Tektronix 5A26 User manual

Table of contents

Other Tektronix Amplifier manuals

Tektronix

Tektronix 7A16P User manual

Tektronix

Tektronix 7K11 User manual

Tektronix

Tektronix 7A26 User manual

Tektronix

Tektronix 7B53A User manual

Tektronix

Tektronix 7A19 User manual

Tektronix

Tektronix Z User manual

Tektronix

Tektronix 7a15 User manual

Tektronix

Tektronix 11A72 Owner's manual

Tektronix

Tektronix 7A16 User manual

Tektronix

Tektronix 7a15a User manual

Tektronix

Tektronix 7A12 User manual

Tektronix

Tektronix P6046 User manual

Tektronix

Tektronix TCPA300 SERIES User manual

Tektronix

Tektronix 7A22 User manual

Tektronix

Tektronix 11A32 Assembly instructions

Tektronix

Tektronix 7A14 User manual

Tektronix

Tektronix 3240 User manual

Tektronix

Tektronix 7a15 User manual

Tektronix

Tektronix 7A26 User manual

Tektronix

Tektronix 7K11 User manual

Tektronix

Tektronix 7A29 User manual

Tektronix

Tektronix 7A18 User manual

Tektronix

Tektronix 2A60 Product guide

Tektronix

Tektronix AM 502 User manual

Popular Amplifier manuals by other brands

ASTRO

ASTRO HVO V40 P operating manual

Marantz

Marantz SUPERSCOPE BLA-545 Service data

NAD

NAD CI980 Quick setup guide

Technics

Technics SE-CH770 Service manual

Harman Kardon

Harman Kardon HK6300 instruction manual

NAD

NAD T975 owner's manual

McIntosh

McIntosh MA6850 Brochure & specs

Electro-Harmonix

Electro-Harmonix ENGLISH MUFF’N manual

Viatron

Viatron Autrix Technical manual

GME

GME GA9800 instruction manual

Atlas

Atlas CP700 Specification sheet

Roland

Roland KC-1000 owner's manual

Pyle

Pyle PFMRA350BW user manual

Advantage

Advantage S-250 manual

IRT Electronics

IRT Electronics DVA-3007 manual

Dimavery

Dimavery BA-100 Series user manual

Sony

Sony XM-S400D operating instructions

Schertler

Schertler ROY X quick guide

ι

ι

ι

ι

ι

ι

ι

ι

ιι

ι

Ι

T

EK

T

R

O

N

IX

1

1

1

1

1

Te

k

tronix,

Inc

.

Ρ

.

Ο

.

Box500

Beaverton,

O

r

egon

97077

ι

ο7

α

-

ιο

47-

οο

I

N

ST

R

UCTIO

N

M

A

NU

A

L

Serial

Number

F

irst

P

ri

n ting

JUNE

1975

WARRANTY

All

TEKTRONIX

instruments

are

w

arrantedagainst

detectivematerials

and

wor

km

an

shi

p

for

one

y

ear

.

A

ny

q

u

estions

w

ith

r

espect

to'

the

w

arra

n

t

y

s

h

o

u

ld

betaken

up

with

your

TEKTRONIX

Field

En

gi

neer

-

or

representative

.

All re

qu

ests

for

repairs

and

replacement

parts

sh

o

u

ld

b

e

directed

to

the

TEKTRONIX

F

iel

d

Office

or

representative

in

your

area

.

This

ωίΗassu

re

you

t

h

e

fastest

possible

service

.

P

lease

include

instrument

Type

N

u

mber

o

r

P

art

Number

and

Ser

Number

w

ith all

re

qu

ests fo

r

parts

or

ser

u

ί

r

e

.

Specifications

and

price

change

privileges

reserved

.

Co

p

yrig

h

t ,

1975

by

Te

k

tro

n

ix,

Inc

.,

B

eaverto

n

,

Oregon

.

P

rinte

d

i

n

t

he

U

n

ited

States

of

A

m

erica

.

All

rig

h

ts

reserved

.

Contents

of

t

h

is

p

ublicatio

n

m

ay

not

be

re

p

roduce

d

i

n

any

fo

r

m

w

it

hou

t

p

er

m

ission

of

Te

k

troni

x

,

Inc

.

U

.S

.A

.

and

foreig

n

T

E

KTR

ON

IX

products

co

vered

by

U

.S

.

a

nd

foreig

n

paten

ts

and/or

pate

n

ts

pe

ndi

n

g

.

T

EK

TR

ON

IX

is

α

registere

d

trademar

k

of

Tektronix,

Inc

.

