Tektronix 305 DMM Instruction Manual

Tfektronix

305 DMM

OSCILLOSCOPE

OPERATORS

INSTRUCTION MANUAL

Tektronix. Inc.

P.0. Box 500
Beaverton. Oregon 97077

070-2424-00

Tektronix

COMMITTED TO EXCELLENCE

PLEASE CHECK FOR CHANGE
INFORMATION AT THE REAR

OF THIS MANUAL

305 DMM

OSCILLOSCOPE

OPERATORS

INSTRUCTION MANUAL

First Printing JUL 1978

Serial Number

-----------------------------

Revised JUL 1981

Copyright e 1978 Tektronix, Inc. All rights
reserved. Contents of this publication may not be
reproduced in any form without the written
permission of Tektronix, Inc.

Products of Tektronix, Inc. and its subsidiaries
are covered by U.S. and foreign patents and/or
pending patents.

TEKTRONIX, TEK. SCOPE-MOBILE, andf^?*
are registered trademarks of Tektronix, Inc.
TELEQUIPMENT is a registered trademark of
Tektronix U.K Limited.

Printed in U.S A. Specification and price change
privileges are reserved.

TABLE OF CONTENTS

Page

Page

LIST OF ILLUSTRATIONS ii
LIST OF TABLES

iii

GENERAL INFORMATION

1

ADJUSTMENT AND BASIC DISPLAY

17

Introduction

1

Oscilloscope Display

17

Safety Information

1

Digital Multimeter Display

20

Operating Voltage

2

APPLICATION AND MEASUREMENTS

22

Internal Battery Operation

4

Battery Charging

5

Instantaneous Amplitude Measurements-DC

22

Battery Care

5

Peak-to-Peak Amplitude Measurement-AC

24

Voltage Comparison Measurements

25

CONTROLS AND CONNECTORS

6

Time Duration And Frequency Measurement

20

Power Source And Connectors

6

Time Difference Measurement Between Two

Calibrator And Display Controls 8

Pulse Waveforms From Different Sources

27

Vertical Controls 8

Dual Trace Phase Difference Measurements

28

Horizontal Controls

11

High Resolution Phase Difference Measurement

30

Triggering And Sweep Controls 12

Rise Time Measurement

31

Digital Multimeter Controls

14

Common Mode Rejection

32

BASIC INSTRUMENT OPERATION

15

SPECIFICATION

33

Operating Considerations 15

Electrical Characteristics

33

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305 Operators

LIST OF ILLUSTRATIONS

Page

Page

Figure 1. Description of power source operation.

3

Figure 13. Example of peaktopeak voltage

Figure 2. View of rear cover.

6

measurement.

24

Figure 3.

Right side view of instrument cabinet. 7 Figure 14. Example of time duration and frequency

Figure 4. Left side view of instrument cabinet.

7 measurement

26

Figure 5. Location of display and calibrator controls.

9

Figure 15. Time difference between two pulses from

Figure 6. Location o f vertical deflection system

different sources. 27

controls. 10

Figure 16. Example of dual trace phase difference

Figure 7. Location of horizontal deflection system measurement. 28

controls.

11

Figure 17. Example of high resolution phase difference

Figure 8.

Location of trigger and sweep controls.

12

measurement. 30

Figure 9. Location of digital multimeter controls.

14

Figure 18. Example of rise time measurement. 31

Figure 10. Probe compensation.

16

Figure 19. Common mode rejection of an undesired

Figure 11.

Location of external operator adjustments.

19

line frequency.

32

Figure 12. Example of instantaneous voltage measure

ment with VOLTS/DIV set at 10M
position. 23

ii

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REV A SEP 1979

LIST OF TABLES

Page

TABLE 1. Battery charge related to operating tem

perature and charging temperature. 5

TABLE 2. Electrical Characteristics 33

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305 DMM Oscilloscope

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305 Operators

GENERAL INFORMATION

INTRODUCTION

The Sony/Tektronix 305 DMM Oscilloscope is a versatile
solid-state (except crt> portable instrument that combines
small size and light weight with the ability to make preci
sion waveform and digital measurements associated with
industrial, military, computer maintenance, and business
machine applications. The 305 is mechanically constructed
to withstand shock, vibration and other environmental
extremes associated with portability. Operating power for
the instrument is provided by external dc, rechargeable
batteries, or normal power-line voltage. Internal circuitry
recharges the batteries whenever the instrument is connect

ed to power-line voltage. Selection of the DMM or oscil

loscope function (or both} is made with front panel push
buttons.

The DMM is autoranging and measures resistance, ac
voltage and dc voltage. Full scale measurements are 2 meg
ohms, 700 Vac and 1000 Vdc. The front panel digital read
out is a 3

-Vi digit display containing an automatic negative
polarity indicator and decimal point locator. No polarity
indication is shown for positive measurements. Input con
nectors for the multimeter are located on the right side of
the instrument cabinet.

