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.
16
OPERATING INSTRUCTIONS
Fig. 3. Independent Ope rati on Groundi ng Po ssibili ties.
17
OPERATING INSTRUCTIONS
Fig. 3. Independent Ope rati on Groundi ng Po ssibili ties.
18
Fig. 4. Typical Cons tant Volt age O peratio n.
Typical Constant Voltage Operation
Before connecting the device to be powered to the power
afe load current for the
and connect it to the device to be
current metering mode and note the load current on the
1.
supply, determine the maximum s
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 counterclo ckwise).
3. Turn off power supply
powered (see “Hook-Up” procedure in this section).
4. Turn on POWER switch. The CV indic ator should l ight.
5. Set the meter selection switch to the V position to select the
voltage metering mode.
6. Increase the VOLTAGE setting until the LED display reads
the desired value. The Fine control permits easier setting to a
specific value.
7. Set the meter selection switch to the A position to select the
display.
8. 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.
OPERATING INSTRUCTIONS
19
OPERATING INSTRUCTIONS
Fig. 5. Setti ng Cur rent Li mit.
Setting Current Limit
control away from zero
control for the desired current limit.
The current limit (overload protection) has now been preset.
1. Determine the maximum safe current for the device to be
powered.
2. Temporarily short the (+) and (-) terminals of the power
supply together with a test lead.
3. Rotate the Coarse VOLTAGE
sufficiently for the CC indicator to light.
4. Set the meter selection switch to the A position to select the
current metering mode.
5. Adjust the CURRENT
Read the current value on the LED display.
6.
Do not change the CURRENT control setting after this step.
7. Remove the short between the (+) and (-) terminals and hook
up for constant voltage operation.
20
Fig. 6. Typi cal C onstant C urrent Oper atio n.
Typical Constant Current Operation
Turn off the power supply and connect it to the device to be
The CC indicator will not light if the load is less than 5% of
advance (before connecting the load) as prescribed earlier in the
increa se th e ou tp ut cur ren t.
1. Before connecting the device to be powered to the power suppl y,
determine the maximum safe voltage to be applied, set the meter
selection switch to the V position, and set the VOLTAGE
controls to obta in tha t voltag e readin g on the LED display.
2. Determine the desired constant current value.
3. Set the CURRENT control to minimum (fully counterclockwise).
4.
powered.
5. Turn on the power supply. The CC indicator should light if the
load is greater than 5% of full scale.
full scale or approximately 0.1A.
6. Set the meter selection switch to the A position to obtain the
current metering mode.
7. Increase the CURRENT con trol sett ing until th e desire d constant
current value is read on the display, or set the current limit in
“Setting Current Limit” procedure.
8. If the load current drops below the 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 control will not
NOTE
OPERATING INSTRUCTIONS
21
OPERATING INSTRUCTIONS
Figure 7. Constant Vol tag e/Constant Curre nt
Constant Voltage/Constant Current Characteristic
The working characteristic of this power supply is called a constant
sponse to the load change. The intersection of constant voltage and
constant current modes is called the crossover point. Fig. 7 shows the
the constant voltage mode, a regulated output voltage is provided. The
output voltage remains constant as the load increases, up until the point
current becomes constant and the output voltage drops in proportion to
further increases in load. The crossover point is indicated by the front
constant current mode, which may be adjusted for a 1 amp charging
oad decreases to the point where it no longer demands the full
l amp charging rate. This is the crossover point where the power supply
voltage/constant current automatic crossover type. This permits continuous transition from constant current to constant voltage modes in re-
relationship between this crossover point and the load.
For example, if the load is s uch that the power supply is op erating in
where the preset current limit is reached. At that point, the output
panel LED indicators. The crossover point is reached when the CV
indicator goes off and the CC indicator comes on.
Similarly, crossover from the cons tant 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
rate. As the battery becomes charged, and its voltage approaches 13.8
volts, its l
goes into the constant voltage mode.
Characteristics.
22
SERIES TRACKING OPERATION
supply. This allows the power
In the series tracking mode, the maximum output voltage of both
supplies can be simultaneously varied with one
Simultaneous metering of both current and voltage can be obtained
mode of operation by setting one of the displays for current
switch and releasing the
SER/PAR switch.
