Tektronix TCP202 User manual

Instruction Manual
TCP202
15 Ampere AC/DC Current Probe
070-9542-00

Copyright Tektronix, Inc. All rights reserved.
Tektronix products are covered by U.S. and foreign patents, issued and
pending. Information in this publication supercedes that in all previously
published material. Specifications and price change privileges reserved.
Printed in the U.S.A.
Tektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000
TEKTRONIX, TEK, and TekProbe are registered trademarks of Tektronix, Inc.

WARRANTY
Tektronix warrants that the products that it manufactures and sells will be free from defects
in materials and workmanship for a period of one (1) year from the date of purchase from
an authorized Tektronix distributor. 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. Batteries are excluded from this warranty.
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, shipping charges prepaid,
and with a copy of customer proof of purchase. 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
LISTED PRODUCTS 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.

TCP202 Instruction Manual i
Table of Contents
General Safety Summary iii. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Getting Started 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features and Accessories 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compensating the Probe (Optional) 4. . . . . . . . . . . . . . . . . . . . .
Operating Basics 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measurement Limits 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Degaussing and Balancing the Probe 6. . . . . . . . . . . . . . . . . . . .
Measurement Procedures and Techniques 7. . . . . . . . . . . . . . . . .
Reference 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Measurements 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inductance Measurements 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuity Test of Multiple-Conductor Cable 18. . . . . . . . . . . . . .
Measuring Inductor Turns Count 18. . . . . . . . . . . . . . . . . . . . . . . .
Specifications 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warranted Characteristics 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Characteristics 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nominal Characteristics 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning the Probe Head 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing the Compensation Box 30. . . . . . . . . . . . . . . . . . . . . . .
Probe Head Disassembly 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Obtaining Replacement Parts 38. . . . . . . . . . . . . . . . . . . . . . . . . .
Preparation for Shipment 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Verification and Adjustment 40. . . . . . . . . . . . . .
Test Procedure Conditions 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Required 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Accuracy 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bandwidth 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rise Time 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Calibrator Accuracy (Optional) 43. . . . . . . . . . . . . . . . . . . . . . . . .
Replaceable Parts 44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents
ii TCP202 Instruction Manual
List of Figures
Figure 1: TCP202 Current Probe 1. . . . . . . . . . . . . . . . . . . . . . . .
Figure 2: Coarse Balance Adjustment 3. . . . . . . . . . . . . . . . . . . .
Figure 3: Connecting the Calibrator 4. . . . . . . . . . . . . . . . . . . . .
Figure 4: Polarity of Current Flow 8. . . . . . . . . . . . . . . . . . . . . .
Figure 5: Measuring Differential Current and Nulls 9. . . . . . . . .
Figure 6: Increasing the DC Measurement Range 11. . . . . . . . . . .
Figure 7: Increasing Probe Sensitivity 12. . . . . . . . . . . . . . . . . . . .
Figure 8: Measuring Inductance with a Low-Impedance
Source 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 9: Linear Current versus Time Ramp 16. . . . . . . . . . . . . . .
Figure 10: Measuring Inductance with a High-Impedance
Source 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 11: High-Impedance Source Current Ramp 17. . . . . . . . . .
Figure 12: Measuring the Number of Turns in a Coil 19. . . . . . . .
Figure 13: Turns Measurement Using Reference Coil 19. . . . . . .
Figure 14: Frequency Derating 23. . . . . . . . . . . . . . . . . . . . . . . . .
Figure 15: Insertion Impedance – Magnitude –
Single Conductor 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 16: Insertion Impedance – Phase Angle –
Single Conductor 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 17: Insertion Impedance – Magnitude –
10-Turn #24 AWG Primary 25. . . . . . . . . . . . . . . . . . . . . . . . .
Figure 18: Insertion Impedance – Phase Angle –
10-Turn #24 AWG Primary 26. . . . . . . . . . . . . . . . . . . . . . . . .
Figure 19: Current Ratings 27. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 20: Replacing TekProbe Interface Pins 30. . . . . . . . . . . . .
Figure 21: Replacing the TekProbe collar 31. . . . . . . . . . . . . . . . .
Figure 22: Removing the Compensation Box Covers 32. . . . . . . .
Figure 23: Accessing the Gain Adjustment 33. . . . . . . . . . . . . . . .
Figure 24: Replacing the Compensation Box Cover 34. . . . . . . . .
Figure 25: Removing the Strain Relief Boot 35. . . . . . . . . . . . . . .
Figure 26: Removing the Top Half of the Probe 36. . . . . . . . . . . .
Figure 27: Removing the Probe Slide 37. . . . . . . . . . . . . . . . . . . .
Figure 28: Removing the Current Transformer 38. . . . . . . . . . . . .
Figure 29: TCP202 and Replaceable Accessories 46. . . . . . . . . . .
Figure 30: Replaceable Parts – Compensation Box 48. . . . . . . . .
Figure 31: TCP202 Optional Accessories 50. . . . . . . . . . . . . . . . .

