x
P6021A
60 MHz, 15 Amp AC Current Probe
ZZZ
Instruction Manual
*P071300400*
071-3004-00
xx
P6021A
60 MHz, 15 Amp AC Current Probe
ZZZ
Instruction Manual
www.tektronix.com
071-3004-00
Copyright © Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its subsidiaries or suppliers, and are protected by
national copyright laws and international treaty provisions.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes that in all previously
published material. Specifications and price change privileges reserved.
TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.
Contacting Tektronix
Tektronix, Inc.
14150 SW Karl Braun Drive
P.O . B o x 500
Beaverton, OR 97077
USA
For product information, sales, service, and technical support:
In North America, call 1-800-833-9200.
Worldwide, visit www.tektronix.com to find contacts in your area.
Warranty
Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If
any such product proves defective during this warranty period, Tektronix, at its option, either will repair the defective product without charge for parts
and labor, or will provide a replacement in exchange for the defective product. Parts, modules and replacement products used by Tektronix for
warranty work may be new or reconditioned to like new performance. All replaced parts, modules and products become the property of Tektronix.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty period and make
suitable arrangements for the performance of service. Customer shall be responsible for packaging and shipping the defective product to the service
center designated by Tektronix, with shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the shipment is to a
location within the country in which the Tektronix service center is located. Customer shall be responsible for paying all shipping charges, duties,
taxes, and any other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate maintenance and care. Tektronix
shall not be obligated to furnish service under this warranty a) to repair damage resulting from attempts by personnel other than Tektronix
representatives to install, repair or service the product; b) to repair damage resulting from improper use or connection to incompatible equipment; c) to
repair any damage or malfunction caused by the use of non-Tektronix supplies; or d) to service a product that has been modified or integrated with
other products when the effect of such modification or integration increases the time or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THE PRODUCT IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR
IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. TEKTRONIX' RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY
PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS
ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
[W2 – 15AUG04]
Table of Contents
General safety summary .................................................................................................................... v
Service safety summary.................................................................................................................... ix
Compliance Information ..................................................................................................................... x
Certifications and Compliances ....................................................................................................... x
Environmental Considerations....................................................................................................... xiii
Preface..................................................................................................................................... xiv
Documentation....................................................................................................................... xiv
Conventions Used in This Manual................................................................................................... xiv
Returning the Probe for Servicing ...................................................................................................xv
Key Features ............................................................................................................................... 1
Installation .................................................................................................................................. 2
Controls and Indicators..................................................................................................................... 3
Functional Check . .......................................................................................................................... 6
Accessories and Options................................................................................................................... 7
Standard Accessories ................................................................................................................ 7
Optional Accessories . ............................................................................................................... 10
Options ............................................................................................................................... 12
Table of Contents
P6021A Current Probe Instruction Manual i
Table of Contents
Basic Operation............................................................................................................................ 13
Probing Principles ......................................................................................................................... 15
Application Examples...................................................................................................................... 21
Specifications.............................................................................................................................. 27
Performance Verification .................................................................................................................. 37
Increasing Sensitivity ................................................................................................................ 15
Common Mode Noise/Magnetic Field Errors........................................................................................ 16
Maximum Current Limits............................................................................................................. 17
Inductance Measurements .......................................................................................................... 22
Measuring Inductor Turns Count .................................................................................................... 25
Warranted Characteristics ........................................................................................................... 28
Typical Characteristics............................................................................................................... 29
Nominal Characteristics ............................................................................................................. 36
Equipment Required................................................................................................................. 38
Equipment Setup..................................................................................................................... 39
Midband Accuracy ................................................................................................................... 40
Rise Time and Bandwidth ........................................................................................................... 43
Time Constant ....................................................................................................................... 45
TestRecord .......................................................................................................................... 48
Adjustments................................................................................................................................ 49
Prerequisites . ........................................................................................................................ 49
Equipment Required................................................................................................................. 49
ii P6021A Current Probe Instruction Manual
Table of Contents
Remove the Compensation Box Cover . . . .......................................................................................... 50
Midband Accuracy ................................................................................................................... 53
HF Compensation.................................................................................................................... 54
Maintenance . . . ............................................................................................................................ 56
Cleaning.............................................................................................................................. 56
Index
P6021A Current Probe Instruction Manual iii
Table of Contents
iv P6021A Current Probe Instruction Manual
General safety summary
Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it.
To avoid potential hazards, use this product only as specified.
Only qualified personnel should perform service procedures.
While using this product, you may need to access other parts of a larger system. Read the safety sections of the other component
manuals for warnings and cautions related to operating the system.
To avoid fire or personal injury
General safety summary
Connect and disconnect properly.
source.
Connect and disconnect properly.
Connect and disconnect properly.
circuit under test. Connect the probe reference lead to the circuit under test before connecting the probe input. Disconnect the probe
input and the probe reference lead from the circuit under test before disconnecting the probe from the measurement instrument.
Observe all terminal ratings.
manual for further ratings information before making connections to the product.
Do not connect a current probe to any wire that carries voltages above the current probe voltage rating.
Do not operate without covers.
Do not operate with suspected failures.
service personnel.
P6021A Current Probe Instruction Manual v
Do not connect or disconnect probes or test leads while they are connected to a voltage
De-energize the circuit under test before connecting or disconnecting the current probe.
