CT4068-NA
User Manual
Safety Summary
To avoid personal injury and/or product damage, review and comply
with the following safety precautions. These precautions apply to both
operating and maintenance personnel and must be followed during all
phases of operation, service, and repair of this instrument.
Only qualied personnel should use this probe. This differential
voltage probe is designed to be used by personnel who are trained,
experienced, or otherwise qualied to recognize hazardous situations
and who are trained in the safety precautions necessary to avoid
possible injury when using such a device.
This instrument is intended for usage within Measurement Category I
(CAT I) only.
Do not work alone when working with high voltages.
For your own safety, inspect the probe and accessories for cracks and
frayed or broken leads before each use. If defects are noted, DO NOT
USE the probe.
Hands, shoes, oor and work bench must be dry.
Avoid making measurements under humidity, dampness or other
environmental conditions that might affect safety.
The probe should be kept clean and free of any conductive
contamination.
Do not remove the probe casing. Removal of the probe’s casing may
expose you to electric shock.
Do not use the probe with its case open.
Disconnect the inputs and outputs of the probe before opening the
case.
Use only in ofce-type indoor setting
The instrument is designed to be used in ofce-type indoor
environments. Do not operate the instrument:
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z In the presence of noxious, corrosive, or flammable fumes,
gases, vapors, chemicals, or finely-divided particulates.
z In environments where there is a danger of any liquid being
spilled on the instrument.
z In air temperatures exceeding the specified operating
temperatures.
z In atmospheric pressures outside the specified altitude limits or
where the surrounding gas is not air.
Not for critical applications.
This instrument is not authorized for use in contact with the
humanbody or for use as a component in a life-support device or
system.
Hazardous voltages may be present in unexpected locations in circuitry
being tested when a fault condition in the circuit exists.
Do not substitute parts that are not approved by Cal Test Electronics or
modify this instrument. Return the instrument to Cal Test Electronics for
service and repair to ensure that safety and performance features are
maintained.
WARNING statement calls attention to an operating procedure,
A
practice, or condition, which, if not followed correctly, could result in
injury or death to personnel.
CAUTION statement calls attention to an operating procedure,
A
practice, or condition, which, if not followed correctly, could result in
damage to or destruction of parts or the entire product.
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Compliance Statements
Disposal of Old Electrical & Electronic Equipment
(Applicable in the European Union and other European countries
with separate collection systems). This product is subject to Directive
2012/19/EU of the European Parliament and the Council of the
European Union on waste electrical and electronic equipment (WEEE),
and in jurisdictions adopting that Directive, is marked as being put on
the market after August 13, 2005, and should not be disposed of as
unsorted municipal waste. Please utilize your local WEEE collection
facilities in the disposition of this product and otherwise observe all
applicable requirements.
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1 Introduction
Overview
Use the CT4068-NA 35-MHz differential probe to make safe and
accurate oating measurements with an oscilloscope. The CT4068-NA
differential probe allows conventional earth-grounded oscilloscopes
to be used for oating signal measurements of up to ±800 V for both
differential and common mode voltage.
Features
z 35 MHz bandwidth
z Selectable attenuation settings of 10x or 100x
z Up to ±800 V differential and common mode voltage
z Compatible with most oscilloscopes
z Powered by included 9 VDC mains adapter
Initial Inspection
This unit is tested prior to shipment. It is therefore ready for immediate
use upon receipt. An initial physical inspection should be made to
ensure that no damage has been sustained during shipment. After
the inspection, verify the contents of the shipment. The included
accessories for this product are:
z Two fully insulated pincer style clips (black & red)
z Two fully insulated alligator clips (black & red)
z Two 60 cm input leads (black & red)
z One 100 cm insulated BNC output cable
z One 9 V mains adapter
z User manual
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2 Product Description
Front Panel
44 mm Input
Safety Banana
Jacks
Output BNC Connection
Figure 1 Front Panel Features
Overload Indicator (Red)
Attenuation Function Switch
Power On/Off Indicator (Green)
External Power
Connection
3 Using the Probe
Getting Started
1. Connect the leads to the inputs on the probe.
2. Connect the clips to the leads.
3. Connect the probe to the oscilloscope with the BNC cable.
4. Connect the probe to the mains adapter.
5. Switch the probe from “OFF” to the desired attenuation ratio.
The power light should come on.
6. Connect the clips to the circuit to be tested.
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Vertical Scale on Oscilloscope
The actual vertical scale of the oscilloscope is equal to the
attenuation factor multiplied by the range of vertical scale selected
on the oscilloscope. For example, with the probe on factor 10x, the
oscilloscope on 0.5 V/div, the real vertical scale is 10 x 0.5 = 5 V/div.