ι

10

ι

ι

TA

BLE O

F

CO

N

T

ENTS

P

AG

Ε



P

AG

Ε

LIST

O

F

ILLUSTRATIONS



i



S

E

CTIO

N

2

T

HE

O

R

YO

F

O

PER

ATIO

N

L

IST

O

F

TA

BLE

S



i



BL

OC

K

DIAG

R

A

M

DE

SC

R

I

P

TIO

N

2-1

S

E

CTIO

N

1

O

PER

ATI

NG

I

N

ST

RU

CTIO

N

S



CI

R

CU

IT

O

PER

ATIO

N

2-2

PREP

A

R

ATIO

N

F

O

RU

SE



1-1



PRE

A

MPL

I

F

I

ER



2-2

CO

N

T

R

O

L

S,

CO

NNECTO

R

S,

A

ND



1-1



OU

T

PU

T

A

MPL

I

F

I

ER

S



2-3

I

N

DICATO

RS



RE

ADO

U

T



2-5

B

ASIC

O

PER

ATIO

N

1-3

P

re

p

aration



1-3



S

E

CTIO

N

3

REPL

AC

E

A

BLEELE

CT

R

ICA

L P

A

R

TS

Ste

p

Attenuator

B

alance

Ad

j

ustme

n

t



1-3

Gain

C

h

ec

k

1-4



S

E

CTIO

N

4 S

ERV

ICE

I

NF

O

RM

ATIO

N

DE

TAI

LE

D

O

PER

ATI

N

G

I

NF

O

RM

ATIO

N

1-4



S

ERV

IC

ES

A

V

AI

L

A

BLE



4-1

Applying

Signals



1-4



M

AI

N

T

EN

A

NC

E

4-1

P

re-C

h

arging



1-4



Circ

u

it

B

oar

d

R

emoval



4-1

Sig

n

al

In

p

ut

Connectors



1-4



AD

JU

ST

MEN

TS

A

F

T

ER

REP

AI

R



4-1

H

ig

h Im ped

ance

In

p

u

t



1-5



DIAG

R

AM

S



4-2

Dis

p

lay

P

olarity



1-5



BL

OC

K

DIAG

R

A

M

Deflection

F

actor



1-5



AD

JUST

MEN

T

PR

OC

E

D

URE

V

oltage

Comparison

M

eas

urements



1-5



P

A

R

T

L

OCATIO

NS

A

N

D

DIAG

R

AM

S

Diffe

r

en

tial

O

p

eration



1-5

V

oltage

Pr

obes



1-6



S

E

CTIO

N

5

REPL

AC

E

A

BLE

ME

CH

AN

ICA

LP

AR

TS

Differential

M

easurements



1-6

S

PE

CI

F

ICATIO

N

S



1-7



C

H

A

N

G

E

I

NF

O

RM

ATIO

N

LIST

OF

ILLUSTRATIONS

FIG

URE



FIG

URE

NO

.



P

AG

E

NO

.

1-1



5

Α

26 Du

al

Differential

Am

p

lifier

.



ii



4-3



A

dju

stment

locations

.

1-2



Front-panel

cont

r

ols,

conn

ectors

an

d

1-2



4-4



Α

1,

A2-Channel

1

and 2

Pr

eam

p

lifier

circuit

i

nd

icators

.



b

oar

d

component

an

d

test

p

oint

locations

.

1-3



Dimensions

.



1-9



4-5



Α

2,

A2-Channel

1 a

nd2P

reamplifier

circuit

2-1



F

loating

P

ower

Su pp

ly

d

etaile

d

bloc

k

2-4



boar

d

locatio

n

s .

d

iagram

s

h

owing

sta

n

d

i

ng

cu

r

re

n

t

p

at

h

s



4-6



A3-Main

circuit

boa

r

d

com

po

n

e

n t a

n

d

test

t

hrough

t

he P

ream

p

lifie

r

.



p

oint

locatio

n

s

.

T

he

ill

u

strations

in

Section

4

are

locate

don

fol

dout

pages



4-7



A3-Main

ci

r c

u

it

b

oar

d

locatio

n

.

at

th

e

back

of

the

ma

n

ual

.



4-8



A3-Main

circ

u

it

b

oar

d

component

locations

.

4



4-9



A3-Main

circuit

board

location

.

-1



Circ

u

it

b

oar

d

locations

.

4-2



Common-mode

re

j

ectio

n

(cm

r )

display

.

L

IST

O

F

TA

BLES

TA

BLE

NO

.



P

AG

Ε

1-1



E

lectrical

Sp

ecifications



1-7

1-2



E

nvironmental

S

p

ecifications



1-8

1-3



Ph

ysical

Specifications



1-8

5

Α

26

Fig

.