Connect the probe output to the measurement instrument before connecting the probe to the
To avoid fire or shock hazard, observe all ratings and markings on the product. Consult the product
Do not operate this product with covers or panels removed.
If you suspect that there is damage to this product, have it inspected by qualified
General safety summary
Avoid exposed circuitry.
Do not touch exposed connections and components when power is present.
Do not operate in wet/damp conditions.
Do not operate in an explosive atmosphere.
Keep product surfaces clean and dry.
vi P6021A Current Probe Instruction Manual
Terms in this manual
These terms may appear in this manual:
General safety summary
WARNING.
CAUTION.
Warning statements identify conditions or practices that could result in injury or loss of life.
Caution statements identify conditions or practices that could result in damage to this product or other property.
Symbols and terms on the product
These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the marking.
WARNING indicates an injury hazard not immediately accessible as you read the marking.
CAUTION indicates a hazard to property including the product.
P6021A Current Probe Instruction Manual vii
General safety summary
The following symbol(s) may appear on the product:
viii P6021A Current Probe Instruction Manual
Service safety summary
Service safety summary
Only qualified personnel should perform service procedures. Read this
before performing any service procedures.
Do not service alone.
first aid and resuscitation is present.
Disconnect power.
power.
Use care when servicing with power on.
battery (if applicable), and disconnect test leads before removing protective panels, soldering, or replacing components.
To avoid electric shock, do not touch exposed connections.
Do not perform internal service or adjustments of this product unless another person capable of rendering
To avoid electric shock, switch off the instrument power, then disconnect the power cord from the mains
Dangerous voltages or currents may exist in this product. Disconnect power, remove
Service safety summary
General safety summary
and the
P6021A Current Probe Instruction Manual ix
Compliance Information
Compliance Information
This section lists the safety and environmental standards with which the instrument complies.
Certifications and Compliances
EC Declaration of Conformity - Low Voltage
Compliance was demonstrated to the following specification as listed in the Official Journal of the European Communities:
Low Voltage Directive 2006/95/EC.
EN 61010-1:2001. Safety requirements for electrical equipment for measurement control and laboratory use.
EN 61010-2-032:2002. Particular requirements for handheld current clamps for electrical measurement and test equipment.
U.S. Nationally Recognized Testing Laboratory Listing
UL 61010-1 2004, 2ndEdition. Standard for electrical measuring and test equipment.
IEC 61010-2-032:2002. Particular requirements for handheld current clamps for electrical measurement and test equipment.
x P6021A Current Probe Instruction Manual
Compliance Information
Canadian Certification
CAN/CSA C22.2 No. 61010-1-04. Particular requirements for electrical equipment for measurement, control, and laboratory
use. Part 1.
CAN/CSA C22.2 No. 61010-2-032:04. Particular Requirements for Hand Held Current Clamps for Electrical Measurement
and Test.
Additional Compliance
IEC 61010-1:2001. Safety requirements for electrical equipment for measurement, control, and laboratory use.
IEC 61010-2-032:2002. Particular requirements for handheld current clamps for electrical measurement and test equipment.
Equipment Type
Measurement
Pollution Degree Descriptions
A measure of the contaminates that could occur in the environment around and within a product. Typically the internal environment
inside a product is considered to be the same as the external. Products should be used only in the environment for which they
are rated.
P6021A Current Probe Instruction Manual xi
Compliance Information
Polution Degree 1. No pollution or only dry, nonconductive pollution occurs. Products in this category are generally
encapsulated, hermetically sealed, or located in clean rooms.
Polution Degree 2. Normally only dry, nonconductive pollution occurs. Occasionally a temporary conductivity that is caused by
condensation must be expected. This location is a typical office/home environment. Temporary condensation occurs only
when the product is out of service.
Polution Degree 3. Conductive pollution, or dry, nonconductive pollution that becomes conductive due to condensation. These
are sheltered locations where neither temperature nor humidity is controlled. The area is protected from direct sunshine,
rain, or direct wind.
Polution Degree 4. Pollution that generates persistent conductivity through conductive dust, rain, or snow. Typical outdoor
locations.
Pollution Degree
Pollution Degree 2 (as defined in IEC 61010-1). Note: Rated for indoor use only.
xii P6021A Current Probe Instruction Manual
Environmental Considerations
This section provides information about the environmental impact of the product.
Product End-of-Life Handling
Observe the following guidelines when recycling an instrument or component:
Compliance Information
Equipment recycling.
contain substances that could be harmful to the environment or human health if improperly handled at the product’s end of life. To
avoid release of such substances into the environment and to reduce the use of natural resources, we encourage you to recycle this
product in an appropriate system that will ensure that most of the materials are reused or recycled appropriately.
This symbol indicates that this product complies with the applicable European Union requirements according to
Directives 2002/96/EC and 2006/66/EC on waste electrical and electronic equipment (WEEE) and batteries.
For information about recycling options, check the Support/Service section of the Tektronix Web site
(www.tektronix.com).
P6021A Current Probe Instruction Manual xiii
Production of this equipment required the extraction and use of natural resources. The equipment may
Preface
Preface
This manual describes the installation and operation of the P6021A current probe. Basic probe operations and concepts are
presented in this manual. You can also access the Tektronix Web site for this document and other related information.
Documentation
To read about Use these documents
First time operation, functional check, operating basics,
specifications, performance verification
In-depth oscilloscope operation, user interface help, GPIB
commands
*
To access the documentation that is installed on your instrument, click
Read this Instruction Manual.