1. Set the 0-30 V/4-6.5 V switch to the 0-30 V
control. Follow the instructions for
Turn off the power supply and the equipment to be
Fig. 8 illustrates the grounding possibilities when
being powered is also the chassis or common, it
may be grounded to earth by strapping the black
When the series tracking mode of operation is selected, the positive
(red) terminal of the “B” supply output is internally connected to th e
negative (black) terminal of the “A”
supply to be used as a single 0-to-60 volt power supply simply by
using the negative (black) terminal of the “B” supply and the positive
(red) terminal of the “A” supply.
the “A” and “B”
control. The maximum “B” supply voltage can be set to the same
value of the “A” supply by setting the “B” Coarse and Fine
VOLTAGE controls fully clockwise, so that “B” is set to 100%
tracking.
in this
metering and one for voltage metering. In this case, the output voltage
(across the two supplies) is actually double the displayed value. For
example, if the “B” display is set for voltage metering and the “A”
display for current metering, the output voltage across the “A”
positive (red) terminal and the “B” negative (black) terminal would
be double the reading on the “B” LED Display (since both supplies
are putting out the same voltage). The actual output current would be
the valu e r ead fr o m th e “A” LED Dis pla y.
8. Set the power supplies to the TRACKING SERIES mode by
engaging the INDEP/TRACK
OPERATING INSTRUCTIONS
position, the “B” V/A switch to the V (voltage
metering) position, and the “A” V/A switch to the A
(current met er in g) po s ition .
2. Set the “B” Coarse and Fine Voltage and
CURRENT controls to the fu lly clockwi se pos ition.
The maximum current is set using the “A”
CURRENT
“Setting Cu rrent Limit” (INDEPENDENT USE OF
“A” OR “B” SUPPLY section of this manual) using
the “A” CURRENT control.
3. Adjust the output voltage to the desired level using
the “A” VOLTAGE controls (remember that the
actual output voltage is double the reading on the
“B” LED Display).
4.
powered during hook-up.
5. Connect the positive polarity of the device being
powered to the red (+) terminal of the “A” power
supply.
6. Connect the negative polarity of the device being
powered to the black (-) terminal of the “B” power
supply.
7.
the unit is used as a 0-to-60 volt supply.
a. If the negative polarity of the equipment or circuit
(-) terminal of the “B” supply to the green ( )
terminal of the “B” supply as shown in Fig. 8A.
23
OPERATING INSTRUCTIONS
Fig. 8. Series Tracking Operation Grounding Poss ibilities
24
OPERATING INSTRUCTIONS
Fig. 8. Series Tracking Operation Grounding Poss ibilities
25
OPERATING INSTRUCTIONS
Fig. 8. Series Tracking Operati on Grounding Po ssibili ties
a. Similarly, the positive polarity can be grounded by
If one of the supplied ground straps is to be used,
and negative terminals and load down the power
configuration of Fig. 8D may be used. The scheme in
Fig. 8D should also be used where it is not known
or common of the equipment being
powered is separate from both the positive and
negative polarity power inputs, use the connection
strapping the red (+) terminal of the “A” supply to the
green terminal of the “A” supply as shown in Fig. 8B.
b. If “split supply” operation is desired, a positive and
negative voltage with a center ground can be achieved
by strapping the black (-) terminal of the “A” supply
to the green ( ) of the “A” supply as shown in Fig.
8C. See the APPLICATIONS section of this manual
for more information on “split supply” operation.
NOTE
only use it in one of these three ways. Connecting
two ground straps could ground both the positive
supply, causing improper operation.
c. If an earth ground reference is not required, the
whether the chassis is common with either the positive
or negative polarity.
d. If the chassis
shown in Fig. 8E.
26
9. Observe proper polarity. If the circuit being powered is not equipped with
up leads offer sufficient current capability and
In the parallel tracking mode of operation, both supplies are strapped
(because each supply is providing the same amount of
supply output jacks, follow the instructions for “Setting Current
1. Adjust the output voltage to the desired level
being powered to the red (+) terminal of the
Fig. 9 illustrates the grounding possibilities
circuit being powered is also the chassis or
Similarly, the positive polarity can be
the configuration of Fig. 9C may be used.