1-1

.

5

Α

26

Dual

Differential

Amplifier

.

ι

ι

ι

ι

T

he

5

Α

26

Dual

Differe

n

tial

Am

p

lifier

is

α

d

ual-trace

h

ig

h

-gain

d

ifferential

amplifier

plug-in

for

u

se

wit

hTe

k

tronix

5000

Series

Oscilloscopes

.

T

h

e

unit

contains

two

i

d

entical

in

d

e

p

en

dent

am

p

lifier

chann

els

t

h

at

feature

h

ig

h

sensitivity

an

dα

h

ig

h

common-

mo

d

e re

j

ectio

n

ratio

.

E

achch

a

n

nel

h

as

α

ban

dwid

t

h

capability

of

do

to

1

mega

h

ertz,

an

dα

front-

p

anel

pu

s

h button switch

allows

the

re

d uction of

t

he

up

p

er

b

an

d

widt

h

limit,

t

hu

s

increasing

t

h

e

signal-to-

n

oise

ratio

for

low

freq

u

ency

applications

.

E

it

h

er

chann

el

may

be

used

for

single

c

h

annel

d

isplays,

or

electronically

switche

d

to p

ro

d uce

dual-trace

dis

p

lays

.

An

ill

u

minate

d k

no

bsk

irt

provi

d

es

α

d

eflectio

nfactor

rea

dout,

w

h

ic h

is

also

d

isplayed

on

t

h

e

crt

w

h

en used

i

nan

oscillosco

p

e

with

rea

dou

t

cap

abilities

.

PREP

A

R

ATIO

N

F

OR

US

E



4



V

O

L

TS/DI

V

Switc

h

es-

V

olts

per

ma

j

or

graticule

Ο

d

ivisio

n

.

Selects

calibrate

dd

eflection

factors

from

'



T

he

5

Α

26

is

cali

b

rate

d

an

d

ready

for

use

w

h

en

receive

d

.



50

microvolts/

d

ivision

to

5

volts/division

;

16

steps

in

T

he unit

may

be

installed

in

any

p

l

u

g-in

com

p

artment

.

R

e-



α

1-2-5

se

q

uence

.

Kn

ob

s

k

irt is

illuminate

dto

in

d

i-

fer

to

t

he oscilloscope

instruction

man

u

al

for

information



cate d

eflection

factor,

and

10

Χ

scaling

of

bot

h k

no

b

on

Χ

-

Υ

operation

.

To

install,

align

t

he u

pp

er

an

d

lower



s

k

irt

and

crt rea

d

out

is

provi

de

d

automatically

w

h

en

grooves

of

t

h

e

5

Α

26

with

t

he

plug-in

compartment

track

s,



α

10

Χ

co

d

e

dp

robe

is

used

.

an

d

fully

i

n

sert

t

he 5

Α

26

u

n

til

it

loc

k

s

i

nto place

.

To

re-

move,

pull

the

release

latc

hto

disengage

t

h

e

5

Α

26

from

t

he

'

~

oscillosco

p

e

.

CA

L

(

V

aria

b

le

V

O

L

TS/DI

V

)

Controls-

P

rovi

d

es

υη

-

calibrated

continuously

varia

b

le

d

eflection

factors

between

t

he

cali

b

rate

d

settings

of

t

he

VO

L

TS/DI

V

CO

N

T

R

O

L

S,

CO

NNE

CTO

R

S,

A

N

D

I

N

DICATO

R

S



switc

h

and

exten

d

st

h

e

d

eflection-factor

range

to

12

.5

volts/

d

ivision

.

T

he

following

descri

b

es

t

h

e

f

u

nction

of

t

h

e

front-

p

anel

controls,

con

n

ectors,

an

d

indicators

.

R

efer

to

F

ig

.

1-2

for

t

he

locatio

nof

t

h

e

co

n

trols,

con

necto

r

s

and

in

d

icators

.

M

ore

information

is

given

u

nder

Detaile

d

O

p

erating

Information

.

DIS

PL

AY

P

ush

B

utton-Applies

and

removes

logic

levels

to

t

he oscilloscope

system

to

enable

or d

isa

b

le

p

lug-in

operation

.

Switc

h

is

functional

on

ly

w

hen

p

l

u

g-in

is

op

erate

d

in

one

of

t

he

vertical

d

eflectio

n

p

l

u

g-in

compartments

.

Ο

2



P

OS

Co

n

trols-

P

ositions

d

is

p

lay

vertically

.