Access the online help from the Help menu on the host
instrument.
in the taskbar and select
Start
*
Programs > TekApplications
.
Conventions Used in This Manual
The following icon is used throughout this manual to indicate a step sequence.
xiv P6021A Current Probe Instruction Manual
Returning the Probe for Servicing
If your probe requires servicing, you must return the probe to Tektronix. If the original packaging is unfit for use or not available, use
the following packaging guidelines:
Preparation for Shipment
Use a corrugated cardboard shipping
1.
carton having inside dimensions at
least one inch greater than the probe
dimensions. The box should have a carton
test strength of at least 200 pounds.
Put the probe into an antistatic bag or wrap
2.
it to protect it from dampness.
Place the probe into the box and stabilize it
3.
with light packing material.
Seal the carton with shipping tape.
4.
Preface
Refer to
5.
beginning of this manual for the shipping
address.
P6021A Current Probe Instruction Manual xv
Contacting Tektronix
at the
Key Features
Key Features
Use the P6021A current probe to make accurate measurements up to 60 MHz. Key features include:
>60 MHz bandwidth, ≤5.8nsrisetime
15 A p-p continuous rating
(de-rated with frequency)
250 A peak pulse current
(pulse widths <10 μs)
150 V CAT Il (bare wire)
300 V CAT Il (insulated wire)
1 P6021A Current Probe Instruction Manual
Installation
Align the BNC connector on the probe to
1.
the oscilloscope input connector.
Push in the probe connector and turn it to
2.
the right to lock it in place.
To disconnect the probe, turn the probe
connector to the left and pull the probe away
from the instrument.
Installation
P6021A Current Probe Instruction Manual 2
Controls and Indicators
Controls and Indicators
Controls and indicators for the probe are covered in the sections that follow.
Slider and Conductor Jaw
When the slider is in the locked position,
1.
you can degauss the probe and take
measurements.
Move the slider to the unlocked position to
2.
insert and remove conductors to and from
the jaw.
Thejawcanaccepta5mm(0.2in)
3.
diameter maximum conductor size.
WARNING.
force conductors larger than 5 mm (0.2 in)
diameter into the jaw.
To prevent probe damage, do not
3 P6021A Current Probe Instruction Manual
Safe handling zone – keep fingers behind
4.
demarcations when taking measurements.
WARNING.
To avoid electrical shock, do not
access the area beyond the safe handling zone
(indicated by the shaded area) when you take
measurements.
Controls and Indicators
WARNING.
To prevent probe damage, do not
drop the probe or subject it to impact.
WARNING.
Do not connect the current probe
to any wire that carries voltages or currents that
exceed the rating of the probes.
P6021A Current Probe Instruction Manual 4
Controls and Indicators
Range Select
Use the range select switch to change the
probe sensitivity between 2 mA/mV and
10 mA/mV.
Some oscilloscopes have an
NOTE.
attenuation control to match the oscilloscope
scaling to the probe sensitivity (range).
The correct oscilloscope attenuation settings to
use with the P6021A probe are:
2X for the 2 mA/mV range
10X for the 10 mA/mV range
5 P6021A Current Probe Instruction Manual
Functional Check
The following procedure checks that your probe is functioning properly. To verify that your probe meets the warranted specifications,
refer to the
Performance Verification
Functional Check
procedures. (See page 37.)
CAUTION.
conductors larger than 5.0 mm diameter into the probe jaw. Damage to the probe may result.
To check that your probe functions correctly,
do the following:
1.
2.
3.
4.
P6021A Current Probe Instruction Manual 6
The probe jaw opening accommodates insulated conductors with a diameter of 5.0 mm or less. Do not insert
Connect the probe to any channel of the
oscilloscope.
Set the oscilloscope to display the probe
channel.
Clamp the probe to your circuit.
Adjust the oscilloscope or use the Autoset
function to display a stable waveform.
When you see a stable waveform, your
probe is functioning correctly.
Accessories and Options
Accessories and Options
This section lists the standard and optional accessories available for the probe, and provides information on how to use the
accessories. Specifications are provided where appropriate so that you can choose the accessory that best fits your needs.
Standard Accessories
Probe Ground Lead
Fasten the small clip to the ground stub on
1.
the probe body.
Clip the alligator clip to your circuit ground.
2.
Attach the probe to your circuit.
3.
Reorder Tektronix part number:
196-3521-xx, qty. 1
7 P6021A Current Probe Instruction Manual
NylonCarryingCasewithPouch
and Inserts
Use the carrying case to hold the probe, the
accessories, and the instruction manual.
Place the probe, accessories, and manual
1.
in the carrying case.
Close the carrying case to transport the
2.
accessories to another location or for
storage.
Reorder Tektronix part number:
016-1952-xx
Accessories and Options
P6021A Current Probe Instruction Manual 8
Accessories and Options
Instruction Manual
The instruction manual provides operating and
maintenance instructions.
Reorder Tektronix part number:
071-3004-xx
Manuals in the languages listed below are
available for this product. Other languages may
also be available; check the Tektronix Web site
at www.tektronix.com/manuals.
(Japanese)
(Simplified Chinese)
9 P6021A Current Probe Instruction Manual
Optional Accessories
This section lists the optional accessories that you can purchase to help you with your probing tasks.