With the probe on 100x, the real vertical scale is 100 x 0.5 = 50 V/div.
These values apply when the oscilloscope is set to 50 Ω input. When
the oscilloscope is set to 1 MΩ input, the actual vertical scale will be
halved: 2.5 V/div for the 10x probe setting and 25 V/div for the 100x
probe setting. See the chart below.
Vertical Scale on Oscilloscope
Probe
Output
Impedance
50 Ω 50 Ω 10x 0.5 V/div 5 V/div
50 Ω 50 Ω 100x 0.5 V/div 50 V/div
50 Ω 1 MΩ 10x 0.5 V/div 2.5 V/div
50 Ω 1 MΩ 100x 0.5 V/div 25 V/div
Scope Input
Impedance
Probe
Attenuation
Setting
Vertical Scale
Reading on the
Oscilloscope
Actual Vertical Scale
of the Oscilloscope
External Power Source
Power consumption of the probe is about 200 mA, thus it is not suited
for battery usage. Use the supplied adapter only. The probe may be
damaged when the input power exceeds 12 VDC.
Using a DMM
Using a DMM rather than an oscilloscope can signicantly increase
your accuracy. Use the CT2944-50 plus the CT3956 converter to use
the probe with a DMM.
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4 Cleaning
This probe does not require any particular cleaning. If necessary, clean
the case with a cloth slightly moistened with soapy water.
WARNING
Dry the probe thoroughly before attempting to make voltage
measurements.
CAUTION
Do not subject the probe to solvents or solvent fumes as these can
cause deterioration of the probe body and cables.
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5 Specications
All specications apply to the unit after a temperature stabilization time of 15 minutes over an
ambient temperature range of 25 °C ± 5 °C.
CT4068-NA Specications
Operating Parameters
Bandwidth 35 MHz
Rise Time 10 ns
Attenuation 10x/100x
Accuracy ±2%
AC CMRR -80 dB @ 60 Hz
Input Impedance Between inputs: 9 MΩ // 1.7 pF
Input Voltage
Differential Voltage (DC+ACpk) ±80 V / ±800 V
Common-Mode Voltage
(DC+ACpk)
Absolute Max Voltage
(DC+ACpk)
Output Voltage
Swing
Source Impedance (Typ.) 50 Ω
General
Power Supply External 9 VDC power supply
Power Consumption 200 mA (about 9 VDC)
Operating Temperature/
Humidity
Storage Temperature/Humidity -30°C to 70°C / 10% to 90% RH
Cable Length 100 cm (separate leads)
Input Leads Length 60 cm (separate leads)
Weight 250 g
Dimensions 195 x 55 x 30 mm
Each input to ground: 4.5 MΩ // 3.4 pF
-60 dB @ 100 Hz
-50 dB @ 1 MHz
±800 V 560 Vrms
±800 V 560 Vrms
±8 V (±4 V into 50 Ω load)
0°C to 50°C / 10% to 85% RH
Specications are subject to change without notice. To ensure the most current version of
this manual, please download the current version from our website: caltestelectronics.com.
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6 Voltage Derating Curve
The derating curve of the absolute maximum input voltage in common
mode is show as follows:
Figure 1 CT4068-NA Derating Curve
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7 Service & Warranty Information
Limited One-Year Warranty
Cal Test Electronics warrants this product to be free from defective
material or workmanship for a period of 1 year from the date of original
purchase. Under this warranty, Cal Test Electronics is limited to
repairing the defective device when returned to the factory, shipping
charges prepaid, within the warranty period.
Units returned to Cal Test Electronics that have been subject to abuse,
misuse, damage or accident, or have been connected, installed or
adjusted contrary to the instructions furnished by Cal Test Electronics,
or that have been repaired by unauthorized persons, will not be
covered by this warranty.
Cal Test Electronics reserves the right to discontinue models, change
specications, price, or design of this device at any time without notice
and without incurring any obligation whatsoever.
The purchaser agrees to assume all liabilities for any damages and/or
bodily injury which may result from the use or misuse of this device by
the purchaser, his employees, or agents.
This warranty is in lieu of all other representations or warranties
expressed or implied and no agent or representative of Cal Test
Electronics is authorized to assume any other obligation in connection
with the sale and purchase of this device.
Service
If you have a need for calibration or repair services, technical or sales
support, please contact us:
22820 Savi Ranch Parkway
Yorba Linda, CA 92887
800-572-1028 or 714-221-9330
caltestelectronics.com
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© 2017 Cal Test Electronics450858-001 Rev. A
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