ι

BW

L

I

M

IT Pu

s

h

B

uttons-Allows

re

du

ction of

t

he

upper b

andwi

d

t

h

limit

to

increase

t

h

e

signal-to-noise

ratio

for

low-frequency

applications

.

Selects

upp

er

ban

dwi

d

t

h

limit

at

eit

h

er

1

mega

h

ertz

(

bu

tton

o

u

t)

or

10

k

ilo

h

ertz

(

bu

tton

in)

.

O

PER

ATI

N

G

I

N

ST

RU

CTIO

N

S

Section

1-5

Α

26

ST

EP

ΑΤΤΕΝ

B

A

L

Ad

j

ustments-

B

ala

n

ces

t

h

e

in

p

ut

am

p

lifier

for

minimum

trace

s

h

ift

t

hrou

g

h

o

u

t t

h

e

d

eflection

factor

gain-switc

h

ing

ra

n

ge

.

Input

Coup

li

n

g

P

ush B

uttons

AC-O

U

T:DC

.

B

utton

pus

h

e

d

in

selects

cap

acitive

coupling

of

signal

app

lie

d

to

associate

d+

or

-

inp

ut

connecto

r

;

button out

selects

d

irect

couplin

g

of inpu

t

sig

n

al

.

GND

.

Grou

n

d

s t

he preamplifier

in

put

an

d

connects

input

signal

to

groun

d

t

hroughα

1

mego

h

m

resistor

.

PRE

CH

G

.

B

ot

h

AC

and

GN

D

buttons

pus

hed

in

p

ermits

p

rec

h

arging of

t

h

e

cou

p

ling

cap

acitor

to

t

h

e

input

sig

n

al

d

o

level

.

R

elease

GN

D

button

fo

r

measurement

.

M

OD

EP

ush

B

utton

s-Select

c

h

annel to

b

e d

is

played

an

d

illumi

n

ate

t

h

e

p

ro

p

er

d

eflection

factor

setting

(1

Χ

or

10

Χ

)

on

t

he

VO

L

TS/DI

V

switc

h k

no

bsk

irt

.

B

oth buttons

pus

hed

i

n

provides

α

du

al-trace

d

isplay

.

Operating

Instructions-5A26

r

ο

Fig

.

1-

2

.

Front-panel

controls,

connectors,

and

indicators

.

Operating

Instructions-5A26

ι

ι

AC



O

UT

:

DC

(b

utton out)

+

an

d

-

In

p

u

t

Connectors-

BN

C

connectors

for

app

li-

cation of

external

voltage

signals

.

Connector

labele

d



GND



GND

(

bu

tton

in)

+

indicates

t

h

at

α

p

ositive-going

signal

will

cause

upwar

d

d

eflectio

n

;

connector

la

b

ele

d

-

indicates

t

h

at



M

OD

E



CH

1

an

d

CH

2

α

positive-going

sig

n

al

will

cause

downwar

d d

eflectio

n

.



(

b

uttons

in)

Con

nectors

inclu

de

co

d

e

d

-

prob

e

input

rings

for

activating

t

h

e

rea

dou

t

w

hen

using

readout-co

d

e

d

p

robes

.



d

.

A

d

j

ust

intensity

control for

normal

viewing

.

Traces

sh

oul

d

a

pp

ear

near

gratic

u

le

center

.

B

ASIC

O

PER

ATIO

N

e

.

Set

t

he

VO

L

TS/D

Ι

V

switc

h

es

to

.1

.

If

traces

s

h

ift,

Preparation



a

d

ju

st

t

he

ST

EP

ΑΤΤΕΝ

B

A

L

control

as

d

escri

bed

in

'



T

he

following

procedures

are

i

n

te

nded to

h

el

p p

lace

t

h

e

trace

on

t

hesc

r

ee

n

q

uic

kly

and

prepare

t

he

instrument

for

immediate

use

:

'



α

.

I

n

sert

5

Α

26

all t

he

way

into

oscillosco

p

e

plug-in

com

p

artment

.

ι

T

R

IGG

ER

Push

Bu

tton-Selects

time

base

triggeri

n

g

signal

from

eit

h

er

channel

.

b

.

Turn

oscilloscope Intensity

control to

mi

d

ra n

ge and

t

u

rn

oscilloscope

syste

m

p

ower

on

.

P

reset

time-b

ase

an

d

triggering

controls for 2

millisecon

d

/

d

ivision

sweep

rate

10



and

a

u

tomatic

triggeri

ng

.

c

.