Current Loop
This 1-turn, 50 Ω current loop is required for
the performance verification procedures. The
BNC connector allows for easy connections to
current sources, and the conductor bar inside
the fixture fits in the jaw of the current probe.
To use the current loop, follow the procedure
for the specific task that you are performing
(for example, Performance Verification or
Adjustments).
Order Tektronix part number:
067-2396-xx
Accessories and Options
P6021A Current Probe Instruction Manual 10
Accessories and Options
Deskew/Calibration Fixture
Connect this fixture to host instruments that
support the probe calibration or deskew
procedures. The deskew procedures
compensate for gain errors and timing
differences between current and voltage
probes. Refer to your oscilloscope manual or
fixture documentation for instructions.
Order Tektronix part number: 067-1686-xx
11 P6021A Current Probe Instruction Manual
Options
Service Options
Accessories and Options
Option C3.
Option C5.
Option D1.
Option D3.
Option D5.
Option R3.
Option R5.
P6021A Current Probe Instruction Manual 12
Calibration Service 3 years
Calibration Service 5 years
Calibration Data Report
Calibration Data Report, 3 years (with Option C3)
Calibration Data Report, 5 years (with Option C5)
Repair Service 3 years
Repair Service 5 years
Basic Operation
Basic Operation
CAUTION.
surfaces of the probe head transformer are precision-polished and should be handled with care. Measurements may be degraded
by dirt on the mating surfaces of the probe head transformer. Refer to the Maintenance section of this manual for information on
how to properly clean the probe head transformer surfaces.
Do not force conductors larger than 5.0 mm (0.20 in) into the probe jaws. Damage to the probe may result. The mating
Grounding the Probe
The 6-inch ground lead grounds the shield around the probe transformer at the probe end of the cable. This allows you to move
the ground connection closer to the circuit you are measuring, thereby improving high frequency response. The ground lead
clips onto the ground connector on the bottom of the probe.
When you take high frequency measurements, connect the probe ground lead to the probe ground connector and attach the
alligator clip directly to RF ground to improve EMI rejection at high frequencies (2 MHz and above). This will help bypass
capacitively-coupled RF currents which can flow into the probe cable. In some cases, it may be helpful to move the ground lead or
reposition the probe away from noise sources in the circuit under test.
13 P6021A Current Probe Instruction Manual
Clip the ground lead to the ground post at
1.
the bottom of the probe head.
Connect the alligator end of the clip to the
2.
circuit ground.
Clamp the probe around the circuit
3.
conductor.
Basic Operation
P6021A Current Probe Instruction Manual 14
Probing Principles
Probing Principles
The following information is provided to help you use the full potential of your current probe.
Increasing Sensitivity
If you are measuring low-frequency AC signals
of very small amplitudes, you can increase
measurement sensitivity of your probe by doing
the following:
Wind several turns of the conductor under
1.
test around the probe as shown. The
signal is multiplied by the number of turns
around the probe.
Divide the displayed amplitude by the
2.
number of turns.
For example, if a conductor is wrapped around
the probe three times and the oscilloscope
shows a reading of 3 mA, the actual current
flow is 3 mA divided by 3, or 1 mA.
Winding more turns around the probe increases the insertion impedance and reduces the upper bandwidth limit of the probe.
NOTE.
15 P6021A Current Probe Instruction Manual
Common Mode Noise/Magnetic Field Errors
Common-mode noise at high frequencies and
strong magnetic fields on the supply side of
your circuit can cause measurement errors. To
avoid this:
Measure on the low or ground side of your
1.
circuit.
Orient the probe to measure conventional
2.
current flow (from positive to negative).
This method works best when the
NOTE.
negative terminal shown in the diagram is tied
to earth ground.
Probing Principles
P6021A Current Probe Instruction Manual 16
Probing Principles
Maximum Current Limits
Current probes have three maximum current ratings: pulsed, continuous, and Ampere-second product. Exceeding any of these
ratings can saturate the probe core, which magnetizes the core and causes measurement errors. Refer to the specifications for the
maximum current ratings of the probe. (See Table 2 on page 29.)
Maximum Pulsed Current (I
maxP
)isthe
maximum peak value of pulsed current the
probe can accurately measure, regardless
of how short (within bandwidth limitations)
the pulse duration is.
Maximum Continuous Current (I
maxC
)isthe
maximum current that can be continuously
measured at a specified AC frequency.
The maximum continuous current value is
derated with frequency; as the frequency
increases, the maximum continuous
current rating decreases.
17 P6021A Current Probe Instruction Manual
Ampere-Second Product is the maximum
width of pulsed current that you can
measure when the pulse amplitude is
between the maximum continuous and
maximum pulsed current specifications.
The maximum continuous specification
varies by frequency.
To determine if your measurement exceeds
the Ampere-second product, you must first
determine the maximum allowable pulse width
or maximum allowable pulse amplitude, as
described in the following section.
Probing Principles
P6021A Current Probe Instruction Manual 18
Probing Principles
Maximum Allowable Pulse Width
To determine the maximum allowable pulse
width do the following:
Measure the peak current of the pulse.
1.
Divide the Ampere-second (or
2.
Ampere-microsecond) specification
for the probe by the measured peak current
of the pulse:
The quotient is the maximum allowable
pulse width (PW
Check that the pulse width at the 50% point
3.
of the measured signal is less than the
calculated maximum allowable pulse width
(PW
max
).
max
).
