Cal Test Electronics CT4076-NA User manual

CT4076-NA
User Manual

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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 qualifi ed personnel should use this probe. This differential
voltage probe is designed to be used by personnel who are trained,
experienced, or otherwise qualifi ed 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, fl 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.

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Use only in offi ce-type indoor setting
The instrument is designed to be used in offi ce-type indoor
environments. Do not operate the instrument:
lIn the presence of noxious, corrosive, or flammable fumes,
gases, vapors, chemicals, or finely-divided particulates.
lIn environments where there is a danger of any liquid being
spilled on the instrument.
lIn air temperatures exceeding the specified operating
temperatures.
lIn 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 human
body 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.
A WARNING statement calls attention to an operating procedure,
practice, or condition, which, if not followed correctly, could result in
injury or death to personnel.
A CAUTION statement calls attention to an operating procedure,
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 CT4076-NA 35-MHz differential probe to make safe and
accurate fl oating measurements with an oscilloscope. The CT4076-NA
differential probe allows conventional earth-grounded oscilloscopes
to be used for fl oating signal measurements of up to ±7.5 kV for both
differential and common mode voltage.
Features
l35 MHz bandwidth
lSelectable attenuation settings of 100x or 1000x
lUp to ±7.5 kV differential and common mode voltage
lCompatible with most oscilloscopes
lPowered 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:
lTwo fully insulated pincer style clips (black & red)
lTwo fully insulated alligator clips (black & red)
lTwo 60 cm input leads (black & red)
lOne 100 cm insulated BNC output cable
lOne 9 V mains adapter
lUser manual

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2 Product Description
Front Panel
4 mm Input
Safety Banana
Jacks
Overload Indicator (Red)
Power On/Off Indicator (Green)
External Power
Connection
Output BNC Connection
Attenuation Function Switch
Figure 1 Front Panel Features
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 100x, the
oscilloscope on 0.5 V/div, the real vertical scale is 100 x 0.5 = 50 V/
div. With the probe on 1000x, the real vertical scale is 1000 x 0.5 = 500
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: 25 V/div for the 100x probe setting and 250 V/div for the
1000x probe setting. See the chart below.
Vertical Scale on Oscilloscope
Probe
Output
Impedance
Scope Input
Impedance
Probe
Attenuation
Setting
Vertical Scale
Reading on the
Oscilloscope
Actual Vertical Scale
of the Oscilloscope
50 Ω 50 Ω 10x 0.5 V/div 50 V/div
50 Ω 50 Ω 1000x 0.5 V/div 500 V/div
50 Ω 1 MΩ 10x 0.5 V/div 25 V/div
50 Ω 1 MΩ 1000x 0.5 V/div 250 V/div
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. CAUTION: The probe
may be damaged when the input power exceeds 12 VDC.
Using a DMM
Using a DMM rather than an oscilloscope can signifi cantly 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 Specifi cations
All specifi cations apply to the unit after a temperature stabilization time of 15 minutes over an
ambient temperature range of 25 °C ± 5 °C.
CT4076-NA Specifi cations
Operating Parameters
Bandwidth 35 MHz
Rise Time 10 ns
Attenuation 100x / 1000x
Accuracy ±2%
AC CMRR -80 dB @ 60 Hz
-60 dB @ 100 Hz
-50 dB @ 1 MHz
Input Impedance Between inputs: 50 MΩ // 1.3 pF
Each input to ground: 25 MΩ // 2.6 pF
Input Voltage
Differential Voltage (DC+ACpk) ±750 V / ±7.5 kV
Common-Mode Voltage
(DC+ACpk)
±7.5 kV or 5.5 kVrms
Absolute Max Voltage
(DC+ACpk)
±7.5 kV or 5.5 kVrms
Output Voltage
Swing ±8 V (±4 V into 50 Ω load)
Source Impedance 50 Ω
General
Power Supply External 9 VDC power supply
Power Consumption 200 mA about (9 VDC)
Operating Temperature/
Humidity
0°C to 50°C / 10% to 85% RH
Storage Temperature/Humidity -30°C to 70°C / 10% to 90% RH
Cable Length 100 cm
Input Leads Length 60 cm each
Weight 350 g
Dimensions 220 x 85 x 30 mm
Specifi cations 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. CT4076-NA Derating Curve