761)
Load Regulation (Constant Voltage):
≤0.01% + 3 mV
Line Regulation 108 - 132 V (Constant Volta ge ):
≤0.01% + 3 mV
Ripple (Constant Voltage):
≤1 mV RMS
Recovery Time (Constan t Voltage):
≤100 uS
Temp. Coefficient (Constant Voltage):
<300 ppm/°C
Load Regulation (Constant Current):
≤0.2% + 3mA
Line Regulation 108 - 132 V (Constant Current):
≤0.2% + 3mA
Ripple Current (at 108 V for Constant Current):
≤3mA RMS
Tracking (Series) Accuracy:
±0.2% + 10mV
SPECIFICATIONS
5% to 100%
Panel Meter Accuracy (Volts):
±0.5% + 9 digits.*
Panel Meter Accuracy (Current):
±0.5% + 9 digits.*
(* see note 1)
“Third” SUPPLY
Output Voltage Range:
4V to 6.5V (2V to 6.5V model 1761)
Load Regulation (Constant Voltage):
≤10mV (0 to 5A load)
Line Regulation 108 - 132V (Constant Voltage):
≤10mV
Ripple and Noise:
≤2mV RMS
Over Voltage Protection Threshold:
6.8V to 7.3V
Panel Meter Accuracy:
Same as “A” Supply Meter.
9
SPECIFICATIONS
GENERAL
Dimensions (H x W x D):
Power Requirements:
Domestic: 120 VAC + 10%, 60 Hz
International: 120/220/230/ 24 0 V AC -* 10%, 50/60 Hz
Power Consumption (Fully Loaded):
Approximately 350 W
Protection:
Reverse polarity protection and current limiting.
NOTE: Specifications and information are subject to change without notice. Please visit www.bkprecision.com
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 su sceptible 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 supp ly to either slo wly increase or decr ease with the change in the power supply’s internal temperature. As the power
supply outputs more power its internal temperature will increase 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.
5.7" x 10.5" x 15" (145 mm x 267 mm x 381 mm)
Weight:
10 kg (21 lbs)
Accessories Supplied:
Two earth ground bus straps.
for the most current product
10
GENERAL CONTROLS AND INDICATORS
TRACKING Mode Switches. Two pushbutton switches that
1. 0-30V/4-6.5V Switch. Controls “A”/4-6.5V LED
(amps) position (in), current is read from the
. Digital display indicates
CONTROLS AND INDICATORS
8. POWER Switch. Turns power on and off.
9.
select INDEPendent mode, SERies trackin g mode, or PARallel
tracking mode as follows:
a. When INDEP/TRACK switch is disengaged (out), the unit
is in the INDEPendent mode and the “A” and “B” power
supplies are completely independent from one another.
b. When the INDEP/TRACK switch is engaged (in) and the
SER/PAR switch is disengaged (out), the unit is in the
TRACKing SERies mode. In this mode, maximum voltage
of both supplies is set using the “A” VOLTAGE controls
(voltage at output terminals of the “B” supply tracks the
voltage at the output terminals of the “A” supply). Also, in
this mode of operation the positive terminal (red) of the “B”
supply is internally connected to the negative terminal
(black) of the “A” supply. This allows the two supplies to be
used as one 0-to-60 volt supply.
c. When both INDEP/TRACK and SER/PAR switches are en-
gaged (in), the unit is in the TRACKing PARallel mode. In
this mode the “A” and “B ” supplies are wired together in
parallel and both the maximum cu rrent and voltage are set
using the “A” controls. The “A” and “B” outputs can be
used as two individual (but tracking) power supplies or just
the “A” output can b e used as a 0-to-30 volt supply with a 4
A capability.
Display. When this switch is in the 0-30V position (out),
the LED display monitors the “A” (0-30 V) supply.
When this switch is in the 4-6.5V positi on (in), the LED
display monitors the 4-6.5V supply.
2. Right V/A Sw itch. Selects current or voltage metering
mode for the “A” 0-30 V supply or the 4-6.5 V supply
(depending on setting of 0-30 V/4 -6.5 V switch ). When
in the A
“A”/4-6.5 V LED Display. When in the V (volts)
position (out), voltage is read from the “A”/ 4-6.5 V
LED Display.
