Tektronix CT-1 User manual

Instructions
CT-1/CT-2
Current Transformer
070-7957-01

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 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. Tektronix will provide
such service at Customer’s site without charge during the warranty period, if the service is performed within the
normal on-site service area. Tektronix will provide on-site service outside the normal on-site service area only
upon prior agreement and subject to payment of all travel expenses by Customer. When or where on-site service is
not available, 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-1/CT-2 Current Transformer i
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.
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 With SuspectedFailures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Ground the Product. To avoid electric shock, the mounting stud must be
connected to earth ground.
Do Not Operate in Wet/DampConditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry.
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.
Symbols on the Product. The following symbols may appear on the product:
ProtectiveGround
(Earth)Terminal CAUTION Refer to Manual Double Insulated
WARNING
High Voltage
To Avoid Fire or
Personal Injury
Symbols and Terms

General Safety Summary
ii CT-1/CT-2 Current Transformer

CT-1/CT-2 Current Transformer 1
Introduction
The CT-1 and CT-2 are high-frequency, bidirectional current probes. The CT-1 is
a 1 GHz current probe and the CT-2 is a 200 MHz current probe. Each current
probe comes with a P6041 probe cable to allow you to connect directly to an
oscilloscope to make measurements.
Earth ground
mountingstud P6041 Probe
connection
Figure 1: CT-1 current probe
The CT-1 and CT-2 are available as separately purchased units (Option 09). See
the Replaceable Parts List at the end of this manual for ordering information.
This manual provides information on four subjects:
HDescription
HOperation
HSpecifications
HReplaceable Parts List

2CT-1/CT-2 Current Transformer
Description
The CT-1 (1 GHz) and CT-2 (200 MHz) are current probes designed for either
permanent or temporary installation in the device-under-test (DUT). These
probes are particularly useful for measuring high-frequency currents in solid state
circuitry with minimum circuit loading. Due to bidirectional compatibility, the
CT-1 and CT-2 can be used to inject a signal or as an interstage transformer.
The probes inductively measure current through a conductor and develop a
voltage proportional to the current. For each mA of input current, they output
5 mv (1 mv for CT-2) of signal when properly terminated. Since the CT-1 and
the CT-2 are dynamic current probes (non-DC), the presence of DC current
affects their performance. Figures 2 and 3 show the influence of DC current on
frequency response.
Frequency(Hz)
100%
90%
80%
70%
1 G10 M100 k 100 M1 M10 k
0.5 ADC 0 ADC 1 ADC
This response was obtained with the + side of the CT-1 facing
the signal source (preferred connection above 800 MHz)
Figure 2: CT-1 frequency response vs. DC current

Description
CT-1/CT-2 Current Transformer 3
100%
90%
80%
70%
60%
Frequency (Hz)
100 k 1 M10 k1 k
0.5 ADC
0 ADC 1 ADC
This response was obtained with the + side of the CT-2 facing the
signal source (preferred connection)
10 M 100 M
Figure 3: CT-2 frequency response vs. DC current
The CT-1 and CT-2 consist of a current transformer and a flexible probe
cable that attaches between the transformer and the oscilloscope. In
addition, the CT-1 and CT-2 have an internal termination resistor that
reduces reflections that allows the transformer to be disconnected from the
probe cable and left in the circuit. Figure 4 shows a simplified circuit of the
CT-1 and CT-2.
Inputcircuit 50 W
Figure 4: CT-1 and CT-2 simplifiedcircuit

4CT-1/CT-2 Current Transformer
Specifications
Table 1 lists the electrical characteristics of the CT-1 and CT-2 Transformers
when they are connected to the P6041 Probe cable. The environmental and
physical characteristics follow Tables 1 and 2.
Table 1: Electrical characteristics
Specification CT-1 with P6041 Probe CT-2 with P6041 Probe
Sensitivity
(see Figures 2 and 3) 5 mV/mA, ±3% into a 50 Wload 1 mV/mA, ±3% into a 50 Wload
PulseResponse Rise time: < 0.35 ns, 10% to 90%
Aberrations: < 5% as seen by a 1 GHz system
Rise time: < 0.5 ns, 10% to 90%
Aberrations: + 4%, –8% as seen by a
200 MHz system
L/R time constant Approximately 5 msApproximately125ms
InsertionImpedance 50 Wtermination: 1 Wshunted by approxi-
mately 5 mH
Unterminated: 2 Wshunted by approximately
5 mH
50 Wtermination: 0.04 Wshunted by
approximately 5 mH
Unterminated:0.08Wshunted by approxi-
mately 5 mH
FrequencyResponse 25 kHz to 1 GHz 1.2 kHz to 200 MHz
TurnsRatio 1:5 1:25
CapacitiveLoading #14 bare wire: typically 1.5 pF
#20 bare wire: typically 0.6 pF
#16 bare wire: typically 1.8 pF
#22 bare wire: typically 0.7 pF
Maximum Bare Wire Voltage
(uninsulated) 175 VRMS CAT I
1000 V (DC + peak AC) <3.25% duty factor
175 VRMS CAT I
1000 V (DC + peak AC) <3.25% duty factor
Signal Delay (with P6041 Probe
Cable) Approximately 2.8 ns measured from 50% points on leading edge of the current step and
outputvoltage
CT-1 Transformer only: 0.4 ns
Approximately 5.8 ns measured from 50%
points on leading edge of the current step and
outputvoltage
CT-2 Transformer only: 0.3 ns
Effect of Direct Current
(see Figures 6 and 7) Approximately0.3 ADC increases decay by a factor of 2 Approximately0.3 ADC increases decay by a factor of 2
Amp Second Rating 1 amp msec
When this product is exceeded, the core
saturates and the CT-1 output drops to zero
50 amp msec
When this product is exceeded, the core
saturates and the CT-2 output drops to zero
PulseCurrent Rating 12 amps 36 amps
RMSCurrent Rating 0.5 amperes maximum 2.5 amperes maximum
OutputConnector AmphenolSub-Minax #27-3 AmphenolSub-Minax #27-3