TCP202 Instruction Manual iii
General Safety Summary
Review the following safety precautions to avoid injury and prevent
damage to this product or any products connected to it.
Injury Precautions
Do Not Operate in Wet/Damp Conditions. To avoid electric shock, do not
operate this product in wet or damp conditions.
Do Not Operate in an Explosive Atmosphere. To avoid injury or fire
hazard, do not operate this product in an explosive atmosphere.
Observe Maximum Working Voltage. Do not use this product on bare
wires above 300 V (DC + peak AC).
Product Damage Precautions
Do Not Drop the Probe Head. The probe head contains fragile
components that can be damaged by a high impact. Take care to
prevent the probe head from dropping on the floor or other hard
surface. Secure the probe head in a safe location when not in use.
Do Not Operate With Suspected Failures. If you suspect there is damage
to this product, have it inspected by qualified service personnel.
Do Not Immerse in Liquids. Clean the probe using only a damp cloth.
Refer to cleaning instructions.
Safety Terms and Symbols
Terms in This Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that
could result in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that
could result in damage to this product or other property.

General Safety Summary
iv TCP202 Instruction Manual
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.
Symbols on the Product. These symbols may appear on the product:
ProtectiveGround
(Earth)Terminal ATTENTION Refer to Manual Double Insulated
DANGER
High Voltage
Certifications and Compliances
Refer to the specifications section for a listing of certifications and
compliances that apply to this product.

TCP202 Instruction Manual 1
Getting Started
This section describes the TCP202 Current Probe and gives
instructions on how to install and functionally test the probe.
Features and Accessories
The TCP202 Current Probe (Figure 1) is a 50 MHz current probe for
use with Tektronix oscilloscopes that have the TekProbe interface.
The probe can measure up to 15 A (DC + peak AC).
Figure 1: TCP202 Current Probe

Getting Started
2TCP202 Instruction Manual
Probe Head. The probe head contains a Hall Effect
device for measuring current. The jaw of the probe
clamps on any wire (including insulation) that is less
than or equal to 3.8 mm (0.15 inches) in diameter.
TekProbe Interface. The TekProbe interface provides
power, signal, and probe characteristic data.
If your oscilloscope does not support the TekProbe
interface, you can use the optional 1103 probe power
supply as an effective interface. Contact your local
Tektronix representative for more information.
Degauss. The degauss button removes residual
magnetism from the probe core that would otherwise
cause measurement errors.
Balance Thumbwheel. The balance thumbwheel
compensates for minor DC offsets of the probe output.
Coarse Balance Adjustment. The coarse balance
adjustment centers the range of the balance thumb-
wheel. Use this adjustment only if the thumbwheel
does not have enough range.
Calibrator (optional). With some TDS oscilloscopes, you
can compensate the probe for maximum accuracy using
the optional calibrator. Use the calibrator only if your
oscilloscope displays the Asymbol when the current
probe is connected. (For ordering information, see
Replaceable Parts starting on page 44.)

Getting Started
TCP202 Instruction Manual 3
Installation
Install the TCP202 Current Probe as follows:
1. Set the input channel to a zero reference point.
2. Connect the output of the probe to the TekProbe interface of the
oscilloscope or other measurement instrument. The measurement
instrument input must have a ground reference.
If your TDS oscilloscope does not display amperes/division, interpret
volts/division as amperes/division.
If you are using the 1103 TekProbe Power Supply, you must set the
oscilloscope input coupling to DC and the input impedance to 50 
Interpret V/division as 10 A/division. For example, interpret
100 mV/division as 1 A/division.
3. With the probe jaw empty, push the slide on the probe until it
locks in the CLOSED position.
4. Press the DEGAUSS button.
5. Balance the probe as follows:
a. Set the oscilloscope vertical scale to 10 mA/division.
b. Open and close the probe jaw.
c. Adjust the BALANCE thumbwheel until the displayed
signal is zero.
6. If you cannot zero the display as described in step 5c, use the
coarse balance adjustment (Figure 2) to center the range of the
thumbwheel.
Coarse balance
Figure 2: Coarse Balance Adjustment