3. “A”/4-6.5 V LED Display
voltage or current at the 0-30 V “A” supply or the 4-6.5
V supply (depending on the setting of the Right V/A and
0-30 V/4 -6.5 V switches).
4-6.5 V SUPPLY CONTROLS AND INDICATORS
4. “-” Terminal (Black). Negative polarity output terminal
for 4-6.5V supply.
5. “+” Terminal (Red). Positive polarity output terminal
for 4-6.5V supply.
6. Voltage Level Control. Adjusts output voltage for 4-
6.5V supply. Fully counterclockwise rotation adjusts
output voltage to 4V. Clockwise rotation increases
voltage to a maximum of 6.5V (full clo c kwi se ro t at ion ).
7. 5 A OVERload Indicator. Lights when load on 4-6.5
Volt supply becomes too large.
11
CONTROLS AND INDICATORS
Fig. 1. Front Panel Co ntrols and Indi cator s.
12
“A” SUPPLY CONTROLS AND INDICATORS
supply is in the Constant Current mode. The Power
adjustment control for the maximum output voltage of the
Fine adjustment of output
10. CURRENT Control. Adjusts current limit of “A”
stant voltage mode. Adjusts constant
supply in constant current mode.
mode. The Power Supply regulates the output current at
endent modes. Also lights
16. C.C. (Constant Cur rent) Indicator. Red LED lights when
“A”
Supply regulates the output current at the value set by the
“A” CURRENT control. In the Parallel Tracking mode,
when this indicator is lit, both the “A” and “B” sup plies are
in the Constant Current mode.
17. C.V. (Constant Voltage) Indicator. Green LED lights when
the “A” supply is in the Constant Voltage mode. The Power
Supply regulates the output voltage at the value set by the
“A” VOLTAGE controls. In either the Series or Parallel
Tracking mode, when this indicator is lit, both the “A” and
“B” supplies are in the Constant Voltage mod e.
18. Coarse VOLTAGE Control. Coarse adjustment of the
output voltage of the “A” supply. Also functions as coarse
“B” supply when either parallel or series tracking mode is
selected. Read the value on the “A”/4-6.5 V LED Display
when the voltage (V) and master (0-30 V) meterin g modes
are selected.
19. Fine VOLTAGE Control.
voltage of the “A” supply. Also fun ctions as fine adjustment
control for the maximum output voltage of the “B” supply
when either parallel or series tracking mode is selected. Read
the value on the “A”/4-6.5 V LED Display when the voltage
(V) and master (0-30 V) metering modes are selected.
CONTROLS AND INDICATORS
supply in con
current value of “A”
Current can be read from the “A”/4-6.5V LED Display
when the current (A) and master (0-30V) metering
modes are selected.
11. “+” Terminal (Red). Positive polarity output terminal
for the “A” supply. Also serves as the positive polarit y
terminal for 4 A parallel and 0-to-60 V series tracking
operation.
Terminal (Green). Earth and Chassis Ground.
12.
13. “-” Terminal (Black). Negative polarity output terminal
for the “A” supply. Also serves as the negative polarity
terminal for 4 A parallel tracking operation. In series
tracking op eration, this termin al is internally tie d to the
(+) positive terminal of the “B” supply.
“B” SUPPLY CONTROLS AND INDICATORS
14. C.V. (Constant Voltage) Indicator. Green LED lights
when the “B” supply is in the Constant Voltage mode.
The Power Supply regulates the output voltage at the
value s et b y the “B” VOLTAGE controls.
15. C.C. (Constant Current)/PARallel Indicator. Red
LED lights when “B” supply is in the Constant Current
the value set by the “B” CURRENT control when in the
series tracking or INDEP
when the TRACKing PARa llel mo de is selected.
13
CONTROLS AND INDICATORS
Fig. 2. Rear Panel Controls.
25. Coarse VOLTAGE Control. Coarse adjustment of the output
this terminal is
connected to the negative terminal of the “A” supply.
voltage of the “B” supply when the INDEPendent mode is
selected. Also sets the 5% to 100% tracking in the SERies
TRACKing mode. Disabled in the PARallel TRACKing mode.
Read the value on the “B” LED Display when the voltage (V)
metering mode is selected.
