Sencore FE16, FE14 Service manual

INSTRUCTION MANUAL FOR THE SENCORE F E 14 & FE 16

FIE L D E F F E C T M E T E R S

The Sencore FE 14 and F E 16 Field Effect M eters						a re a revolutionary new concept
in test	m eters .	They take all the advantages of				a VTVM and combine them with
the advantages of a VOM to make an extrem ely					v ersatile m eter. High input im ­
pedance on all		AC & DC voltage ranges,		peak	to	peak	AC m easu rem ents,		& DC
zero cen ter sca le s combined with zero				warm	up	time,	DC	cu rren t ranges, and
VOM portability m akes the Field Effect				M eter a truly great				instrum ent.	Anyone
in the	e lec trica l or electron ic fields		- serv ice		technicians,			eng in eers, field eng­
in eers,	hams,	exp erim en ters etc. -	will	find that the			Field E ffect M eter		is the

com plete answer to his m easuring needs.

No other m eter in the F E 14 or F E 16 c la s s has all of these features in one instrum ent:

*High input impedance on both AC and DC voltage ranges (10 megohms, and 15 megohm)

*T ru e peak to peak AC ranges.

* Z ero center ranges for solid state servicing.

* DC cu rren t ranges for general testing.

* M irrored scale m eter for greater accu racy in readings.

* M eter protected from overloads.

* C ircuit protected from accidental application of wrong voltages.

*All steel construction for greater durability.

*Battery operated for complete portability.

			FE 14 SPECIFICATIONS
DC VOLTS
Ranges:	0 to 1, 3,		10, 30, 100,	300 and 1000 F U L L	SCALE
	- . 5 to .5 ,		- 1 . 5 to 1 .5 ,	-5 to 5, -1 5 to 15,	-5 0 to	50, -150 to 150
	and -5 0 0 to 500 ZERO CENTER SCA LE RANGES
Input R esistan ce:			15 megohms shunted by 14 PF.
A ccuracy: + 2 1/2%				»
AC R ejection:		30 to 300 tim es (30 to 50db).
AC VOLTS
Ranges:	(Rm s)
	0 to 1,	3,	10, 30, 100,	300 and 1000 F U L L	SCALE
Ranges:	(Peak to Peak)
	0 - 2 . 8 ,	8 . 4 , 28, 84, 280, 840 and 2800 Full			Scale,	frequency
	compensated
Input R esistan ce:			10 megohms shunted by 29 PF.
Frequency Response: F lat: 25HZ to 1MHZ
			3db points:	10Hz to 10MHz
A ccuracy: + 4 1/2%

O H M M ETER

R an ges: 0 to 1000 ohm s, 10K, LOOK, 10 megohms and 1000 megohms A ccuracy: + 2 d eg rees ARC

DC CU RREN T M EASUREM ENTS

Ranges: 0 - 100 m icroam ps, Im a , lOma, lOOma and 1 Ampere A ccuracy: + 3%

Internal Voltage Drop: 200 MV

			F E 1 6 SPECIFICATIONS
DC VOLTS
Ran ges:	0 to 1,	3,	10, 30, 100,	300 and 1000	F U L L	SCA LE
	5 to	. 5,	- 1 . 5 to 1. 5,	- 5 to 5, -15	to 15,	- 5 0 to	50, -150 to 150
	and - 5 0 0 to 500 ZERO CE N TER SCALE RANGES
Input R e s is ta n c e :			15 megohms	shunted by 14 PF at ja c k o r			37 PF thru cable
A ccuracy: + 1 . 5 %
AC R ejectio n : 30 to 300 tim es (30 to 50db),
AC VOLTS
R anges:	(Rm s)
	0 to 1,	3,	10, 30, 100,	300 and 1000	F U L L	SCA LE
R anges:	(Peak to Peak)
	0 - 2 . 8 ,	8 . 4 , 28, 84, 280, 840 and 2800 Fu ll				sca le ,	frequency
	com pensated

Input R esista n c e: 10 megohms shunted by 29 PF at ja c k or 118 PF thru cable Frequency R esponse: F la t: 25HZ to 1MHZ

3db points: 10Hz to 10MHz

A ccuracy: + 3%

OHM METER

Ranges: 0 to 1000 ohm s, 10K, 100K, 10 megohms and 1000 megohms A ccuracy: + 2 degrees ARC

DC CU RREN T MEASUREM EN TS
Ranges: 0 - 100 m icroam ps, Im a, lOma, lOOma and 1 Ampere
A ccuracy: + 3%	full scale
Internal Voltage	Drop: 200MV