19 P6021A Current Probe Instruction Manual
Maximum Allowable Pulse Amplitude
To determine the maximum allowable pulse
amplitude do the following:
Measure the pulse width at the 50% points.
1.
Divide the Ampere-second (or
2.
Ampere-microsecond) specification
for the range setting of the probe by the
pulse width.
The quotient is the maximum allowable
pulse amplitude; the peak amplitude of the
measured pulse must be less than this
value.
For example, the P6021A probe has a
maximum Ampere-second product of 500 A-μs.
If a pulse measured with the probe has a width
of 11 μs, the maximum allowable peak current
would be 500 A-μs divided by 11 μs, or 45.5 A.
Probing Principles
P6021A Current Probe Instruction Manual 20
Application Examples
Application Examples
This section explains ways to use your probe in common troubleshooting tasks and how to extend the use of your measurement
system.
21 P6021A Current Probe Instruction Manual
Inductance Measurements
You can use the current probe to measure the inductance of coils that have either a low-impedance or high-impedance pulse
source of a known value.
Low-Impedance Pulse Sources
This figure shows a constant-voltage pulse
generator of extremely low output impedance
connected to an inductor that has low
resistance.
Connect the inductor across the output
1.
terminals of the pulse generator.
Maintain a constant voltage across the
2.
inductor.
Clamp the current probe over one of the
3.
source leads.
If the probe impedance is a significant
NOTE.
part of the total circuit inductance, measurement
accuracy will be affected. Refer to the probe
specifications for probe insertion impedance.
Application Examples
P6021A Current Probe Instruction Manual 22
Application Examples
Measure the current ramp. The inductance
4.
is effectively defined by the slope of the
current ramp shown here.
Calculate the inductance using the
5.
following formula:
where:
L
is the inductance in henries,
E
is the voltage of the pulse generator,
dt
is the change in time, and
di
is the change in current.
23 P6021A Current Probe Instruction Manual
High-Impedance Pulse Sources
If the pulse source has a higher impedance of
known resistance, such that the output voltage
drops as the current increases, the inductance
of a coil can be calculated by the time constant
of the charge curve.
The current ramp shows how the values for the
inductance formula are obtained.
Use this formula to calculate the inductance
based on the current measurement:
where:
L
is the inductance in henries,
τ
is the time required for the current to rise
or fall 63.2% of the total current value, and
R
is the source resistance of the pulse
generator.
Application Examples
P6021A Current Probe Instruction Manual 24
Application Examples
Measuring Inductor Turns Count
To obtain an approximate turns count of an
inductor, do the following:
Connect the inductor to a current limited
1.
source, as shown.
Measure the input current on one of the
2.
inductor leads.
Clamp the current probe around the
3.
inductor and note the current value.
The number of turns is equal to the ratio of coil
current to input current.
The accuracy of this method is limited by the
current measurement accuracy.
25 P6021A Current Probe Instruction Manual
For a more precise turns count, you need a
coil with a known number of turns to use as a
reference. Do the following:
Repeat steps 1 and 2 above and make the
1.
following changes:
Insert the reference coil into the current
2.
probe.
Insert the test coil into the current probe
3.
so that the currents oppose each other
as shown. You must observe the polarity
of coil current to determine whether the
test coil has less or more turns than the
reference coil. The turns are calculated by
using the formula:
where:
is the number of turns in the test coil,
N
2
is the number of turns in the reference
N
1
coil,
is the measured coil current, and
I
m
is the input current.
I
1
Application Examples
P6021A Current Probe Instruction Manual 26
Specifications
Specifications
The specifications in Tables 1 through 5 are valid under the following conditions:
The probe has been calibrated at an ambient temperature of 23 °C ±5 °C.
The probe is connected to a host instrument with an input impedance of 1 M Ω.
The probe must have a warm-up period of at least 20 minutes and be in an environment that does not exceed the limits
described. (See Table 1).
Specifications for the current probe fall into three categories: warranted, typical, and nominal characteristics.
27 P6021A Current Probe Instruction Manual
Warranted Characteristics
Warranted characteristics describe guaranteed performance within tolerance limits or certain type-tested requirements. Warranted
characteristics that have checks in the
Table 1: Warranted electrical characteristics
Characteristic Description
Midband accuracy
Rise time (10% to 90%)
Bandwidth (-3 dB) 2 mA/mV: 1 kHz to 60 MHz guaranteed, 450 Hz to 60 MHz typical (20 to 30 °C)
Probe time constant
Performance Verification
±3%
≤5.8 ns
10 mA/mV: 300 Hz to 60 MHz guaranteed, 150 Hz to 60 MHz typical (20 to 30 °C)
2 mA/mV: >159 μs guaranteed, >355 μstypical(20to30°C)
10 mA/mV: >530 μs guaranteed, >1 ms typical (20 to 30 °C)
section are marked with the
Specifications
symbol.
P6021A Current Probe Instruction Manual 28
Specifications
Typical Characteristics
Typical characteristics describe typical but not guaranteed performance.
Table 2: Typical electrical characteristics
Characteristic Description
Maximum continuous current
Maximum DC saturation current
Maximum peak pulse current
Insertion impedance
Signal delay
Tilt
Phase response
2mA/mV-5A
10 mA/mV - 15 A
sine wave between 450 Hz and 10 MHz
p-p
sine wave between 150 Hz and 100 kHz
p-p
0.5 A
10 mA/mV range: 250 A peak
2 mA/mV range: 150 A peak
not to exceed 500 A μs, or 5 A
RMS
(See Figure 3 on page 32.)