Getting Started
4TCP202 Instruction Manual
Compensating the Probe (Optional)
With some TDS oscilloscopes, you can compensate the probe for
maximum accuracy using the optional calibrator. Perform this
procedure only if your oscilloscope displays the Asymbol when
you connect the probe output to the oscilloscope input.
1. To connect the calibrator, press the release button (Figure 3) and
connect the calibrator to the probe compensation output of the
oscilloscope.
Release button
Figure 3: Connecting the Calibrator
2. Close and lock the probe jaw over the calibrator loop.
3. Adjust the oscilloscope to display the signal.
4. Press VERTICAL MENUCal ProbeOK Compensate Gain.
If the probe passes the compensation routine, the probe is accurate to
within ±1% from 50 mA to 5 A and ±2% from 5 A to 15 A.
If the probe fails the compensation routine, refer to the procedure for
checking the DC accuracy of the probe on page 41 and the procedure
for accessing the internal gain adjustment on page 32.
Repeat this procedure whenever you move the current probe to
another input.

TCP202 Instruction Manual 5
Operating Basics
This section contains important precautions and techniques for
clamping the probe on a circuit and taking basic measurements.
Measurement Limits
Before you clamp the probe on a circuit to measure current, observe
the precautions for uninsulated wires and the maximum current
ratings.
Precautions for Uninsulated Conductors
WARNING. To avoid electrical shock from uninsulated conductors,
observe the following precautions:
Disconnect the power to the uninsulated conductor before inserting
the conductor in or removing the conductor from the probe jaw.
Do not apply a voltage higher than 300 V (DC + peak AC) between
earth ground and an uninsulated conductor that is in the probe jaw.
Maximum Current Rating
There are two basic current ratings: maximum peak current and
maximum continuous current. In addition, the maximum peak
current is limited by the A/second rating. For a graph of these limits,
refer to Figure 19 on page 27.
The maximum peak current is 50 A with a pulse width ≤10 ms
(500 mAseconds). This 500 mAseconds rating applies to any peak
current over 15 A. The product of the peak current and pulse width
(at 50% of peak) must be 500 mAseconds or less. For example, the
maximum pulse width is 20 ms for a pulse of 25 A peak.

Operating Basics
6TCP202 Instruction Manual
The maximum continuous current that this probe can measure is
15 A (DC + peak AC). This limit derates with frequency; as the
frequency increases, the maximum current rating decreases. For a
graph of this relationship, see Figure 14 on page 23.
Multiple Current Probes
Up to four TCP202 current probes may be used simultaneously on
one TDS Series oscilloscope if the total in-phase current measured
by all of the probes does not exceed 40 amperes. Above 40 amperes,
the TekProbe interface may overload and cause measurement or
display errors.
When one or two TCP202 current probes are used on a TDS Series
oscilloscope, the ratings are as shown in Figure 19 on page 27.
Degaussing and Balancing the Probe
For accurate measurements, you must occasionally degauss and
balance the probe. Degaussing removes residual magnetization from
the probe core that would otherwise shift the zero point and cause
measurement errors. Balancing the probe compensates for any DC
offset that remains on the probe output after degaussing.
Degauss and balance your probe in each of the following cases:
HAfter turning on the oscilloscope and allowing a 20-minute
warm-up period
HWhenever an overload condition occurs
HWhenever the probe is subjected to a strong external magnetic
field
HWhenever there is a measurable DC offset that does not come
from the conductor under test
To degauss and balance the probe, follow the installation procedure
on page 3.
You may degauss the probe with a conductor in the jaw if you first
disconnect the power to the conductor. This technique compensates
for any offsets caused by stray DC magnetic fields around the circuit
under test.