G EN ERA L SPECIFICATIONS ON F E 1 4 AND F E 16
M eter: 4 -1 / 2 ", 100 m icroam p + 2%, diode protected and isolated from input
M ultiplier R e s is to r s : 1% p recision type on F E 1 4 ; 1/2% on FE 16
Ohms B attery: 1. 5V "C " cell,			Eveready Type	#1035 o r equivalent
Power supply battery: 9 volt,			Eveready Type	#222 o r equivalent
Weight (le s s	B atteries): 3-1/4		lbs.
D im ensions:	5" w x 7 -3/ 16”h 3 - l/ l6 d
A c c e s s o r ie s :	High Voltage probe (39A19) extends ran ge to 30KV.
CONTROLS ON THE F E 1 4 & F E 1 6
The Field E ffe c tM e te r is		as sim ple to operate		as a standard VOM.	Panel controls
include the RANGE switch,		FUNCTION switch,		m eter ZE R O ADJ,	OHMS AD], and

the off-on switch. The following is a b rief description of each control and how it is used.

O F F -O N switch: The

O FF -O N

switch controls the power to the c irc u it in the Field

E ffect M eter.

In the

O F F position,

the

battery is

disconnected

from the circu it

and the m eter is off.

In the ON position,

the battery voltage is applied to the circu it

and the m eter

is ready to go.

A red flag appears in the switch opening to

indicate

when the Field E ffect M eter is on.

When m easuring current,

the O FF -O N switch

may be left in the O F F position as

no battery power is

needed.

ZERO ADJ:

The ZERO

ADJ is

used

to position the

pointer of

the m eter

over the

z ero

on the extrem e left of the meter

scale

or to position the pointer on the center

zero

when using the zero cen ter ranges of the Field E ffect M eter.

OHMS ADJ:

The OHMS ADJ is the

same as

that

found on m ost

m e te rs .

Prior to

m easuring

resistan ce,

the test leads are shorted

together and

the OHMS ADJ is

rotated for a

full scale

deflection (zero

ohms)

as

read on the ohms scale of the

m eter.

FUNCTION SWITCH:

The FUNCTION switch s e le c ts the type of m easurem ent to be

preform ed.

Minus or Plus DC Volts orM A ,

AC volts or OHMS and the BATT. CHK.

RANGE SWITCH: The RANGE switch s ele c ts the d esired range of cu rren t,

voltage,

or re s is ta n c e

to be measured.

SHIELDED LEAD ON THE F E 14 & FE16

The Sencore

Field E ffect M eters are equipped with a shielded lead cm .the positive

input

lead so

that accu rate AC m easurem ents

can be

made in

the p resen ce of

strong electro static and

magnetic

fields.

The

shield,

which is

also effective on

high ohms ranges, is only connected when using the AC Volts/Ohms functions and

is disconnected when making			DC m easurem ents to prevent capacitive loading of
the c irc u it being measured.
T e s t lead connections to		the	FE 14	or F E 1 6	are made through the red and black
banana ja c k s .	The shield	connects		through a	sm all pin ja c k (plainly marked) so
that it cannot be m istakenly used as one of the					test lead connections.
OPERATING THE FE 14 and FE16
The Sencore	Field E ffect M eters are			sim ple and easy to operate. Set the Function

switch to the desired test to be preformed, the RANGE switch to the d esired range, connect the leads and read the resu lts on the m eter. Here is a b rief description of how each test is perform ed.

READING DC VOLTS: To read DC volts, the Function switch is set to either plus or minus DCV/MA. The Range switch is s e t to the desired range of voltage fro m

one volt' to 1000 volts full scale .

If the voltage to be

m easured is unknown,

start

with the highest range and work down until the voltage can be m easured .

Connect

the leads to the circu it and read the re su lts on the m eter.

When m easuring voltage

in R F - I F circu its, a 100K

isolation r e s is to r at

the

end of the

red test

lead will

reduce capacitive effects without effecting a ccu ra cy

of readings.

T he

DC voltage is read on the two black s c a le s ju st above the

m irr o r

on the m eter.

The

top DC

scale

is from zero

to 1 . 0 volts and

each

m ark is

equal

to

. 0 2

volts.

Thebottom

scale

is zero to 3. 0 volts and each m a r k is

equal to

. 1 volts.

The zero

to 1 . 0 scale is usedfor

the 1, 10, 100, and 1000 volt

ranges

and the

zero to 3 .0

scale is used for

the 3,

30,

and 300 volt ran ges.

In use

the

m eter

indication

is

multiplied

by 10,

100,

or

1000

depending upon

the

range.