0.035 Ω @1MHz
0.09 Ω @10MHz
0.5 Ω @60MHz
(See Figure 2 on page 31.)
11.8 ns
2 mA/mV: 2.8% or less within 10 μsofstep
10 mA/mV: 7.5% or less within 100 μsofstep
Between ±90° from 100 Hz to 20 MHz, greater than -270° at 60 MHz
29 P6021A Current Probe Instruction Manual
Characteristic Description
Maximum voltage on bare wire
Maximum voltage on insulated wire
Maximum Amp·Second product 500 A·μs (See page 17,
150 V CAT lI
300 V CAT lI
Maximum Current Limits
Figure 1: Frequency derating (continuous peak current versus frequency)
Specifications
.)
P6021A Current Probe Instruction Manual 30
Specifications
Figure 2: Typical insertion impedance versus frequency
31 P6021A Current Probe Instruction Manual
Figure 3: Maximum peak pulse versus pulse width
Specifications
P6021A Current Probe Instruction Manual 32
Specifications
Table 3: Environmental characteristics
Characteristic Description
Temperature
Humidity
Altitude
Operating: 0 to +50 °C (+32 to +122 °F)
Nonoperating: -40 to +75 °C (-40 to +167 °F)
Operating: 5-95% RH, tested up to +30 °C (+86 °F)
5-85% RH, tested at +30 °C to +50 °C (+86 °F to +122 °F)
Nonoperating: 5-95% RH, tested up to +30 °C (+86 °F)
5-85% RH, tested at +30 °C to +75 °C (+86 °F to +167 °F)
Operating: Up to 3000 meters (10,000 feet)
Nonoperating: Up to 12,192 meters (40,000 feet)
33 P6021A Current Probe Instruction Manual
Table 4: Typical mechanical characteristics
Characteristic Specification
Dimensions (See Figure 4 on page 35.)
Compensation box
Probe head 148 mm × 15.2 mm × 30.5 mm
Jaw opening (maximum measurable conductor size) 5 mm (0.20 in)
Cable length (from probe head to compensation box) 1.5 m (59 in)
Unit weight
Probe only
Probe, accessories, and packaging
73 mm × 30.5 mm × 40.6 mm
(2.9 in × 1.2 in × 1.6 in)
(5.8 in × 0.6 in × 1.2 in)
279 g ( 10.0 oz)
700 g (1.5 lb)
Specifications
P6021A Current Probe Instruction Manual 34
Specifications
Figure 4: Mechanical dimensions
35 P6021A Current Probe Instruction Manual
Nominal Characteristics
Nominal characteristics describe guaranteed traits, but the traits do not have tolerance limits.
Table 5: Nominal electrical characteristics
Characteristic Description
Input coupling
Current range 2 mA/mV: 5 A
Power requirement
Termination
Oscilloscope compatibility Oscilloscopes with a 1 MΩ BNC input
AC
p-p
10 mA/mV: 15 A
p-p
Supplied by host instrument
Terminate output into 1 MΩ
Specifications
P6021A Current Probe Instruction Manual 36
Performance Verification
Performance Verification
The procedures that follow verify the warranted specifications of the probe, listed below. The recommended calibration interval is
one year.
Midband accuracy
Rise time
Bandwidth
Time constant
Perform the following verification procedures in the order listed.
37 P6021A Current Probe Instruction Manual
Equipment Required
Table 6 lists the equipment required for the performance verification procedure.
Table 6: Test equipment
Description and quantity Performance requirement Recommended example
Oscilloscope TekVPI interface, 500 MHz or greater bandwidth Tektronix DPO4000
Calibration generator ACA: 0 to ±1 A, 50 Hz, square wave output
Digital multimeter (DMM) ≥2 volt range, ≥1% accuracy
HF current loop
BNC cable (2) 50 Ω,0.76m(30in)length
Test lead Banana plugs at both ends, lead diameter not to
Adapter (2) BNC-to-dual banana
Adapter
Adapter
1
Nine-digit part numbers (xxx-xxxx-xx) are Tektronix part numbers
ACV0to2V
, 50 kHz, sine wave output
RMS
Rise time ≤1ns
50 Ω ±0.5%, BNC male connector
exceed5mm(0.2in)
BNC-T
SMA male-to-BNC female
Performance Verification
1
Fluke 9100
Keithley 2700
067-2396-xx
012-0117-xx
012-0039-00
103-0090-xx
103-0030-xx
015-1018-xx
P6021A Current Probe Instruction Manual 38
Performance Verification
Equipment Setup
Use the following procedure to set up and warm up the equipment to test the probe.
Turn on the oscilloscope.
1.
Connect the probe to any channel of the
2.
oscilloscope.
Set the oscilloscope coupling to AC.
3.
Power on the remaining test equipment.
4.
Allow 20 minutes for the equipment to
5.
warm up.
Photocopy the test record and use it to
6.
record the test results. (See page 48.)
39 P6021A Current Probe Instruction Manual
Midband Accuracy
This test checks the midband accuracy of the probe. If the measurements are out of the specified limits in the test record, refer to
Adjustments
the
Setup
Connect a BNC-to-Dual Banana adapter to
1.
the digital multimeter (DMM) input.
