BK Precision BK Precision 1651A Manual

INSTRUCTION

MANUAL

El Manual de la Instrucción

MODELS 1651A & 1652

MODELOS 1651A & 1652

Triple Output

DC POWER SUPPLY

FUENTES DE PODER

De Triple Salida DC

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176

TestEquipmentDepot.com

TEST INSTRUMENT SAFETY

WARNING

Normal use of test equipment exposes you to a certain amount of danger from electrical shock because testing must sometimes be
performed where exposed high voltage is present. An electrical shock causing 10 milliamps of current to pass through the heart will
stop most human heartbeats. Voltage as low as 35 volts dc or ac rms should be considered dangerous and hazardous since it can
produce a lethal current under certain conditions. Higher voltages are even more dangerous. Your normal work habits should
include all accepted practices to prevent contact with exposed high voltage, and to steer current away from your heart in case of
accidental contact with a high voltage. Observe the following safety precautions:

1. There is little danger of electrical shock from the dc output of this power supply. However, there are several other possible test
conditions using this power supply that can create a high voltage shock hazard:
a. If the equipment under test is the “hot chassis” type, a serious shock hazard exists unless the equipment is unplugged (just

turning off the equipment does not remove the hazard), or an isolation transformer is used.

b. If the equipment under test is “powered up” (and that equipment uses high voltage in any of its circuits), the power supply

outputs may be 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)

Instruction Manual

Triple Output

DC POWER SUPPLY

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176

TestEquipmentDepot.com

TABLE OF CONTENTS

TEST INSTRUMENT SAFETY........inside front cover

INTRODUCTION.........................................................1

FEATURES ...................................................................3

SPECIFICATIONS.......................................................5

CONTROLS AND INDICATORS ..............................7

“A” Supply Controls And Indicators...............................7

“B” Supply Controls and Indicators................................9

Fixed 5 V Supply Terminals and Indicator ...................10

Rear Panel Controls ......................................................10

OPERATING INSTRUCTIONS ...............................12

Safety Precautions.........................................................12

Equipment Precautions .................................................12

Independent Use of “A” or “B” Supply ........................12

Series Tracking Operation.............................................18

Page

Page

Parallel Tracking Operation...................................... 22

Fixed 5 V Power Supply Operation.......................... 25

APPLICATIONS.................................................... 29

General ..................................................................... 29

Electronics Servicing................................................ 29

Electronics Manufacturing........................................29

Electronics Design Lab............................................. 30

Electronics Education............................................... 30

Battery Charging ......................................................30

Split Supply.............................................................. 30

MAINTENANCE ................................................... 37

Fuse Replacement..................................................... 37

SERVICE INFORMATION.................................. 38

LIMITED ONE-YEAR WARRANTY ................. 39

SPANISH MANUAL............................................... 41

INTRODUCTION

The B & K-Precision Models 1651A & 1652 Triple Output
DC Power Supplies are high quality, general purpose dc power
sources. They provide two supplies with a 0-24 volt dc output
and one with a fixed 5 volt dc output. The 0-24V supplies are
adjustable and are capable of current output of 0-0.5 amp. The
fixed 5V supply has a current output of 0-4 amps, allowing it
to handle extensive digital logic circuitry. Two panel mounted
meters can simultaneously monitor the output current and
output voltage of either of the 0-24V supplies.

The two 0-24 volt supplies can be operated independently or
in one of two tracking modes. In the series tracking mode, the
“B” supply tracks the voltage of the “A” supply. In the series
tracking mode the “A” and “B” supplies are connected in
series, allowing a single output of 0-48V at up to 0.5 amps. In
the parallel tracking mode, the two supplies are connected in
parallel, allowing a single 0-24V output at up to 1 amp.

Both 0-24 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 Constant Current mode of operation. In
constant voltage applications, a current limit may be preset.
When load variations cause the current to reach the preset
limit, the unit then regulates output current rather than output
voltage. Current limits are adjustable from 6% to 100% of
maximum. In constant current applications, the maximum
voltage may be preset. When load variations cause current to
drop below the regulated value, the unit reverts to regulated
voltage operation at the preset value.

The fixed 5V supply is ideal for powering digital logic
circuitry. The 0-4 amp capacity allows the supply to be used
for large circuits. Built-in overload protection automatically
limits the current output to a maximum of 4 amps. An LED
indicator lights when the supply is overloaded.

These supplies exhibits excellent regulation and low ripple
characteristics. The circuit design incorporates a pre-regulator,
which greatly reduces internal power dissipation at low output
voltages.

Reverse polarity protection prevents accidental damage to
the power supply from improper connection to an external
voltage, and current limiting protects the equipment being
powered, as well as the power supply.

The output is isolated from chassis and earth ground, which
permits full flexibility of connections. When needed, the (+) or
(-) polarity may be strapped to ground, or either polarity may
be floated to an external voltage. 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 positive, or one positive, one negative, and a
common. All of these configurations can be used with either
matching (tracking) or differing (independent) voltages.

