Tektronix CT-6 User manual

Instruction Manual
CT-6
High Frequency AC Current Probe
071-0453-00

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.
Tektronix Inc., P.O. Box 500, Beaverton, OR. 97077
TEKTRONIX and TEK 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 shipment. If a
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.
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 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.

CT-6 Instruction Manual i
Table of Contents
General Safety Summary v. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contacting Tektronix vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Getting Started 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessories and Options 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Accessories 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Options 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Accessories 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Holder 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evaluation Board (Optional) 8. . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Basics 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interpreting the Current and Voltage Ratings 9. . . . . . . . . . . . . .
Matching Impedances 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measuring Current 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Injecting Current Signals 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optimizing Performance at High Frequencies 13. . . . . . . . . . . . .
Circuit Equivalent 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting the Wire Size and Length 14. . . . . . . . . . . . . . . . . . .
Positioning the Probe 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ground Side and Signal Side Measurements 16. . . . . . . . . . . . . . .
Using the Optional Evaluation Board 17. . . . . . . . . . . . . . . . . . . .
Calibration Lines 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evaluation Lines 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe Holder 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Verification 25. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Required 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preparation 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mount the Current Probe on the Evaluation Board 26. . . . . . .
Frequency Response and Sensitivity 27. . . . . . . . . . . . . . . . . . . . .
Set up the Signal Generator with the Digital Oscilloscope 27.
Measure Output and Calculate Sensitivity 27. . . . . . . . . . . . . .
Measure Low End Frequency Response 27. . . . . . . . . . . . . . .
Measure High End Frequency Response 28. . . . . . . . . . . . . . .
CT-6 Test Record 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents
ii CT-6 Instruction Manual
Frequency Response and Sensitivity – Alternate Procedure 30. . .
Set up the Network Analyzer 30. . . . . . . . . . . . . . . . . . . . . . . .
Calibrate Network Analyzer with Evaluation Board 31. . . . . .
Calibrate out Line Losses 31. . . . . . . . . . . . . . . . . . . . . . . . . . .
Remove Delay 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Verify Frequency Response and Sensitivity 32. . . . . . . . . . . .
CT-6 Test Record – Alternate Procedure 33. . . . . . . . . . . . . . . . . .

Table of Contents
CT-6 Instruction Manual iii
List of Figures
Figure 1: CT-6 current probe with probe holder and
BNC-SMA adapter 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 2: Using a single wire 5. . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 3: Using two wires to measure differential
current 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 4: Using a square pin and jumper 6. . . . . . . . . . . . . . .
Figure 5: Securing the CT-6 probe head to a test fixture
board 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 6: Signal measurement 11. . . . . . . . . . . . . . . . . . . . . . . .
Figure 7: Signal injection 12. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 8: Circuit equivalent of added inductance and
capacitance 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 9: Positioning for best HF response
(20–25 gauge) 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 10: Coupling the probe to signal side or
ground side 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 11: Test Fixture board for the CT-6 current
probe 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 12: Securing the CT-6 probe head to the test
fixture board 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 13: Typical frequency response (Bode plot) 22. . . . . . .
Figure 14: Typical group delay (df/df) 22. . . . . . . . . . . . . . . . .
Figure 15: Securing the current probe to the evaluation
board 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents
iv CT-6 Instruction Manual

CT-6 Instruction Manual v
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.
To Avoid Fire or Personal Injury
Connect and Disconnect Properly. Do not connect or disconnect probes
or test leads while they are connected to a voltage source.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe all
ratings and markings on the product. Consult the product manual for
further ratings information before making connections to the product.
Do Not Operate Without Covers. Do not operate this product with
covers or panels removed.
Do Not Operate With Suspected Failures. If you suspect there is damage
to this product, have it inspected by qualified service personnel.
Do Not Operate in Wet/Damp Conditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry.

General Safety Summary
vi CT-6 Instruction Manual
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.
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:
CAUTION
Refer to Manual Double
Insulated ProtectiveGround
(Earth) Terminal

CT-6 Instruction Manual vii
Contacting Tektronix
Product
Support For application-oriented questions about a Tektronix measurement product, call toll free in North
America:
1-800-TEK-WIDE (1-800-835-9433 ext. 2400)
6:00 a.m. – 5:00 p.m. Pacific time
Or contact us by e-mail:
[e-mail]
For product support outside of North America,
contact your local Tektronix distributor or sales
office.
Service
Support Contact your local Tektronix distributor or sales office. Or visit our web site for a listing of
worldwide service locations.
http://www.tektronix.com
For other
information In North America: 1-800-TEK-WIDE (1-800-835-9433)
An operator will direct your call.
To write us Tektronix, Inc.
P.O. Box 500
Beaverton, OR 97077