The scheme in Fig. 9C should also be used
If the chassis or common of the equipment
eing powered is separate from both the
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 (-).
10. Make sure that the hook-
low resistance between the power supply and the circuits being powered.
PARALLEL TRACKING OPERATION
together (in parallel). This allows for a 0-30 V supply with a 4 amp current
capability. Only the “A” output terminals are used for parallel tracking
operation. In the parallel tracking mode, the “B” supply output voltage and
current track the “A” supply output voltage and current.
6. Set the power supplies to the TRACKING PARALLEL mode by
engaging both TRACKING switches (INDEP/TRACK and SER/PAR
switches).
7. Set the 0-30V/4-6.5V switch to the 0-30V position, the “A” V/A switch to
the V (voltage metering) position, and the “B” V/A switch to the A
(current metering) position. Output voltage will now be read from the “A”
LED Display. Output current is exactly double the value read from the
“B” LED Display
current).
8. Because both voltage and current of the “B” supply track the “A” supply,
the maximum current and voltage are set using the “A” controls. Using
the “A”
Limit” (INDEPENDENT USE OF “A” OR “B” SUPPLY paragraph of this
section). Remember that the actual current output at the “A” supply
output jacks is double th e re ading on the “B” LED Display.
OPERATING INSTRUCTIONS
using the “A” VOLTAGE controls.
2. Turn off the power supply and the equipment to
be powered during hook-up.
3. Connect the positive polarity of the device
“A” po wer supply.
4. Connect the negative polarity of the device
being powered to the black (-) terminal of the
“A” po wer supply.
5.
when used in the TRACKing PARallel mode.
a. If the negative polarity of the equipment or
common, it may be grounded to earth by
strapping the black (-) terminal to the green
(
) terminal as shown in Fi g. 9A.
b.
grounded by strapping the red (+) terminal to
the gre en (
c. If an earth ground reference is not required,
where it is not known whether the chassis is
common with either the positive or negative
polarity.
d.
b
positive and negative polarity power inputs,
use the connection shown in Fig. 9D.
) terminal as shown in Fig. 9B.
27
OPERATING INSTRUCTIONS
Fig. 9. Parallel Tracking Operation Grounding Possibilities
28
OPERATING INSTRUCTIONS
Fig. 9. Parallel Tracking Operation Grounding Possibilities
29
OPERATING INSTRUCTIONS
9. Observe proper polarity. If the circuit being powered is not
1. Fig. 10 illustrates the grounding possibilities of the 4-6.5V
If an earth ground reference is not required, the
equipped with revers e polarity protection, damage to t he circuit
can result from revers e polarity. Use color coded hook-up leads,
for convenience in i dentifying polarity, red f or (+) and black for
(-).
10. Make sure that the hook-up leads offer sufficient current
capability and low res istance between the p ower supply and t he
circuits being powered. 10-amp test leads are available as an
optional accessory.
4-6.5 V POWER SUPPLY OPERATION
The 4-6.5V s upply provides a 4 .0 to 6.5V DC output with a 5 amp
current capacity. The supp ly is idea l for us e with TTL circ uits.
5. Set the 0-30V/4-6.5V switch to the 4-6.5V position a nd the Right
V/A swi tch to the V p osition. This sets the “A”/4-6.5V Display
to show output voltage of the 4-6.5V supply.
6. Using the Voltage Level C ontrol to adjust the outp ut voltage of
the 4-6.5 V supply to the desir ed level.
7. Turn off the power supply and the equipment to be powered
during hook-up.
8. Connect the positive polar ity of the device being powered to the
red (+) terminal of the 4-6.5V supply.
9. Connect the negative polarity of the devic e being powered t o the
black (-) terminal of the 4-6.5V supply.
supply.
a. If the negative polarity of the equipment or circuit being
powered is also the chassis or com mon, it may grounded to
earth by connecting a jumper from the black (-) terminal to
either green (
b. Similarly, the positive polarity can be grounded by
connecting a jumper between the r ed (+) terminal and either
green (
c.
configuration of Fi g. 10C may be used. The scheme in Fig.
10C should also be used where i t is not known whether the
chassis is common with either the positive or negative
polarity.
d. If the chassis or common of the e quipment bei ng powered i s
separate from both the posi tive and negative polarity power
inputs, use the connection shown in Fi g. 10D.