1

INTRODUCTION

The features and versatility of these units, especially the
triple output and tracking features, make them an ideal
general purpose power supply for engineering lab
applications. They can serve as a single or multi-voltage
power source, including the bias supply, for breadboard and
prototype circuits and equipment. They can provide single or
simultaneously varying voltages for circuit evaluation. They
can provide tracking (+) and (-) voltages for evaluating
differential amplifiers. They may be used as a battery
eliminator, or to power individual circuit boards or cards
while removed from the system. Their output can be
evaluated while powering a breadboard or prototype circuit to
determine the circuit’s power supply requirements. Their
laboratory quality specifications will meet most engineering
laboratory requirements.

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176

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The same features that make the Model 1651A and 1652 a
good choice for an engineering lab also make them a good choice
for most other solid state electronic applications. These
applications include service shops; industrial production testing
of components, assemblies, and complete equipment; for school
laboratories, and home use by electronic hobbyists.

2

FEATURES

TRIPLE OUTPUT

Operates as three separate power supplies. Each has floating

output and is completely isolated from the other two.

ONE FIXED 5V SUPPLY

0-to-4 amp f
digital logic circuitry. Adequate current capacity for extensive
circuitry.

TWO 0-24 VOLT SUPPLIES
“A” and “B” supplies are continuously variable over 0-to-24

volt range. Each supply 0.5 amp current capacity.

UNIQUE TRACKING FEATURE
The two 0-to-24 V supplies can be operated so that the “B”

supply tracks the “A” supply. Outputs can be strapped for two
positive voltages with a common negative, two negative
voltages with a common positive, or one positive and one
negative with a neutral common.

SINGLE 0-48V SUPPLY
Series tracking feature allows use of “A” and “B” supplies as

one 0-to-48 V, 0.5 amp supply.

ixed 5 volt supply is ideal for use with most

SINGLE 0-24V 1 AMP SUPPLY
Parallel tracking feature allows use of “A” and “B”

supplies as a 0-to-24 V supply with a 1 amp current capacity
(through “A” output terminals).

CONSTANT VOLTAGE OR CONSTANT CURRENT
The “A” and “B” supplies provide regulated dc voltage

output or regulated dc current output. Crossover is smooth
and automatic.

METERING
Two, easy-to-read meters monitor output voltage and

output current of the “A” and “B” supplies. Use of two
meters allows simultaneous current and voltage metering
when using “A” and “B” supplies in tracking or independent
operation.

LABORATORY QUALITY

Excellent regulation, low ripple.

LED INDICATORS

Identify mode of operation.

PRE-REGULATOR
Limits internal dissipation for higher reliability and

efficiency.

3

FEATURES

ISOLATED OUTPUT

Either polarity may be floated or grounded

OVERLOAD PROTECTION
Fully adjustable current limiting (from 6% to 100%

of 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 reverse polarity.

HOOK-UP CABLES

Supplied with three sets of red and black hook-up leads.

4

SPECIFICATIONS

“A” AND “B” SUPPLIES

Output Voltage Range:

0V to 24VDC (0 ± 100mV)

Output Current Limit Range:

0 to 0.5A.

Constant Voltage Operation:

Voltage Regulation:
Load: ≤0.01% + 3mV
Line (108 – 132V): ≤0.01% + 3mV

Ripple Noise: ≤2mVrms (5Hz to 1MHz)

Recovery Time: ≤100us typical.

Temp. Coefficient
0°C to 40°C ≤300ppm/°C

Tracking Error:
No Load: ≤0.2% + 20mV
Full Load: ≤0.2% + 100mV

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176

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Constant Current Operation:

Adjustable Current Limits: ≤30mA to ≥500mA

Current Regulation:
Load: ≤0.2% + 6mA.
Line (108 – 132V): ≤0.2% + 3mA.

Ripple Current and Noise: ≤3mA rms.

Metering (“A” & “B” only):

Voltmeter:
Range: 0 to 25V
Accuracy: ≤2.5% of Full Scale

±2% + 2 digits
(1652)

Ampmeter:
Range: 0 to 600mA
Accuracy: ≤2.5% of Full Scale

±2% + 2 digits
(1652)

5

SPECIFICATIONS

FIXED 5V SUPPLY

Output Voltage: 5V ± 100mV.
Maximum Current: ≥4A.
Load Regulation: ≤10mV.

Line Regulation 108 – 132 V: ≤5mV
Ripple And Noise: ≤5mV rms (5 Hz to 1

MHz)
Overvoltage Protection
Threshold: 5.7 to 6.5 V

GENERAL

Power Requirements: 100/120/220/240VAC ±10%,

50/60Hz.

Power Consumption: 165VA.

Protection: Reverse polarity, overvoltage

and current limiting.

NOTE: Specifications and information are subject to change without notice.

Temperature Range
& Humidity:
Operation: 0°C to 40°C <80% R.H.
Storage: -20°C to 60°C <70%

R.H.