Connect the Leveled Sinewave Output
2.
of the calibration generator to a BNC “T”
connector and then connect the other side
of the BNC “T” to the DMM input.
Connect the middle branch of the BNC “T”
3.
connector to the calibration fixture.
section. (See page 49.)
Performance Verification
P6021A Current Probe Instruction Manual 40
Performance Verification
Test
Set the DMM to measure AC volts, on
1.
≥2 volt range (or use Autoset).
Set the calibration generator output to
2.
@ 50 kHz, sine wave.
2V
RMS
Measure the generator output on the DMM
3.
and record the output as M1.
This voltage measurement is used to
calculate the actual test current,
Disconnect the cable at the BNC adapter
4.
attached to the DMM.
Connect the probe output to the BNC
5.
adapter attached to the DMM.
Clamp the current probe around the
6.
calibration fixture as shown. The arrow
indicator on the probe should point away
from the (+) terminal of the current source.
Set the probe to the 2 mA/mV range.
7.
Set the DMM to the 100 mV range and
8.
record the exact measurement of the DMM
as M2.
Itest
.
41 P6021A Current Probe Instruction Manual
Compute the test current and % Error
9.
using the measured amplitude values and
the formulas shown.
For example, you might measure 2.0 V for
M1, which yields a test current (
Itest
), of
40 mA.
If you then measured 20.5 mV for M2, the
computed % Error would result as shown.
Record the % Error value in the Test
10.
Record.
Set the probe to the 10 mA/mV range.
11.
Record the exact measurement of the
12.
DMM as M3.
Compute the % Error using the measured
13.
amplitude values and the formula shown.
Record the % Error value in the Test
14.
Record.
Disable the calibrator output.
15.
If the computed % Error is out of the specified
limit for either range, the probe may require an
adjustment. (See page 49,
Adjustments
.)
Performance Verification
Example:
P6021A Current Probe Instruction Manual 42
Performance Verification
Rise Time and Bandwidth
This procedure verifies that the probe meets the rise time specification by directly measuring the rise time. The high limit of the
probe bandwidth is then calculated using the measured probe rise time.
Rise Time
Connect a BNC cable to the rear-panel
1.
signal output of the calibration generator.
Connect the other end of the BNC cable to
2.
the HF current loop.
Set the generator output to a 1.0 ns rise
3.
time pulse.
Set the oscilloscope to display the entire
4.
waveform on-screen:
Vertical sensitivity to 2 mA/div
Horizontal to 20 ns/div
Trigger at 20%
Averaging on (32)
SetMeasuretoRiseTime
43 P6021A Current Probe Instruction Manual
Connect the probe to any channel (1–4).
5.
Set the probe to the 2 mA/mV range.
6.
Clamp the current probe around the HF
7.
current loop. Verify that the arrow indicator
on the probe points away from the pulse
generator.
The rise time is displayed on the
8.
oscilloscope. Record the rise time
measurement in the Test Record.
Set the probe to the 10 mA/mV range and
9.
measure the rise time. Record the rise time
measurement in the Test Record.
Bandwidth High Limit
Calculate the high frequency limit of the
10.
probe for each range setting using the
measured rise times in the formula shown:
Record the calculated bandwidth limit
11.
values in the Test Record.
Performance Verification
P6021A Current Probe Instruction Manual 44
Performance Verification
Time Constant
Setup
Connect a test lead across the + and –
1.
current output posts on the front panel of
the generator.
Clamp the probe around the test lead on
2.
the generator output.
Set the generator output to 1 A
3.
square wave.
Set the probe to the 2 mA/mV range.
4.
Set the oscilloscope to:
5.
Probe setup to current, 2X attenuation
Vertical sensitivity to 400 mA/div
Horizontal to 400 μs/div
Trigger at 50%
Averaging on (32)
Set Measure to Fall Time,
High Reference Level to 100%,
Low Reference Level to 37%
45 P6021A Current Probe Instruction Manual
RMS
,50Hz
Test
Enable the generator output.
1.
Use the oscilloscope cursors (shown in the
2.
figure) or the Fall Time Measurement to
measure the time constant (τ), beginning
from the peak of the rising edge (100%),
down to the 37% amplitude level of the
output waveform.
Record the time constant (τ)intheTest
3.
Record.
Calculate the low frequency limit of the
4.
probe bandwidth, using the time constant
in the formula shown:
Record the calculated low frequency limit
5.
valueforthe2mA/mVrangeintheTest
Record.
Performance Verification
P6021A Current Probe Instruction Manual 46
Performance Verification
Set the probe to the 10 mA/mV range.
6.
Set the oscilloscope to:
7.
Probe setup to current, 10X attenuation
Vertical sensitivity to 500 mA/div
Horizontal to 1 ms/div
Repeat steps 2 through 5 for the 10 mA/mV
8.
range.
Disable the generator output.
9.
End of procedures.
47 P6021A Current Probe Instruction Manual
Test Record
Performance Verification
Probe Model/Serial Number:
Temperature:
Date of Calibration:
Performance test
Midband accuracy (% error) 2 mA/mV -3% +3%
Rise time
Bandwidth (calculated)
High limit
Low limit
Time constant
Range Minimum Incoming
10 mA/mV -3% +3%
2mA/mV
10 mA/mV
2mA/mV
10 mA/mV
2mA/mV
10 mA/mV
2mA/mV
10 mA/mV
NA 5.8 ns
NA 5.8 ns
60 MHz NA
60 MHz NA
NA 1 kHz
NA 300 Hz
159 us NA
530 us NA
Certificate Number:
RH %:
Technician:
Outgoing
Maximum
P6021A Current Probe Instruction Manual 48
Adjustments
Adjustments
The procedures that follow describe adjustments to the probe to optimize the performance within the warranted specifications.