Set 5

Α

26

front-

pan

el

controls

as

follows

:

ι

ι

ι

ι

ι

DIS

PL

AY



ON

(butto

n

in)

T

RIGG

ER



OU

T

:

CH

1

(b

u

tto

n

out)

P

OS



M

i

d

ra

nge

BW

L

I

M

IT



OU

T

: 1

MHz

(b

utton

o

u

t)

V

O

L

TS/D

1

V



5

ST

EP

ΑΤΤΕΝ

B

A

L



M

i

d

ra

nge

C

H

1

an

d CH2

+Input

Cou

p

li

n

g

CH

1

and

C

H

2

-

In

p

ut

Coupling

Step

Attenuator

B

alance

A

dju

stment

proce

dure

.

f

.

M

ove

CH

1

trace

2 d

ivisions

b

elow

graticule

h

orizontal

centerline,

and

C

H

2

trace

to b

ottom

of

graticule

with

P

OS

controls

.

g

.

Apply400

millivolt

pea

k

-to-

p

ea

k

signal

fro

m

oscillo-

scope

cali

b

rator

loop

wit

hα

test

lea

d or

1

Χ

probeto

CH

1

+

in

p

ut

connector

.

h

.

R

elease

CH

1

+

GND

b

utton

.

Disp

lay

will

be

α

s

qu

ar

e

wave

4

d

ivisions

in

amplitude

with

bottom

of d

is

p

lay

at

refere

n

ce esta

b

lis

hed

in

step

(f)

.

i

.

P

osition

b

ottom

of

s

q uare

wave

to

graticule

h

orizontal

centerline

.

j

.

Pu

s

h

in

C

H

1

+

AC

button an

d

note

that

display

s

h

ifts

d

ownwar

d 2

divisio

n

s .

k

.

Disconnect

test

lead

from

CH

1

+

in

put an d connect

to

CH

2

+

in

pu

t

.

Ι.

P

ush

in

T

RIGG

ER

butto

n

for

CH

2

triggering

an

d

repeat

ste

p

s

(f) t

h

ro

ug

h

(j)

for

CH2

operation

.

AC



OU

T

:

DC

(button



Ste

p

Attenuator

B

alance

A

d

j

ustment

Out)



Wh

en

t

h

e

ST

EP

ΑΤΤΕΝ

B

A

L

control

is

not

properly

a

dj

ust-

ed

,

t

h

e

d

is

p

lay

will

s

h

ift

vertically

(

d

ue

to

α

do

imbala

nce

i

n

GND



G

ND

(

button

in)



t

he

am

p

lifier)

as

t

h

e

VO

L

TS/DI

V

switc

h

is

rotate

d

t

h

ro

ugh

-

out

its

range

.

T

he

s

h

ift

is

more

noticeable

on

t

he

most

sensitive

positio

n

s

.

Op

erating

Instructions-5A26

α

.

Set

VO

L

TS/DI

V

switch to 5

.

Ground

both

+

an

d

-



b

.

Wait

about

1

second

for

coupling

ca

p

acitor

to ch

arge

.

inputs

(G

N

D

bu

ttons

pu

s

h

e

d

in)

and p

osition

trace to

graticule

h

orizontal centerline

.

c

.

R

elease

GND

bu

tton

a n

d ac

com

p

onent

can

b

e

meas

u

re

d

in

usual

manner

.

b

.

A

dj

ust

ST

EP

ΑΤΤΕΝ

B

A

L control

for

minim

u

m

trace

s

h

ift

as

VOL

TS/DI

V

switch

is

rotate

d

t

h

rou

g

ho u

t

its

range

.



Signal

In

p

ut

Connectors

Wh

en

connecting

signals

to

t

h

e

+

an

d

-

in

p

ut

connectors

on

t

he

5

Α

26,

consi

d

er

t

h

e

met

h

od

of co

up

ling

that

will

be



,

Gain

C

heck



u

se

d

.

Sometimes

un

s

h

iel

d

e

d

test

leads

can

b

e

u

se

d to

Wh

en

t

h

e

5

Α

26

is

first

inserte

d into

α

p

lug-in

com

p

artment,



connect

t

h

e

5

Α

26

to α

signal

sou

rce,

p

artic

u

larly

w

h

e

n

α

t

h

e

amplifier

gain

may

be

c

heck

e

d

an

d

ad

j

usted

if

necessary

.



h

ig

h

level,

low-frequency

signal

is

monitore

d

at

α

low

i

m

-

See

A

d

ju

stment

Proce

d

ure

in

Section

4

of

t

h

is

manual

for



p

ed

ance

p

oint

.

H

owever,

w

h

en

any

of

t h

ese

factors

are

com

p

lete

i

n

structions

.



missing,

it

becomes

i

n

creasingly

important

to use

s

h

iel

d

ed

signal

cab

les

.