Dimensions (HxWxD): 4.5 x 11.75 x 10.375”

(114 x 298 x 264 mm)

Weight: 4.8 kg (10.6 lbs)

Accessories Supplied: Hook-Up Cables, 3 pair

(Black & Red).
Power Cord.
Spare Fuse.
Instruction Manual

6

CONTROLS AND INDI

CATORS

1. POWER Switch. Turns power on and off.

2. Power ON light. Red LED lights to indicate a power on
condition.

3. GND Terminal (Green). Earth and Chassis Ground.

4. A/B Metering Switch. Selects simultaneous Voltage &
Current metering for the “A” or “B” supplies. When in the
A position, the V and mA meters are connected to the “A”
supply. When in the B position, the V and mA meters are
connected to the “B” supply.

5. V Meter. Indicates voltage on the “A” or “B” supply
depending on the position of the A/B Metering switch.

6. mA Meter. Indicates current on the "A" or "B" supply
depending on the position of the A/B Metering switch.

7. Zero Adjusts. Mechanical zero adjusts for the V & mA
Meters thru the front panel with a slotted screwdriver.

8. TRACKING/INDEPENDENT Mode Switch: Three
Position switch that selects INDEPENDENT mode,
PARALLEL TRACKING mode, or SERIES TRACKING
mode of the “A” and “B” supplies as follows:

a. When the switch is in the right position, the unit is

in the INDEPENDENT mode and the “A” and “B”
power supplies are completely independent from
one another.

b. When the switch is in the middle position, the

unit is in the PARALLEL TRACKING mode. In
this mode the “A” and “B” supplies are wired
together in parallel and both the maximum
current 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 be used as a 0-to-24
volt supply with a 1 A capability.

c. When the switch is in the left position, the unit is

in the SERIES TRACKING 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 0­to-48 volt supply.

“A” SUPPLY CONTROLS AND INDICATORS

9. VOLTAGE Control. Adjusts the output voltage of the
“A” supply. Also functions as the adjustment control for
the maximum output voltage of the “B” supply when either
parallel or series tracking mode is selected. Voltage can be
read from the V Meter when the A Metering mode is
selected.

7

CONTROLS AND INDICATORS

Figure 1. Front panel controls and indicators

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176

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8

CONTROLS AND INDICATORS

10. CURRENT Control. Adjusts current limit of “A”
supply in constant voltage mode. Adjusts constant
current value of “A” supply in constant current mode.
Adjusts the constant current value of the “B” supply
when either SERIES or PARALLEL TRACKING is
selected. Current can be read from the mA Meter
when the A Metering mode is selected.

11. “+” Terminal (Red). Positive polarity
for the “A” supply. Also serves as the positive polarity
terminal for 0-to-48 V, 1A parallel tracking and 0-to­48 V, 0.5A series tracking operation.

12. “-” Terminal (Black). Negative polarity output
terminal for the “A” supply. Also serves as the
negative polarity terminal for 0-to-24 V, 1 A parallel
tracking operation. In series tracking operation, this
terminal is internally tied to the (+) positive terminal
of the “B” supply.

13. CONSTANT CURRENT Indicator.

a. Red LED lights when “A” supply is in the

Constant Current mode. The Power Suppl
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” supplies are in the Constant Current mode.

b. When the LED is off, 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 off,
both the A”A and “B” supplies are in the Constant
Voltage mode.

output terminal

“B” SUPPLY CONTROLS AND INDICATORS

14. VOLTAGE Control. Adjusts the output voltage of the
“B” supply when the INDEPENDENT mode is selected.
Voltage can be read on the V Meter when the B Metering
mode is selected. Control is disabled when TRACKING
mode is selected.

15. CURRENT Control. Adjusts current limit of “B” supply
in constant voltage mode. Adjusts constant current value
of “B” supply in constant current mode. Current can be
read from the mA Meter when the current mA Metering
mode is selected. Control is disabled when TRACKING
mode is selected.

16. “+” Terminal (Red). Positive polarity output terminal
for the “B” supply. In series tracking operation, this
terminal is connected to the negative terminal of the “A”
supply.

17. “-” Terminal (Black). Negative polarity output
terminal for the “B” supply. Also serves as the negative
polarity terminal for 0-to-48 V series tracking operation.

y

18. CONSTANT CURRENT Indicator

a. Red LED lights when “B” supply is in the

Constant Current mode. The Power Supply
regulates the output current at the value set by
the “B” CURRENT control when in the
Independent mode.

b. When LED is off, the “B” supply is in the

Constant Voltage mode.

9

CONTROLS AND INDICATORS

FIXED 5V SUPPLY TERMINALS AND INDICATOR

19. “+” Terminal (Red). Positive polarity output terminal
for FIXED 5V supply.

20. “-“ Terminal (Black). Negative polarity output terminal
for FIXED 5V supply.

21. OVERLOAD Indicator. Lights when load on FIXED 5
Volt supply becomes too large.

REAR PANEL CONTROLS

22. LINE VOLTAGE SELECT Switches. Combination
settings allow Universal Power Operation;

23. Line Cord Receptacle. Fuse.

10