Midband accuracy
Aberrations
Prerequisites
Complete the
CAUTION.
handling the probe.
Performance Verification
To avoid ESD damage to the probe, use an antistatic wrist strap and work at a static-approved workstation when
procedures.
Equipment Required
Refer to the Performance Verification procedures for the equipment required. You also need a #2 flat-bladed screwdriver and an
insulated, flat-bladed adjustment tool. The tool is available from Tektronix; order part number 003-1433-00.
49 P6021A Current Probe Instruction Manual
Remove the Compensation Box Cover
Use a #2 flat-bladed screwdriver to separate the cover halves to gain access to the adjustments:
Insert the screwdriver blade into the slot
1.
and gently pry the cable cover away from
the compensation box.
Adjustments
P6021A Current Probe Instruction Manual 50
Adjustments
Use the screwdriver blade to depress each
2.
tab as you separate the cover halves.
51 P6021A Current Probe Instruction Manual
Remove the two halves and then remove
3.
the metal shield.
Adjustments
P6021A Current Probe Instruction Manual 52
Adjustments
Midband Accuracy
This procedure describes the midband accuracy adjustments for the probe. You must complete the
Performance Verification
Set the calibrator output to 2 V
1.
Set the digital multimeter (DMM) to measure AC volts,
2.
≥2.0 V range.
Set the probe to the 2 mA/mV range.
3.
Measure the output amplitude on the DMM.
4.
Adjust the 2 mA/mV control to display 20.0 mV,
5.
±0.6 mV on the DMM.
Set the probe to the 10 mA/mV range.
6.
Adjust the 10 mA/mV control to display 4.0 mV,
7.
±0.12 mV on the DMM.
Disconnect the probe from the calibrator and disable
8.
the output.
procedure before making this adjustment. Keep the test setup intact to perform the adjustment.
@50kHz.
RMS
Midband Accuracy Test
in the
53 P6021A Current Probe Instruction Manual
HF Compensation
Set up to measure rise time. (See page 43,
1.
Rise Time and Bandwidth
Set the probe to the 2 mA/mV range.
2.
Display one waveform cycle.
3.
Adjust the HF Comp control in the
4.
compensation box for the flattest response.
Adjustments
.)
P6021A Current Probe Instruction Manual 54
Adjustments
Adjust the HF control in the probe head for
5.
a balance between the best rise time and
flatness.
You may need to readjust the
NOTE.
compensation-box HF Comp adjust for optimal
rise time and flatness.
Set the probe to the 10 mA/mV range and
6.
verify performance. If necessary, adjust
the probe until risetime passes spec and
flatness is acceptable in both ranges.
55 P6021A Current Probe Instruction Manual
Maintenance
This section contains maintenance information for your probe.
Cleaning
Protect the probe from adverse weather conditions. The probe is not waterproof.
Maintenance
CAUTION.
the probe during exterior cleaning.
Do not use chemical cleaning agents; they may damage the probe. Avoid using chemicals that contain benzine, benzene,
toluene, xylene, acetone, or similar solvents.
Clean the exterior surfaces of the probe with a dry, lint-free cloth or a soft-bristle brush. If dirt remains, use a soft cloth or swab
dampened with a 75% isopropyl alcohol solution and rinse with deionized water. A swab is useful for cleaning narrow spaces on the
probe, use only enough solution to dampen the swab or cloth. Do not use abrasive compounds on any part of the probe.
P6021A Current Probe Instruction Manual 56
To prevent damage to the probe, do not expose it to sprays, liquids, or solvents. Avoid getting moisture inside
Maintenance
57 P6021A Current Probe Instruction Manual
Index
Index
A
Accessories
optional, 10
standard, 7
Adjustments, 49
Amp-second product, 18
B
Balance control, 5
Bandwidth
calculating, 43
specification, 28
Basic operation, 13
C
Cleaning, 56
Common mode noise, 16
Connect the probe, 2
Current limitations
amp-second product, 18
maximum continuous, 17
maximum pulsed, 17
D
DC gain accuracy
adjustment, 53
DC gain accuracy check, 40
Deskew
fixture, 11
Documentation, xiv
E
Equipment required
performance verification, 38
Equipment setup, 39
F
Frequency derating, 17
Functional check, 6
G
Grounding the probe, 13
I
Increasing probe sensitivity, 15
J
Jaw, 3
M
Magnetic field errors, 16
Maintenance, 56
Maximum
allowable pulse amplitude, 20
allowable pulse width, 19
continuous current rating, 17
pulsed current rating, 17
Measuring
inductance, 22
inductor turns count, 25
O
Options, 12
P6021A Current Probe Instruction Manual 58
Index
P
Performance verification, 37
Probe
maximum current limits, 17
saturation, 17
Probing principles, 15
R
Record, test, 48
Related documentation, xiv
Rise time check, 43
S
Safety Summary, v
Service
options, 12
returning the probe, xv
Slider and conductor jaw, 3
Specifications, 27
nominal, 36
typical, 29
warranted, 28
T
Test record, 48
59 P6021A Current Probe Instruction Manual
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