26. Fine VOLTAGE Control. Fine adjustment of output voltage of
the “B” supply when the INDEPendent mode is selected. Also
sets the 5% to 100% tracking in the SERies TRACKin g mode.
Disabled in the PARallel TRACKing mode. Read the value on
the “B” LED Di splay when the voltage (V) metering mode is
selected.
27. CURRENT Control. Adjusts current limit of “B” supply in
constant voltage mode. Adjusts current value of “B” supp ly in
constant current mode. Current can be read from the “B” LED
Display when the current (A) metering mode is selected.
28. Left V/A Switch. Selects current or voltage metering mode for
the 0-30 V “B” supply. When in the A (amps) position (in),
current is read form the “B” LED Display. When in the V
(volts) position (out), voltage is read form the “B” LED
Display.
29. “B” LED Display. Digital display indicates voltage or current
at the 0-30 V “B” supply (depending on the setting of the A/V
switch).
30. “+” Terminal (Red). Positive polarity output terminal for the
“B” supply. In series tracking operation,
20. Ter minal (Green). E arth and Chas sis Grou nd .
21. “-” Terminal (Black). Negative polarity output terminal
for the “B” supply. Also serves as the negative polarity
terminal for 0-to-60 V series tracking operation.
REAR PANEL CONTROLS
22. Fuse
23. Power Cord
24. 110/220 Line Voltage Conversion Swi tch
14
OPERATING INSTRUCTIONS
SAFETY PRECAUTIONS
power supply. When the unit is providing large
heat sink can become very hot. Contacting the
may contain high voltage and present a shock
hazard. Observe caution. If the power supply
output is floated (referenced to a voltage rather
ground.
EQUIPMENT PRECAUTIONS
Avoid using the power supply in ambient temperatures above
There is no need to worry about voltage spikes or overshoot
supplies only when they are used independently from one another.
endent operating mode, the operating
controls of the two power supplies are completely independent and
either supply can be used individually or both can be used
are covered in the APPLICATIONS section of this manual.
Avoid contacting the heat sink at the rear of the
amounts of current at any or all of its outputs, the
heat sink when it is hot could result in skin burns
or damage to the equipment in contact with them.
Use only a polarized 3-wire AC outlet. This as-
sures that the power supply chassis, case, and
ground terminal are connected to a good earth
ground and r educ es dang er fro m el ect ri cal sh ock .
There may be great danger of electrical shock if
the power supply output is connected to an external high voltage. Some equipment being powered
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
CAUTION
+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.
Do not exceed the voltage rating of the circuit being powered.
Many transistors and integrated circuits will not withstand voltage
of 30 volts.
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.
INDEPENDENT USE OF “A” OR “B” SUPPLY
The “A” and “B” supplies each provide a 0-to-30 volt output at
up to 2.0 amps. This procedure covers the use of the “A” and “B”
When used in the INDEP
simultaneously. Basic operation is covered here. Several variations
15
Hook-up
mode switch so that the
Turn off the power supply and the equipment to be powered
Connect the positive polarity of the device being powered to
powered is also the chassis or common, it may be
b. Similarly, the positive polarity can be grounded by
in Fig. 3C should also be used where it is not
ered is separate from both the positive and
is not equipped with reverse polarity protection,
1. Disengage the INDEP/TRACK
power supply is in the INDEPendent operating mode.
2.
during hook-up.
3.
the red (+) terminal of the power supply.
4. Connect the negative polarity of the device being powered to
the black (-) terminal of the power supply.
5. Fig. 3 illustrates the grounding possibilities when used in the
INDEPendent mode.
a. If the negative polarity of the equipment or circuit being
grounded to earth by strapping the black (-) terminal to
the green (
) terminal as shown in Fig. 3A.
OPERATING INSTRUCTIONS
strapping the red (+) terminal to the green ( )
terminal as shown in Fig. 3B.
c. If an earth ground reference is not required, the
configuration of Fig. 3C may be used. The scheme
known whether the chassis is common with either
the positive or negative polarity.
d. If the chassis or common of the equipment being
pow
negative polarity power inputs, use the connection
shown in Fig. 3D.
6. Observe proper polarity. If the circu it being powered
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 (-).
7. Make sure that the hook-up leads offer sufficient
current capability and low resistance between the
power supply and the circuits being powered.
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