2. Observe proper polarity. If the circuit being powered is not
equipped with reverse polar ity protec tion, damage t o the circuit
can result from reverse polarity. Use color coded hook-up
leads, for conven ience in identifying polari ty, red for (+) and
black for (-).
3. Make sure that the hook-up leads offer sufficient current
capability and low res ist a nce bet ween the p ower sup pl y and the
circuits being powered. 10-amp hook-up leads are a vailable as
an optional accessory.
4. Set the Right V/A switch to the A pos ition to moni tor the l oad
current.
) terminal as shown in Fig. 10A.
) terminal as shown in Fig. 10B.
30
OPERATING INSTRUCTIONS
Fig. 10. Grounding Possibilities for 4-6.5 V Power Supply
31
OPERATING INSTRUCTIONS
Fig. 10. Gr o unding Possibilities for 4-6.5 V Power Supply
32
10. If the red OVERload indicator lights, too much load has been placed
on the supply. This will cause voltage and current to drop and
situation, the load on the supply must be decreased so that no more
NOTE
to normal operation, the output
prevent proper operation of the 4-6.5V supply. To correct this
than 5 amps of current are required.
OPERATING INSTRUCTIONS
If decreasing the load d oes not cause
the overload indicator to turn off, the
overvoltage protection circuitry has
activated. In order to return the supply
voltage must be decreased (or the
external voltage source must be removed) and the power must be
momentarily shut of f.
33
APPLICATIONS
GENERAL
power supply has a very wide
facturing and testing facilities,
schools, and home hobbying. The “A” and “B” power supply
operate a module or circuit board on the test bench when it is
removed from its parent equipment. It can be used to power
players, auto sound systems, CB radios, etc. on the test bench.
volt electrical
Some servicing applications require the injection of a
equipment being tested may contain its own power supply
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
such as the base of that transistor. Varying the power supply
modules, subassemblies, and complete units in the
power source for testing purchased components and
This power supply is particularly well suited for
will cause the CC indicator to light, and the unit can be
The Model 1760A/1761/1762
variety of applications in electrical and electronics servicing,
engineering laboratories, manu
outputs are fully adjustable from 0-30V (1760A), 0-35V (1761), or
0-60V (1762) and 0-2A (1760A and 1762) or 0-3A (1761) and the
4-6.5V (1760A) or 2-6.5V (1761 & 1762) supply is fully adjustable
with a current capability of 0-5A. This flexibility makes it suitable
for most applications requiring a DC power source.
ELECTRONICS SERVICING
Most electronics trou blesho oting and repair is performed on a test
bench. This power supply can provide the DC power source to
portable, battery-operated equipment and check the effect of low
battery voltage. It can power vehicular equipment such as tape
Parallel tracking supplies up to 4 amps, adequ ate surge current for
most vehicular equipment.
Most automobiles and other vehicles use 12systems. 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.
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 1760A. The
and operate from AC power. A DC vol tage may already be
supply output is then applied to another point in the circuit,
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
production and assembly area or in the quality control ar ea.
The instrument can be used in incoming inspection as a DC
subassemblies.
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 display. The current limit can be set so
that all units which do not meet the load current specification
34
ELECTRONICS DESIGN LAB
The technician or engineer working in an engineering laboratory
power supply to power breadboard and prototype
Use of the instrument in an engineering laboratory is very similar
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
The student in an electronics curriculum 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
nts in fundamental
specifications for proper voltage and current settings.
Charging information is sometimes printed on the batteries.
current mode of operation. Before connecting the power
than the power supply’s maximum load current, set the
he power supply output and the
charging current will taper off. The power supply may
When this occurs, the power supply will continue to provide
er supplies” are required for
ideally suited for “split power supply” operation. This
supply can be configured to provide two positive voltages
common positive, or one positive and one negative with a
common ground. In addition, each of these configurations
requires a DC
circuits. This power supply is ideal because it monitors output
current and voltage, limits current to protect the circuit, is adjustable
over a wide range, and has excellent regulation and very low ripple.
to that described for servicing electronics equipment and modules,
damage.