Oscilloscope functions provide dual-channel, dc to 5
megahertz vertical deflection with calibrated deflection
factors of 5 millivolts/division to 10 volts/division in a 1-2-
5 sequence. The horizontal deflection system provides cali
brated sweep rates from 0.5 second to 1 microsecond per

division. A X10 magnifier increases the indicated sweep rate

by a factor of ten, extending the fastest sweep rate of 0.1

microsecond/division. The trigger input may be internal or
external, with triggering effective over the full bandwidth
of the vertical deflection system. Calibrated X-Y measure
ments are made with Channel 2 (Y) providing the vertical
deflection and Channel 1 (X) horizontal deflection. Oscil
loscope signal input connectors are located on the left side
of the instrument cabinet The crt display is an 8 X 10 di

vision graticule with each division measuring 0.632 centi

meters (approximately 0.25 inches).

SAFETY INFORMATION

This operating manual contains information which the
user must follow to ensure safe operation of the instru
ment. Warning information is intended to protect the
operator while Caution information protects the
instrument.

REV A SEP 1979 305 Operators 1

WARNING

High voltage is present inside this instrument. To
avoid electric-shock hazard, operating personnel
must not remove the protective instrument
cover. Component replacement and internal ad

justments must be made by qualified personnel

only.

In the ac power source mode, the 305 DMM Oscillo
scope operates from a single phase power source, which
has one of its current carrying conductors at ground (earth)
potential. Operation from other power sources where both
current carrying conductors are live with respect to ground
(such as phase-to-phase on a multi-phase three wire system I
is not recommended because only the line conductor has
over-current (fuse) protection w ithin the instrument.

This instrument has a 3-wire power cord with a 3-
contact plug for connection to the power source and to
protective ground. The plug protective-ground contact con
nects (through the cord protective grounding conductor) to
the accessible metal parts of the instrument. For electric-
shock protection, insert this plug into a socket outlet that
has a securely grounded protective-ground contact.

L)o not defeat the grounding connection. Any interrup
tion of the grounding connection can create an electric-
shock hazard. Before making external connections to this
instrument, always ground the instrument first by connect
ing the power cord to a proper mating power outlet, that
is known to be properly grounded.

OPERATING VOLTAGE

This instrument may operate from an external dc source,

rechargeable batteries (supplied with the instrument), or a

115 or 230 volt ac nominal line voltage.

External DC Power Source Operation

The 305 can operate from an external dc power source
of +9 to +32 volts. Set the Power Source Selector switch to
the EXT DC position (Figure 1). Apply external dc voltage
to the two banana jack inputs using the cable assembly
supplied with the instrument.

Internal Battery Power Source Operation

To operate the instrument from the internal battery
source, set the Power Source Selector switch to the BAT
TERY position (Figure 1). Battery voltage is indicated on
the DMM digital readout when all DMM FUNCTION push
buttons are in the out position.

2

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REV A SEP 1979

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AC L IN t V U L I A lib H A N lit IN UIC A I U K

a ) INDICATES NOMINAL AC INPUT VOLTAGE (116 OR

> < 230 V) FROM WHICH INSTRUMENT MAY BE

B ) OPERATED.

©

POWER SOURCE SELECT SWITCH
OPERATES 305 FROM AC OR EXT DC POWER

SOURCE WITH FULL CHG APPLIED TO INTERNAL
BATTERIES.

©

OPERATES FROM AC OR EXT DC POWER SOURCE
WITH TRICKLE CHG APPLIED TO BATTERIES.

©

OPERATES 305 FROM INTERNAL BATTERY POWER
SOURCE
AC POWER SOURCE OPERATION

©

CHECK THAT THE AC LINE VOLTAGE RANGE
INDICATOR DISPLAYS THE NOMINAL AC LINE

VOLTAGE AVAILABLE I115 OR 230 V AC).

®

SET THE POWER SOURCE SELECT SWITCH TO AC,
FULL OR TRICKLE CHG.

WARNING I

©

WHEN OPERATING FROM EXTERNAL DC OR

INTERNAL BATTERIES THE INSTRUMENT GROUND
CONNECTOR MUST BE CONNECTED TO A
PROTECTIVE EARTH GROUND.

©

©

SET THE POWER SOURCE SELECT SWITCH TO ONE
OF THE EXT DC POSITIONS.

APPLY EXTERNAL DC POWER SOURCE h9 TO

♦ 32 V DC) TO THE BANANA JACK INPUT.

©

BATTERY POWER SOURCE OPERATION
SET THE POWER SOURCE SELECT SWITCH TO

BATTERY POSITION. _________

IWUtiMM

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(2423 0712424 26

Figure 1. Description o f power source operation.

REV A SEP 1979

305 Operators

3

WARNING I

Change o f ac voltage must be accomplished by
qualified service personnel.

AC Power Source Operation

The AC Input Voltage Selector switch permits the 305
to be operated from a 115 or 230 volt ac nominal line volt
age source, at 48 to 440 hertz I Figure 1) The Power Source
Selector switch must be set to the proper AC position. The
ac line voltage fuse must be changed when selecting a dif
ferent nominal line voltage. Any fuse change requires re
moval of the instrument cabinet and must be accomplished
by qualified service personnel.