F o r example,

if

the

range

switch is on the

10 volt range

and the m eter re a d s

. 42 volts,

the actual vol­

tage is

. 42 tim es

10 or 4. 2 volts

DC.

READING AC VOLTS:

To read AC volts, the Function switch is set to the ACV/OHMS

position and the Range

switch

to the

d esired

range.

F o r RMS

voltages

the

two

black s c a le s marked

AC (RMS) a re

used.

F o r peak to peak voltages,

the two red

s c a le s d irectly below the AC (RMS) s c a le s

a re

used.

T h e readings are

multiplied

in the sam e way as with

the DC s c a le s,

to obtain

the actual

voltage

present.

On

the zero to 1 . 0

AC (RMS)

scale,

each m ark is

. 02

volts and on the zero to 3. 0 volts

s ca le,

each m ark is

. 1 volts.

On the zero

to 2. 8 volts AC (P-P)

scale,

each m ark

is . 1 volts

and on the z e ro to 8. 4 volts

scale,

each m ark

is

. 2 volts.

READING DC VOLTS ZERO CEN TER

SCA LE:

The z e ro

cen ter sca les are used to

read plus or minus

voltages

without

the

n ecessity of

changing polarity

with

the

leads or Function switch.

To

use the zero cen ter

s c a le s ,

set

the Function

switch

to plus DCV/MA position and

adjust

the ZERO ADJ until

the

m eter

read s at

the

z e ro m ark in the cen ter of the

sca le .

This gives ran ges of plus or minus

. 5 volts

(top scale) or plus or minus

1. 5 volts

(bottom scale)

tim es

10,

100, or

1000 d e ­

pending upon the setting of the range

switch.

If the range

switch is in the 300 volt

position, the zero

to 1. 5 volts

sca le

is

used and becom es

z e ro

to 150 volts plus or

minus.

If

the m eter

swings

up

sca le

or to

the right,

it is a positive voltage.

If

the m eter

swings

down scale

o r

to the

left,

it is a negetive

voltage.

This

unique

feature allows you to determ ine

the polarity as well as

the amplitude of a DC vol­

tage and is very handy in solid state servicing .

READING OHMS:

To read re s is ta n c e ,

set

the Function switch to ACV/OHMS and

the Range switch to the desired

range of re s is ta n c e to be read .

After checking to

s ee that the m eter

is

"zero ed "

at the

left edge of the s ca le,

short

the leads

together

and adjust the OHMS ADJ control

for

full

scale deflection of

the m eter.

Unshort

the leads and be sure

that the m eter

retu rn s to the extrem e left of the

scale .

Place

the unknown resista n c e between the two leads

and read

the resista n c e

on the Gil VIS

sca le (top

red

scale

on m eter).

Multiply

the reading

on the

m eter by

the range

used.

F o r

exam ple,

if the m eter read

15 and the range switch was set on RX100,

the actual r e s is ta n c e

would be 15 tim es

100 or

1500 ohm s. CAUTION: When m ak­

ing ohm s m easurem ents,

be sure

that the power to the c ir c u it is

turned off.

The

application

of e x c e ss iv e

voltages to the RX1,

RX10,

and RX100 ohms ranges can

damage

the internal standard

r e s is to r

of the

Field

E ffec t M eter.

MEASURING DC CU RREN T:

To

m easu re DC cu rren t,

the Function switch is set

to eith er the plus or minus DCV/MA position and

the Range

switch to the desired

ran ge of cu rren t.

The power to the Field E ffect M eter

does

not have to be turned

on and

may be

left off

to con serv e on

battery life

if you so

d esire .

Connect

the

leads in s e r ie s

and

read

the

resultant

cu rren t on the

m eter.

The

0 to

1 . 0

DC

VO LTS (MA) s ca le is

usedon all c u rren t m easu rem en ts.

If the m eter read s back­

wards,

indicating that the leads a r e rev ersed ,

sim ply change

the polarity with the

Function switch to the opposite polarity and the m eter

will read up scale .

MEASURING HIGH VOLTAGE WITH THE F E 14 AND F E 16

CAUTION:

High voltage is dangerous and caution should

be observed when m ea-

suring high voltages.

Be sure

that the ground lead from the Field E ffect M etei

is

connected

to the ground on the

unit.

If

the ground lead is

not connected,

you θ ίβ

m e r e ly extending the high voltage c lo s e r to you.

Stand away from the unit you a re

m easuring and keep one hand in your pocket as a safety m easu re .

High voltage

(Π

colo r T V is esp ecially dangerous

because it can go as

high as

30, 000 volts

and IS

regulated .

If you should com e

a c r o s s

it, it will not load down.