ELECTRONICS EDUCATION
classroom laboratory to conduct experime
electronics. In learning Ohm’s law, for example, the relationships of
resistance, current, and voltage are easily d emonstrated by the u se of
a power supply.
BATTERY CHARGING
charge in rechargeable batteries such as lead-acid, nickel-cadmium,
and some alkaline types. Refer to the battery manufacturer’s charging
The power supply can be used as a battery charger to restore the
APPLICATIONS
Battery charging, at least initially, requires the constant
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
CURRENT control to maximum). The CC indicator will
light and the battery will charge at the preset current limit.
As the battery approaches full charge, its terminal voltage
will approach that of t
automatically switch to CV (constant voltage) operation.
a trickle charge.
SPLIT SUPPLY
Frequently, “split pow
amplifier and other electronic circuits. The Model 1760 A is
with a common negative, two negative voltages with a
can be obtained with identical or differing voltages.
35
APPLICATIONS
Fig. 11. Typical Hook-Up Using Tw o Identi cal
Positive Voltages and a Common Negative.
Two Identical Positive Voltages With a Common
voltages with a common negative. A good example of this would
common negative. Using both supplies in the parallel tracking
Turn off the power supply and the equipment to be powered
Connect the positive polarity inputs of the circuit to be
powered to the positive (red) terminals of the supplies and
Negative (Refer To Fig. 11)
Some electronic equipment requires two identical positive
be a digital car clock where there are two +12 volt inputs and a
mode would provide the simplest hook-up and operation. This
type of “split supply” operation is obtained as follows:
1. Connect a ground strap between the “A” supply’s ne gative
terminal and ground.
2. Set the desired voltage and maximum current using the “A”
VOLTAGE and CURRENT controls.
3.
during hook-up.
4.
connect the common negative input of the circuit to be
powered to the “A” supply’s negative (black) or ground
(green) terminal.
36
Fig. 12. Typical Hook-Up Using Tw o Diff erent
Positive Voltages and a Common Negative.
Two Differing Positive Voltages With a Common Negative
with a common negative. A typical example of this would be a
endent operating mode and set up the LED
Turn off the power supply and the equipment to be powered
s of the circuit to be
powered to the positive (red) terminal of the supply. Connect
the common negative input of the circuit to be powered to
(Refer To Fig. 12)
Many electronic circuits require two different positive voltages
device that uses both TTL (+5 V) and analog (typically +15 V)
circuitry. Using both suppli es, two differing positive volta ges with
a common negative a re ob t ain ed as fol lo ws:
1. Select the INDEP
displays so that both displays monitor voltage.
2. Connect the ground straps between each supplies’ negative
terminal and ground.
3. Independently set the desired voltage and maximum current
for the “A” and “B” supplie s using the “A” VOL TAGE and
CURRENT controls and the “B” VOLTAGE and
CURRENT contro ls r esp ectively.
4.
during hook-up.
5. Connect the positive polarity input
either the supply’s negative (black) or ground (green)
terminal.
6. If desired, set the LED displays to monitor current.
APPLICATIONS
37
APPLICATIONS
Fig. 13. Typical Hook-Up Using Two Identical
Two Identical Negative Voltages With a Common Positive
(Refer To Fig. 13)
When the same negative voltage i s required at two point s in the
same circuit and a common positive is needed, perform the
following:
1. Connect the ground strap between the positive terminal and
the ground of the “A” supply.
2. Set the desired voltage and maximum current using the “A”
VOLTAGE and CURRENT controls.
3. Turn off the power supply and the equipment to be powered
during hook-up.
4. Connect the negative polarity inputs of the circuit to be
powered to the negative (black) terminals of the supplies.
Connect the common positive input of the circuit to be
powered to the “A” suppl y’s positive (red) or ground (green)
terminal.
Negative Voltages and a Common Positive.
38
Fig. 14. Typical Hook-Up Using Tw o Diff erent
Two Differin g Ne gati ve Vol tage s Wi th a Posi tive C ommon
endent operating mode and set up the LED
ired voltage and maximum current
Turn off the power supply and the equipment to be powered
polarity inputs of the circuit to be
Connect the common positive input of the circuit to be
(Refer To Fig. 14 )
Using both supplies, two differing negative voltages with a
common positive are obtained as follows:
1. Select the INDEP
displays so that both displays monitor voltage.