In

all

cases,

t

he

signal-trans

p

orting

lea

d

s

s h

ou

l

d

be

k

e

p

t

as

s

hort

as

practical

.

D

E

TAI

LE

DO

PER

ATING

I

NFO

RM

ATIO

N

Applying

Signals



Wh

en

ma

k

ing

si

n

gle-e

nded

i

nput

measurements

(conve

n

tio

n

al

amplifier operation), b

e

sure

to establis

h

α

common

groun

d

con

nection

between

th e

d

evice

un

d

er test

an

d

t

he

5

Α

26

.

T

h e

s

h

iel

dofα

coaxial

cable

is

normally

u

se

d

for

t h

is

pur

pose

.

ι

ι

If

t

h

e

maxim

u

m

input

voltage

rating

at

t

he gates

of

t

h

e

input

FE

T's

is

exceeded,

t

he

gates

a

r

e



In

some

cases,

d

ifferential

meas

u

rements

re

q

uire

no

common

clampe

d

at

about

+

or

-

10

volts

.

If

t

h

e

signal



ground

connection,

a

nd

t

h

erefore

are

less s

u

sce

p

tible

to

sou

r

ce

can

supply

m

ore

t

ha

n

1/16

ampere,

t

he



interference

by

ground-loop

currents

.

Some

pro

b

lems

wit

h

input

protective

fuse(s)

will

o

p

e

n

.



stray

magnetic

co

u

pling

into

t

h

e

signal

transporting

leads

can

also

be

minimize

d

by

u

sing

α

d

ifferential

rat

h

er

t

h

an

α

single-en

d

e

d

measurement

.

T

h

ese

consi

d

eratio

n

s

are

d

is

Wh

en meas

u

ring

unk

now

n

voltages,

use

t

he h

ig

h

est

deflection



cu

sse

d

later

in this

sectio

n

under

Differential

O

p

eration

.

factor

first

.

If

t

he deflection

is

too

small

to

ma

ke

t

he

meas

u

rement,

switch to

α

lower

deflectio

n

factor

.

It is

always

im

portant to

consi

der

t h e

signal so

urce

loa

d

ing

(an

d

res

u

lting

ch

ange

in t

he

source

operating

c

h

aracteristics)



'

P

re-C

h

arging



d

u

e to

t

he

signal-trans

p

orting

lea

d

s

an

d

t

he inpu

t

circ

u

it

of

Wh

en

only

t

he ac

com

p

onent

of

α

signal

having

bot

hac and



t

h e

5

Α

26

.

T

h

e

circuit

at

t

he

in

pu

t

connectors

can

normally

d

o

components

is

to

b

e

measured,

t

he

p

re-c

h

arge

circ

u

it



b

e

re

p

rese

n

te

d

by

α

1

mego

h

m

resistance

to

ground

p

arallel-

permits

ch

arging

t

he

co

u

p

ling

ca

p

acitor

to

t

h

e

inpu

t

signal



ed

by

about

47

p

icofarads

.

Α

few

feet

of

s

h

iel

ded

ca

b

le



,

d

o

level

.



(20

to

40

p

icofara

d

s

p

er

foot)

may

increase

t

h

e

p

arallel

capacitance

to

100

picofarads

or

more

. I

n

ma

ny

cases,

t

he

effects

of

th

ese

resistive

and cap

acitive

loa

d

s

may

be

too

great

and

it

may

be

desira

b

le

to

minimize

t

h

em

t

h

roug

h

t

h

e



,

CAUTION



use

of

an

attenuator

pro

be

.

If

t

h

e

5

Α

26

input

is

connected

to

α

large

d

o

voltage

sour

ce

(10

volts

pea

k or

mo

r

e),

use

t

he

p

rech

arge

provision

.

Damage

to

t

h

e

signal



Attenuator

probes

not

only

decrease

t

he

resistive-ca

p

acitive

so

u

rce

could

r

esult since

t

he

pea

k

current



loa

d

ing

of

α

signal

source,

but

also

exten

d

t

he

measureme

n

t

t

hro

u

gh

t

h

e

ac

coupling

capacitor

and

t

he



range of

t

h

e

5

Α

26

to

inclu

d

e

substantially

h

ig

h

er

voltages

.

input

protection

circuitry

is

limited

only

by



Passive

atten

u

ator

p

rob

es

h

avi

n

g

attenuation

factors of

10

Χ

,



,

t

he

signal

source

internal

resistance

.