Contacting Tektronix
viii CT-6 Instruction Manual

CT-6 Instruction Manual 1
Getting Started
The CT-6 is a miniature AC current probe suited for probing
low-voltage, high-frequency circuits. Performance highlights include
the following:
H250 kHz to 2 GHz typical bandwidth
H5 mV/mA sensitivity
Hlow insertion impedance
Hinductive pick up or injection of signals
For a complete list of specifications, see page 21.
Figure 1: CT-6 current probe with probe holder and BNC-SMA adapter

Getting Started
2CT-6 Instruction Manual
Accessories and Options
Standard accessories accompany every CT-6 current probe. Both
standard and optional accessories may be ordered separately. Options
must be ordered at the time of purchase.
StandardAccessories
The following accessories ship with every CT-6 current probe:
HInstruction Manual (071-0453-00)
HBNC-SMA adapter (015-0572-00)
HProbe holder (015-0682-00) with 2-56 screws (211-0034-00)
HMarker bands for identifying multiple probes on the inputs of a
test instrument (016-1315-00)
HCertificate of traceable calibration
Options
The following CT-6 options are available at the time of purchase:
HOption C3 (three years calibration services)
HOption D1 (calibration data)
HOption D3 (three years calibration data)
HOption R3 (extended 3-year repair/service contract)
HOption TF (evaluation board included with the current probe)
OptionalAccessories
The following optional accessories are recommended for the CT-6
current probe:
HEvaluation board without the current probe (067-0349-00)
HSMA–SMA barrel adapter (015-1012-00)

Getting Started
CT-6 Instruction Manual 3
Installation
Install the probe on the measurement instrument and in the circuit as
detailed in this section.
To measure or inject a signal using the CT-6 current probe, do these
steps:
1. Connect the SMA output connector of the CT-6 current probe to
the measurement instrument, or to the signal generator if
injecting a signal. Use the SMA-BNC adapter if necessary. Make
sure the instrument or signal generator has a 50 Wimpedance.
WARNING. To avoid personal injury, use the probe on grounded
systems only. To avoid RF burn hazard, apply stimulus signal only
after connecting the probe to the circuit.
2. Power off the circuit under test.
3. Choose the point in the circuit where you are going to measure
current or inject a signal.
WARNING. To avoid personal injury or fire, do not exceed the
maximum bare wire voltage of 30 V. Avoid using the probe in circuits
where voltages exceed 30 V.
Maintain adequate spacing between the housing on the probe head
and other exposed circuit connections. The hole in the probe head is
insulated, but the painted housing on the probe head is at ground
potential.
4. Interrupt the circuit under test and route a conductor through the
hole in the probe head in one of the following ways:
a. For the best overall signal fidelity, use a short wire with a
small diameter. (See Figure 2.)
b. For convenience in measuring signals below 1 GHz you
can use a square pin and jumper. (See Figure 4.)

Getting Started
4CT-6 Instruction Manual
c. For measuring the difference between two signal currents,
use two wires with opposing polarities. (See Figure 3.)
Fine, thinly insulated wire such as transformer wire is best
for this application.
5. To fixture the probe in place, use the accessory probe holder. See
page 7.
6. Reconnect the interrupted circuit keeping the lead length as short
as possible. To avoid applying too much heat with the soldering
iron, do these steps:
a. Solder one end of the wire to the positive (+) polarity side
the interrupted circuit under test.
b. Insert the wire into the current probe.
c. Solder the other end of the wire on the polarity dot side of
current probe. Use just enough heat to temporarily tack the
wire in place.
7. Power on the circuit under test and measure or inject the signal.
Stay within the ratings of the probe.
For information on the ratings of the probe and on how to optimize
performance, refer to Operating Basics on page 9 and Specifications
on page 21.

Getting Started
CT-6 Instruction Manual 5
Observe polarity of circuit, use short
wire, keep probe head close to the
circuit board
Polarity dot
Position probe head
to optimize signal
fidelity
Figure 2: Using a single wire

Getting Started
6CT-6 Instruction Manual
Transformer wire, 26
gauge or smaller
idiff +i2*i1
Figure 3: Using two wires to measure differential current
Polarity dot
Jumper
NOTE: This type of connection is not
suitable for frequencies above 1 GHz.
Figure 4: Using a square pin and jumper

Getting Started
CT-6 Instruction Manual 7
Probe Holder
To help stabilize the probe, you can use the probe holder provided to
secure the probe to a test fixture or prototype circuit board. See
Figure 5.
Probe holder
Horizontal Vertical
Figure 5: Securing the CT-6 probe head to a test fixture board
To mount the probe holder, do these steps:
1. Temporarily place the probe and probe holder in the position you
intend to mount them.
2. Use the probe holder to mark holes on the test fixture or
prototype board.
3. Drill holes that are the appropriate diameter for the mounting
hardware you intend to use. The 2-56 screws and probe holder
supplied with the current probe are designed to mount in plated

Getting Started
8CT-6 Instruction Manual
circuit board holes that are 0.080 inches in diameter and 0.360
inches center to center.
Evaluation Board (Optional)
Prepare the optional evaluation board for use by installing the five
rubber feet with the screws provided; install one foot at each corner
of the board and one in the middle.