INTERNAL BATTERY OPERATION

WARNING I

Change or replacement of batteries must be accom
plished by qualified service personnel

I ne jud teatures oattery operation irom six recuarye-
able nickel-cadmium cells (1.2 volts each, total nominal
voltage of 7.2 Vdc). The operating time of the internal
batteries depends upon display intensity, state of battery
charge, discharge temperatures, and the instrument function
being used; oscilloscope, DMM, or both. When the instru
ment is operated at +20°C to +303C (+C8 F to +86°F),
the typical operating time of fully charged batteries with
both oscilloscope and DMM in operation is approximately

1.6 hours.

A light-emitting diode (LED), labeled 'ON (FLASHES
WHEN LOW)', is steadily illuminated to indicate that the
instrument oscilloscope function is on, and the battery
charge is sufficient for operation. When battery charge is
low, the LED flashes on and off indicating that batteries
require recharge or possible replacement. An automatic
battery over-discharge protection circuit will turn the instru
ment off to prevent excessive discharge, which could result
in permanent battery damage.

During DMM operation, the digital readout alternates
between a normal display a nd---------------if the power
source voltage drops too low for proper DMM operation.

4

305 Operators

REV A SEP 1979

BATTERY CHARGING

TABLE 1

To apply full charge to the batteries, connect the instru
ment to a power line, turn SCOPE POWER and DMM
POWER off, switch the Power Source Selector switch to
AC FULL CHG position, and allow at least 16 hours for the
batteries to become fully charged. To obtain the longest
Operating life for the batteries, the instrument should be
turned on at least once a month and the batteries dis
charged to where the oscilloscope SCOPE POWER LED
flashes, and then recharged for 24 hours. This procedure

balances the charge on the batteries and reduces the

possibility of any cell becoming reverse charged The

instrument may be operated while batteries are being

charged.

The energy capacity of nickel-cadmium cells varies with

the temperature at which they are charged and operated.

Table 1 shows the percentage of full charge capacity at
various charging and operating temperatures.

Battery charge related to

operating temperature and charging temperature.

Charging Operating Temperature

Temperature -1 5° C +20° to +25" C

♦55s C

0°C

40%

60%

50%

♦20° to +25° C

65%

100%

85%

*40° C 40%

65%

55%

BATTERY CARE

Nickel cadmium cells will self-discharge when the instru
ment is not used often or stored for extended periods of
time. The rate of self-discharge is dependent upon tempera
ture and humidity. When the instrument is to bo stored for
extended periods of time, particularly at high temperature
or humidity, the batteries should be charged for at least

16 hours every two weeks, or leave the 305 connected to a
power line with the Power Selector switch set to AC
TRICKLE CHG position.

<®

305 Operators

5

CONTROLS AND CONNECTORS

Controls and connectors necessary for proper operation
of the instrument are located on the front, side, and rear
cabinet panels. To make full use of the capabilities of this
instrument, the operator should be familiar with the func
tion and use of each external control and connector. A
brief description and use of each external control and con
nector is given herein

POWER SOURCE AND CONNECTORS

WARNING |

Change o f ac input voltage must be accom
plished by qualified service personnel only.

1. Power Source Selector switch-Three position switch
provides operator selection of ac line voltage, external dc
voltage or battery operation. The ac position, in conjunc
tion with the AC Input Voltage Selector switch, allows the
305 to be operated over a range of ac line voltages. Power
Source Selector switch also provides operator selection of
a Full or Trickle charge rate to internal batteries (Figure 21.

2. AC Input Voltage Selector switch-In conjuction
with the Power Source Selector switch, allows the instru
ment to be operated from 115 or 230 nominal ac line
voltage (Figure 2).

Figure 2. View of rear cover.

6 305 Operators

REV A SEP 1979

3. + and - Inputs for applying external dc power

source {+9 to +32 volts! {Figure 3).

4. DMM INPUT-Connector to apply external voltages

or resistance to be measured to the digital multimeter

(Figure 3).

5. Ground Connector-Connector for common ground
connection from the power source or associated instruments
or devices under test {Figure 3).

6. CHI (X) INPUT-BNC connector to apply an external
signal to the input of the CHI vertical system, or X-axis
deflection {horizontal) in the X-Y mode of operation
(Figure 4). The maximum safe ac or dc voltage coupled to

the CHI (CH2 or EXT TRIG INPUT, if applicable) input
connector should not exceed 250 V (dc + peak ac).

7. CH2 (Y) INPUT-BNCconnector to apply an external
signal to the CH2 vertical system, or Y-axis (vertical) in the
X-Y operation mode (Figure 4).

8. EXT TRIG INPUT-BNC connector to apply an ex
ternal trigger input signal (Figure 4).

9. Ac Line Cord-Connects the instrument to an ac

power source (Figure 3). The cord may be conveniently

stored by wrapping it around the feet on the rear cover

(Figure 4),

Figure 3. Right tide view of instrument cabinet. Figure 4. Left side view of instrument cabinet.

REV A SEP 1979

305 Operators

7