2. Connect the ground straps between each supplies’ positive
terminal and ground.
3. Independently set the des
for the “A” and “B” supplies using the “A” VOLTAGE and
CURRENT controls and the “B” VOLTAGE and CURRENT
controls respectively.
4.
during hook-up.
5. Connect the negative
powered to the negative (black) terminals of the supplies.
powered to either supplies’ positive (red) or ground (green)
terminal.
6. If desired, set the LED displays to monitor current.
APPLICATIONS
Negative Voltages and a Common Positive.
39
APPLICATIONS
Fig. 15. Typical Hook-Up Using I denti cal Positi ve
and Negative Voltages with a Sep ar at e C ommo n .
Identical Positive and Negative Voltages With a Separate
Turn off the power supply and the equipment to be powered
Common (Refer To Fig. 15)
Another typical “split supply” application is when a circuit uses
operational amplifiers (op-amps). Typically, identical positive and
negative voltages are required to power op-amp circuits. Using both
supplies and the series tracking mode of operation, identical positive
and negative voltages with a separate common are obtained as follows:
1. Select the TRACKing SERies operating mode and set A/B
Metering switch to monitor the “A” sup ply.
2. Set the desired voltage using the “A” VOLTAGE controls.
3. Connect a ground wire between the “A” supply negative terminal
and the GND (green ) ter mi na l.
4.
during hook-up.
5. Connect the positive polarity input of the circuit to be powered to
the positive (red) terminal of the “A” supply and connect the
negative polarity of the circuit to the negative terminal of the “B”
supply. Connect the circuit ground to the ground terminal of the
“A” supply, the positive terminal of the “B” supply, or the GND
(green) terminal.
40
Fig. 16. Typical Hook-Up Using Different Positive
Differing Positive and Negative Voltages With a Separate
Using both supplies and the series tracking mode of operation,
current will usually be different for each of the supplies in this
supply will
automatically vary the same percentage.
Common (Refer To Fig. 16)
different positive and negative voltages with a separate common
utilizing th e variable “B tracks A” mode of operation are obtained
as follows:
1. Select the TRACKing SERies operating mode and set up the
LED displays to monitor voltage.
2. Connect one ground strap between the ground terminal and
the negative terminal of the “A” supply and the other between
the ground terminal and the positive terminal of the “B”
supply.
3. Set the desired voltage for each supply using the VOLTAGE
controls. Set the maximum current using the CURRENT
controls.
4. Turn off the power supply and the equipment to be powered
during hook-up.
5. Connect the positive polarity input of the circuit to be
powered to the positive (red) terminal of the “A” supply and
connect the negative polarity of the circuit to the negative
terminal of the “B” supply. Conn ect the circuit ground to the
ground terminal of either the “A” or “B” supply.
6. If desired, set th e LED displays to monitor curr ent. The load
configuration.
7. The advantage of this con figuration over the independent on e
is that if the +12 V “A” supply is varied to simulate a -10% to
+10% voltage variation, the -5 V “B”
APPLICATIONS
and Negative Voltages and a Separate Common.
41
WARNING
The following instructions are for use by qualified personnel
only. To avoid electrical shock, do not perform any servicing
supply will not operate. The fuse should not normally open unless
a problem has developed in the unit. Try to determine and correct
120 V
3.5A
Slow Blow
LINE VOLTAGE CONVERSION, INTERNATIONAL UNITS
supply can be switched from 110VAC to
other than contained in the operating instructions unless you are
qualified to do so.
Line voltage is exposed when the top cover is removed from the
power supply, and is present on the fuseholder and power switch
even when the unit is turned off.
FUSE REPLACEMENT
If the fuse blows, the LED indicator will not light and the power
the cause of the blown fuse, then replace only with a fuse of the
correct rating as listed in Table 1. The fuse is located on the rear
panel (see Fig. 2).
OPERATION FUSE VALUE TYPE
220/230/240 V 1.5A Slow Blow
Table 1. Fuse Val ues
MAINTENANCE
This power
220/230/240VAC by a switch locat ed o n th e rear p anel . To select
the desired line voltage, si mply insert the fuse and fuse h older so
that the appropriate voltage is pointed to by the arrow. Be sure to
use the proper vale fuse (see l abel on rear panel).