100

Χ

,

and

1000Χ

,

as

well

as

oth

er

s

p

ecial-

pu

r

pose

types,

are

available

t

h

roug

h

your

Te

ktronix

F

ield

E

ngineer

or

F

iel

d Office

.

α

.

B

efore

co

n

necting 5

Α

26

to

α

signal

contai

n

ing

α

d

o

com

p

one

n

t,

p

us

h

in

AC

and

G

N

D

b

uttons

.

T

h

en

connect



Some

measureme

n

t

situations

re

q

uire

an

extremely

h

ig

h

inpu

t

to

circ

u

it

u

nd

er test

.



resistance

in

pu

t

to

t

he 5

Α

26

with very

little

sou

rce

loadi

n

g

ι

ι

1

1

ι

or

signal

attenuation

.

In

s

uc

h

situatio

n

s,

α

passive

attenuator



Deflection

F

actor

p

robe

cannot

b

e

used

.

H

owever,

t

h

is

proble

m

may

be

solved



The

amount

of trace d

eflection

produced by

α

signal

is

'



by

using α

FE

T

Pr

obe

or

t

heh

ig

h-imp

e

d

ance

i

np

ut

p

rovision



determi

n

e

d

by

the

signal

am

p

litu

d

e, t

h

e

atten

uation

(if

any)

of

t

h

e

5

Α

26

as

described un

d

er

H

ig h

-Impe

d

ance

In

pu

t

.



of

t

h

e

pro

b

e,

th

e

setting

of

t

h

e

V

O

L

TS/DI

V

switch

,

an

d

t

he

setting

of

t

h

e

V

aria

b

le

control

.

T

h

e

d

eflection

factor

settings

are

calibrate

d

only

w

h

en

t

he

V

ariable

control

is

H

ig

h-Im

p

edance

In

put



rotate

d

f

u

lly

clockwise

i

n

to

t

he deten

t

p

osition

.

In

t

h

e

50

m

t

hro

u

gh

50

μ

p

ositions

of

t

he

V

O

L

TS/DI

V

switch

,

w

here

thein

p

ut

attenuator

is

not

used,

t

he

internal

gate

return

resistors

alone

esta

b

lis

h

t

he

1

mego

h

m

input



T

he

range

of

t

he

V

aria

b

le

control

is

at

least

2

.5

:1

.

It

provides

resistance

.

T

he

removal

of

t

he strap

from

t

he

P

ream

p

lifier



uncalibrated

d

eflection

factors

covering

t

h

e full

ra

nge

circuit

board

(see

F

ig

.

4-4,

C

hannel

1

and

2

P

reamplifier



between

t

he

calibrate

d

settings

of

t

h

e

VO

L

TS/DI

V

switch

.

circuit

board

com

p

onent

an

d

test

point

locations

in

t

he



T

he

V

ariable

control

can

be

set

to

exten

d

t

he

d

eflection

Diagramsan

d P

arts

L

ists

sectio

n

)

d

isconnects

t

hese

resis-



factor to

at

least

12

.5

volts/

d

ivision

.

tors

fro

m

groun

d

an

d

permits

t

he

in

pu

t

FE

T

gates

to

float,

p

rovi

d

i

n

gαvery

h

ig

hinput

impe

d

ance

.

To

re

d

uce

noise

and

obtain

α

more

u

sa

b

le

d

is

p

lay

w

he

n

t

he

V

O

L

TS/DI

V

switc

h

is

set

to

t

h

e

more

se

n

sitive

p

ositions,

T

h

e

in

pu

t

signal

m

u

st

be

k

ept

to

r

elatively

low

amplit

u

des,



p

u

s

h

in

t

he

BW

L

I

M

IT

button

to

re

d

uce

t

h

e

b

a

n

d

wid

t

hto

since

t

h

e

d

eflection

factor

is

restricte

d to

50

millivolts/



10

kH

z

if

t

h

is

limit

does

not

a

ppreciably d

istort

t

hed

esire

d

d

ivision

t

hr

oug

h

50

microvolts/

d

ivision,

an

d

d

o

cou

p

li

n

g



features

of

t

h

e

signal

u

nde

r

ob

servation

.

must

b

e

u

se

dto p

rovi

d

eα

d

o

p

at

h

for

t

he

FE

T

gate cu

rre

n

t

.

V

oltage

Com

p

arison

M

easurements

O

p

erating

Instructions-5A26

NOTE



Some

a

pp

lications

re

q

uire

d

eflection

factors

oth

er

t

han

the

In

t

h

e

0

.1 volt to

5

volt

r

ange

of

t

he

V

O

L

TS/



fixe

d

values provided by

t

he

V

O

L

TS/DI

V

switch

.