Operating Basics
TCP202 Instruction Manual 7
CAUTION. While degauss occurs, the probe will induce a small
voltage in the unpowered circuit (33 mV in series with 1.5 M). Your
circuit must be able to absorb this induced voltage. With low
impedance circuits, several amperes may be induced in the circuit
being measured. This may be of concern if you are using very small
conductors.
Measurement Procedures and Techniques
This section presents procedures and techniques for basic current
measurements.
BasicProcedure
Measure AC or DC current in a single conductor as follows:
1. Observe the safety precautions and operating limits.
2. If necessary, degauss and balance the probe.
3. Close and lock the probe jaw over the conductor. Conventional
current flows from positive to negative. For the correct polarity
reading, connect the probe so that the current flow, from positive
to negative, is aligned with the arrow on the probe jaw (see
Figure 4).
4. Read the measurement. Adjust the display of the measurement
instrument as necessary.
5. If necessary, adjust the oscilloscope offset control to offset a DC
level. (AC coupling is automatically disabled on TDS oscillo-
scopes when the probe is connected.)

Operating Basics
8TCP202 Instruction Manual
Figure 4: Polarity of Current Flow
Measuring Differential Current
You can place two conductors in a current probe to provide a
differential or null current measurement. This avoids the necessity of
using two current measurement systems with a differential
oscilloscope amplifier.
1. Orient the two conductors under test so that the polarities oppose
each other. Clamp the current probe around the two conductors as
shown in Figure 5.
2. Measure the current. A waveform above the baseline indicates
the conductor with the conventional current flow in the direction
of the probe arrow is carrying the greater current.
3. To adjust for a current null, adjust the current in one of the
conductors until the displayed measurement is zero.

Operating Basics
TCP202 Instruction Manual 9
Conductor 2
Current probe
Conductor 1
Current
Current
Figure 5: Measuring Differential Current and Nulls

Operating Basics
10 TCP202 Instruction Manual
Extending the DC Current Range
You may encounter situations where your measurement exceeds the
maximum current rating of the connected probe. This section
discusses methods for extending DC current ranges without
exceeding specified limits.
WARNING. To avoid personal injury or equipment damage, do not
exceed the specified electrical limits of the oscilloscope or any
applicable accessories. When using multiple conductors, do not
exceed current limits on either conductor.
If you want to measure a low-amplitude AC component that is
superimposed on an extremely large steady state DC component
(such as in a power supply), or if you want to extend the DC current
range of your probe, you can add offset (bucking) current with a
second conductor.
By adding bucking current, the amount of DC current that you
measure is the difference between the DC component of the signal
and the bucking current. You can then calculate the amount of DC
current in the conductor under test by adding the value of the
measured current to the value of the bucking current.
To supply additional bucking current, place a second conductor that
has a pure DC component of known value in the probe jaw with the
conductor under test, as shown in Figure 6(a) on page 11. Orient the
second conductor so that the bucking current flows in the opposite
direction of the DC flow in the conductor under test.
You can increase the value of the bucking current by winding
multiple turns of the second conductor around the probe, as shown in
Figure 6(b) on page 11. The bucking current is equal to the current
flowing in the conductor, multiplied by the number of turns wound
around the probe. For example, if the second conductor has a current
of 100 mA DC and is wrapped around the probe five times, the DC
bucking current is 100 mA multiplied by 5, or 500 mA DC.

Operating Basics
TCP202 Instruction Manual 11
NOTE. Adding a second conductor to the probe reduces the upper
bandwidth limit of the probe.
Conductor
under test
Second conductor
suppling bucking
current
Extra turns added
to increase
bucking current
Conductor
under test
Current
Current
(a) Adding a second conductor
(b) Adding multiple turns
Current
Current
Current probe
Current probe
Figure 6: Increasing the DC Measurement Range

Operating Basics
12 TCP202 Instruction Manual
Increasing Measurement Sensitivity
If you are measuring DC or low-frequency AC signals of very small
amplitudes, you can increase measurement sensitivity of your
Current Probe by winding several turns of the conductor under test
around the probe as shown in Figure 7. The signal is multiplied by
the number of turns around the probe.
When viewing the signal on the oscilloscope screen, divide the
displayed amplitude by the number of turns to obtain the actual
current value. For example, if a conductor is wrapped around the
probe five times and the oscilloscope shows a reading of 50 mA DC,
the actual current flow is 50 mA divided by 5, or 10 mA DC.
NOTE. Winding multiple turns around the probe increases the
insertion impedance of the probe which can affect the accuracy of
your measurements and the circuit under test. For graphs of insertion
impedance, refer to figures 15 and 17 on page 23.
Extra turns for
increased sensitivity
Conductor
under test
Current probe
Figure 7: Increasing Probe Sensitivity