42
MAINTENANCE
ADJUSTMENTS
This unit was accurately adjusted at the factory before
eadjustment is recommended only if repairs have
1/2 digit
If readjustment is required, use the following procedure. All
l/2 digit
Table 2. Functions of Cali bration Adj ustment s
ADJ
FUNCTION OF ADJ
LOCATION OF A DJ
R6
“A” SUPPLY +5 V REF.
MAIN BO ARD
R10
“B” SUPP LY +5 V RE F.
MAIN BO ARD
R119
“B” SUPP LY S ERI ES
TRACKING
MAIN BO ARD
R122
4-6.5V A METER & A
LIMIT
MAIN BO ARD
R133
4-6.5V V METER
MAIN BO ARD
R134
4-6.5V 3.9V REF.
MAIN BO ARD
R159
4-6.5V 6.8V REF.
MAIN BO ARD
R163
“A” S UPP LY A ME TE R
MAIN BO ARD
R164
“B” SUPP LY A M ETE R
MAIN BO ARD
R304L
“B” SUPPLY V ME TE R
“B” PANEL M E TER
R304R
“A” SUPPLY V METER
“A” P ANEL METER
shipment. R
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 4multimeter with an accuracy of ±0.1% dcv or better is available
(B+K Precision Model 391A or equivalent).
references to left and right are correct when facing the front of
the supply. The functions of the adjustments are shown in Table
2 and their locations are shown in F i g. 18.
I. “A” SUPPLY AND “A” METERING ADJUSTMENTS
1. Connect an accurate (±0.1%) external 4-
multimeter to measure the DC voltage at the output
terminals of the “A” SUPP LY.
2. Disengage the INDEP/TRACK mode switch (out) so that
the power supply is in the INDEPendent operating mode .
3. Set the “A” VOL TAGE controls (both Coarse and Fine)
to maximum (fully clockwise).
4. Adjust R6 (“A” SUPPLY +5 V REF) on the main circuit
board (located on the right rear side of the supply) for a
reading as close to 30.40 volts (on the multimeter) as
possible.
5. Set the 0-30 V/4-6.5V switch to the 0-30V position and the
Right V/A switch to the V position.
1. Adjust R304 (“A” SUPPLY V METER ADJ) on
the “A” panel meter board (located on the right side
of the supply behind the “A”/4-6.5V LED Display)
for a reading of 30.4 volts on the “A”/4-6 .5V LED
Display.
2. Set the “A” Coarse VOLTAGE control for a
reading of approximately 05.0 volts on the “A”/4-
6.5V LED Dis play.
43
MAINTENANCE
Fig. 18. Location of Adjustments (Main Circuit Board).
44
MAINTENANCE
3. Set the Right V/ A switch to th e A position.
output terminals to read the output current (so that the meter
6.5V METERING
1. Connect a 1 Ω load (rated at 30W or more) and the
1/2 digit
panel board (located on the left side of the supply
4. Connect the external multimeter across the “A” SUPPLY
causes a short circuit across the terminals) and adjust the “A”
CURRENT control so that 2.00 amps is read on the “A”/4-
6.5V LED Dis play.
5. Adjust R163 (“A” SUPPLY A METER ADJ) so that the
multimeter also reads 2.00 amps.
II. 4-6.5V SUPPLY AND 4ADJUSTMENTS
5. Set the 0-30V/4-6.5V switch to the 4-6.5V position and the
Right V/A switch to the V position.
6. Connect an accurate (±0.1%) external 4-1/2 digit multimeter
across the output terminals of the 4-6.5V SUPPLY to read
output voltage and adjust the 4-6.5V front panel voltage level
control to minimum (4V, fully counterclockwise).
7. Adjust R134 (4-6.5V 3.9V REF) located on the main board
for a reading of 3.90 volts on the external multimeter.
8. Adjust R133 (4-6.5V V M ETER ADJ) located on the main
board so that the “A”/4-6.5 V LED Dis play reads 3.90 volts.
9. Set the Right V/ A switch to th e A position.
10. Turn R122 (4-6.5V A METER & A LIMIT ADJ) and
R159 (4-6.5V 6.8V REF) located on the main board fully
clockwise.
multimeter in series across the output terminals of the 4-
6.5V SUPPLY to read the output current.