One

suc

h

DIV

switc

h

,

t

he

input

impedance

is

pa

r

alleled



app

lication

is

comparison

of

signal

am

p

litu

d

es

by

ratio

by

t

he

resistors

in

t

he

attenuato

r

.

W

h

en

t

h

e



rat

h

er

th

a

n

by

absolute

voltage

.

To

accom

p

lis

h

t

h

is,

a

pp

ly

"



strap

is

removed,

t

he atten

u

ation

ratio

is



αreference

signal to

eit

h

er

+or

-

inputs of

the

5A26,

and

affected,

causing

t

he

deflectio

nfacto

r

s

in

t

h

is



set

the

VO

L

TS/DI

V

switchand

V

aria

b

le

con

trol so

t

h

at

range

to

be

incorrect

.



To

determine

t

h

e

d

e-



t

he

r

eference

dis

p

lay

covers

t

h

e

d

esire

d

number

of

graticule

flect

ί

on

factor,

c

h

ec

k

t

h

e

deflection with

an



d

ivisio

n

s

.

Do

not

ch

ange

t

he

V

ariable

con

trol

settings

input

signal

of

k

nown

amplit

u

de

.



t

h

roug

h

out

t

he

subse

q

uent

comparisons

.

H

owever,

th

e

settings

of

t

h

e

VO

L

TS/DI

V

switchcan be ch

ange

dto

accommodate

large

ratios

.

In

d

oing

so,

regard

t

h

e

nu

m

b

ers

T

h

e

signal

source

impedance

is

an

important

factor,

since



w

h

ic

hdesignate

t

h

e

switc

h p

ositions

as

r

atio

factors

rat

h

er

gate

cu

rrent

will

p

ro

d

uce

an

offset

.

F

or

example,

α

100



t

h

an

voltages

.

p

icoampere

gate cu

rrent

t

hrou

g

h

10

mego

h

ms

produces

α

1

millivolt

offset,

w

h

ic

h

may

result

i

n

sig

n

ificant

error

w

h

ere

small

voltages

are

of

concern

.



Differential

O

p

eration

Single-en

ded

meas

u

rements

often

yield

unsatisfactory

res

u

lts

beca

u

se

of

interfe

r

ence

resulting

from

ground-loop

currents

T

he

h

ig

h

-fre

q

uency

res

p

onse

will

also

d

epen

d

upon

t

h

e



b

etween

the

5

Α

26

and

t

he device

un

d

er test

.

In

oth

er

signal

sou

rce

im

p

eda

n

ce,

si

nce various

s

hu

nt ca

pacitances



cases,

it

may

be

d

esirable

to

elimi

n

ate

α

do voltage

by

means

b

etween

t

h

e

source

and

t

he

input

gate

m

u

st

c

harge

an

d

ot

h

er

t

han

t

he

u

se

of

α

do block

ing

capacitor,

w

h

ic

h

co

u

l

d

d

isc

h

arge

th

roug

h

t

h

at

i

mp

ed

ance

.



limit

t

he

low-frequency

res

p

onse

.

'



Dis

p

lay

P

olarity

T

h

ese

limitations

of

single-en

de

d

measurements

are

effectively

Single-ended

signals

a

pp

lie

d to

t

he

+

in

put

connector

pro-



eliminated

by

connecting

t

h

e

+

inp

ut

and

-

in

p

u

t

to

'



d

uce

α

d

is

p

lay

in

phase with

t

he

in

p

ut signal

.

Signals

a

pp

lie

d

selecte

dp

oints

in

t

h

e

test

circuit

.

Since

t

h

e c

h

assis

of

t

h

e

to

t

he

-

i

npu

t

connector

will

be

inverte

d

.



5

Α

26

nee

d

not

be

connecte

d

in

any

way

to

t

he

test circ

u

it,

t

h

ere are

few

limitations

to

t

h

e

selection

of

t

h

ese

test

points

.

In

any

case,

d

o

not

excee

d

t

he

maxim

u

m

safe

in

pu

t

voltages

.

Α

similar

polarity

relations

h

ip

exists for

d

ifferentially

a

pp

lie

d

.



s

ί

gnals,

but

p

ertai

ns

to

t

h

e

direction of voltage

c

h

ange

at

one

in

put with

res

p

ect

to

th

e

ot

h

e

r

,

rat

h

er

t

han with

res

p

ect



T

h

e

+

an

d

-AC

bu

ttons

sh

ou

l

d bothbe

set

to

t

he

same

to c

h

assis

potential

.



p

ositions,

d

epending

on

t

he

met

hod of

signal

coupling

requ

ire

d

.