GW Instek GVT-427B User Manual

GVT-427B User Manual

Contents Page

Safety Terms and Symbols………………………. 1

Introduction………………………………………. 4

Preliminary Notes………………………………… 5

Panel Description…………………………………. 6

Operation Method………………….…………….. 10

Specifications…………………………………… 13

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Maintenance………………………………………. 16 Cleaning……………………………………… 16

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Troubleshooting……………………………… 16

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Interchangeable Parts……………………………. 17

GVT-427B User Manual

SAFETY TERMS AND SYMBOLS

These terms may appear in this manual or on the product:

WARNING. Warning statements identify condition 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.

The following symbols may appear in this manual or on the product:

DANGER High Voltage

ATTENTION refer to Manual

Protective Conductor Terminal

(Ground) Earth Terminal

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GVT-427B User Manual

FOR UNITED KINGDOM ONLY

NOTE: This lead/appliance must only be wired by competent persons

WARNING: THIS APPLIANCE MUST BE EARTHED

IMPORTANT: The wires in this lead are coloured in accordance with the following code:

Green/ Yellow: Earth

Blue:	Neutral
Brown:	Live (Phase)

As the colours of the wires in main leads may not correspond with the colours marking identified in your plug/appliance, proceed as follows:

The wire which is coloured Green & Yellow must be connected to the Earth terminal marked with the letter E or by the earth

symbol or coloured Green or Green & Yellow.

The wire which is coloured Blue must be connected to the terminal which is marked with the letter N or coloured Blue or Black.

The wire which is coloured Brown must be connected to the terminal marked with the letter L or P or coloured Brown or Red.

If in doubt, consult the instructions provided with the equipment or contact the supplier.

This cable/appliance should be protected by a suitably rated and approved HBC mains fuse : refer to the rating information on the equipment and/or user instructions for details. As a guide, cable

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GVT-427B User Manual

of 0.75mm² should be protected by a 3A or 5A fuse. Larger conductors would normally require 13A types, depending on the connection method used.

Any moulded mains connector that requires removal /replacement must be destroyed by removal of any fuse & fuse carrier and disposed of immediately, as a plug with bared wires is hazardous if a engaged in live socket. Any re-wiring must be carried out in accordance with the information detailed on this label.

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GVT-427B User Manual

Introduction

GVT-427B is versatile AC voltmeter which is able to measure AC voltage from ranges of 10 Hz to 1 MHz with full scale ranges from 300 µV to 100 V. The dB scale measures 1V as 0dB and ranges from -90 dB to +41 dB. The 600 Ω (1mW) dBm scale ranges from -90 dBm to +43 dBm.

The scales on the meter are graduated up to 1.1 (for +1dB) and these extended scales are especially useful when measuring the characteristics of audio amplifiers. In addition, both instruments can give AC voltage output of approximately 0.1V in full scale from the output terminals, and the measurements can therefore be monitored.

GVT-427B is a two channels voltmeter with isolated output for each channel which enables it to be used as a two channels preamplifier.

GVT-427B User Manual

Preliminary Notes

1.Chassis grounding terminal:

Make sure the chassis ground terminal is connected to the earth before inserting the power plug into the main supply.

2.Maximum input voltage:

The voltmeter may be damaged if any input voltage exceeding the specified voltage is applied to it. The specified voltage is determined by adding the peak value of the input signal and the superimposed DC voltage: 300 V for the 300 µV ranges, and 500 V for the 3 V to 100 V ranges.

3.Connection leads:

When the measured signal level is low (i.e. 300 µV) or the measured signal source impedance is high, the input line is susceptible to external noise. To resist the noise, shielded wires or a coaxial cable should be used depending on the noise frequency.

4.Full scales:

GVT millivoltmeter adopts a special extended scale which has a reading range larger than the conventional full scale.

Conventional				Extended
0	to	1.0		0	to	1.12
0	to	3.1	(3.2)	0	to	3.5
-20	to	0 dB		-20	to +1 dB
-20	to +2 dBm			-20	to +3.2 dBm

Note that the term “full scale” considers ‘1.0’ on the 0 - 1.12 scales as the rated value. The red ▼ mark is setting at ‘1.0’ on the outermost scale.

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