2. Adjust the 4-6.5V voltage level control to obtain an
output of 5.30 amp s (r ead on the multimeter).
3. Adjust R122 (4-6.5V A METER & A LIMIT ADJ) so
that the “A”/4-6.5 V LE D Di spla y also reads 5.30 amps.
4. Slowly Adjust R159 (4-6.5V 6.8V REF)
counterclockwise until the OVER indicator on the
1760 Front Panel just light s.
III. “B” S UPPL Y AN D M ETER ING ADJ USTM ENTS
1. Connect an accurate (±0.1%) external 4-
multimeter to measure the DC voltage at the output
terminals of the “B” SUPPLY.
2. Disengage the INDEP/TRACK mode switch (out) so
that the power supply is in the INDEPendent operating
mode.
3. Set the “B” VOLTAGE controls (both Coarse and
Fine) to maximum (fully clockwise).
4. Adjust R10 (“B” SUPPLY +5V REF) on the main
board for as close to 30.70 volts (on the multimeter) as
possible.
5. Set the Left V/ A switch to the V position.
6. Adjust R304 (“B” SUPPLY V METER ADJ) on the
“B”
behind the “B” LED Display) for a reading of 30.7
volts on the “B” LED Di spl ay.
45
7. Set the “B” Coarse VOLTAGE control for a reading of
1. Connect the multimeter to the “A” SUPPLY outputs
output terminals and verify that the
Because of the specialized skills and test equipment
required for instrument repair and calibration, many
cies for this purpose. To use this
approximately 05.0 volts on the “B” LED D ispl ay.
8. Set the Left V/ A switch to the A position.
9. Connect the external multimeter across the “B” SUPPLY
output terminals to read the output current (so that the meter
causes a short circuit across the terminals) and adjust the “B”
CURRENT control so that 2.00 amps is read on the “B” LED
Display.
10. Adjust R164 (“B” SUPPLY A METER ADJ) so that the
multimeter also reads 2.00 amps.
IV. “B” SERIES TRACKING ADJUSTMENT
4. Set the supply to the TRACKing SERies mode by engaging
the INDEP/TRACK switch and releasing the SER/PAR
switch.
5. Set the “B” VOLTAGE controls (both Coarse and Fine) to
maximum (fully clockwise).
6. Set the “A” VOLTAGE controls (both Coarse and Fine) to
maximu m (fu l l y clockwise).
MAINTENANCE
and measure the voltage.
2. Disconnect the multimeter from the “A” SUPPLY
outputs and connect it to the “B” SUPPLY outputs.
3. Adjust R119 (SERIES TRACKING ADJ) (lo cated on
the MAIN board) until the voltage read from the
multimeter is the same as it was across the “A”
SUPPLY output terminals. Return the multimeter to
the “A” SUPPLY
output voltage is identi cal. If not, repea t this step.
INSTRUMENT REPAIR SERVICE
customers prefer to rely upon B+K Precision for this
service. We maintain a network of B+K Precision
authorized service agen
service, even if the instrument is no longer under warranty,
follow the instructions given in the WARRANTY
SERVICE INSTRUCTION section of this manual. There
is a nominal charge for instruments out of warranty.
46
Service Information
Warranty Servic e: 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 and 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&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&K Precision Corp.
B&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.
47
Limited Two-Year Warranty
Model Number: ______________
Date Purchased: _______________ _
B&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&K Precision Corp. will, without charg e, repair or repl ac e, at its opti on, def ec tive 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 www.bkprecision.com
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&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&K Precision Corp.
22820 Savi Ranch Parkway
Yorba Linda, CA 92887
www.bkprecision.com
714-921-9095
within fifteen (15) days of purchase.
48
TEST INSTRUMENT SAFETY
(continued from inside front cover)
4. 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 equipmen t.
5. 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.
6. 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 an AC outlet.
7. 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.
8. Never work alone. Someone should be nearby to render aid if necessary. Training in CPR (cardio-pulmonary resuscitation) first
aid is highly recommended.
49
22820 Savi Ranch Parkway
Yorba Linda, CA 92887
www.bkprecision.com
© 2012 B&K Precision Corp.
V042313
Printed in Taiwan
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