INSTRUCTION MANUAL
Digital Multimeter
Model 178
SPECIFICATIONS
DC VOLTAGE
RANGE
2OV
200 v
1200v
ACCURACY (12 months)
18°-28°C
±(% rdg + digits)
MAXIMUM
READING
1200V momentary
1200v
1200v
1200v
0.04% + 1d
1.9999
19.999
0.04% +1Id
0.04% +1Id
0.04% +1Id
199.99
1200.0
Temperature Coefficient (0°-18° and 28°-55°C):
Normal Mode Rejection Ratio:
G r e a t e r t h a n 6 0 d B a t 50Hz and 60Hz.
+(0.006% + 0.2 digit)/°C
Common Mode Rejection Ratio (lkfi unbalance):
Input Resistance: 10 M Q ± 0 . 1%
Settling Time: 1 s e c o n d t o w i t h i n 1 d i g i t o f
final
MAXIMUM
ALLOWABLE INPUT
G r e a t e r t h a n 1 2 0 d B a t D C , 50Hz and 60Hz.
reading.
AC VOLTAGE
RANGE
2 v
20 v
200 v
1000 v
MAXIMUM
READING
ACCURACY (12 months)
(above 2000 counts)
1 8 ° - 2 8 ° C ; 1 00Hz-1 Ok Hz
±(% rdg + digits)
TEMPERATURE COEFFICIENT
0°-I 8° and 28°-55°C
±(% rdg + digits)/°C
45Hz-10kHz
I0kHz-20kHz
0.4% + 15d
1.9999
19.999
199.99
1000.0
0.04%
0.01%
0.01%
0.01%
0.3% + 15d
0.3% + 15d
0.3% + 15d
Extended Frequency Accuracy:
Input
(45Hz-100Hz) ±(0.5% + 1 5 d i g i t s )
(10kHz-20kHz) ±(1.0% + 1 5 d i g i t s )
Response: A v e r a g e r e s p o n d i n g c a l i b r a t e d i n r m s
of a sinewave.
Settling Time: 2 . 5 s e c o n d s t o w i t h i n 1 0 d i g i t s
of final reading.
+
+
+
+
0.09%
0.03%
0.03%
0.03%
0.5d
0.5d
0.5d
0.5d
+ 0.5d
+ 0.5d
+ 0.5d
+ 0.5d
Impedance:
IMfi + 1% shunted by less than 75pF.
Maximum Allowable Input Voltage:
1000V
rms,
1400V
p e a k , 107V·Hz
maximum.
Common Mode Rejection Ratio (lkfi unbalance):
6 0 d B a t D C , 50Hz a n d 60Hz.
RESISTANCE
RANGE
MAXIMUM
READING
2kQ
1.9999
20 kQ
19.999
200 kQ
2000 kQ
20Ma
199.99
1999.9
19.999
ACCURACY (12 months) TEMPERATURE COEFFICIENT
18°-28°C
0 ° - 1 8 ° and 2 8 ° - 5 5 ° C
±(% rdg + digits)
±(% rdg + digits)/°C
0.04% + 2d
0.04% + I d
0.04% + I d
0.04% + I d
0.10% + 1 d
M a x i m u m A l l o w a b l e I n p u t : 250V rms sine, 350Vpeak.
Maximum Voltage Across Unknown: 2V within range,
0.003%
0.003%
0.003%
0.003%
0.02 %
+
+
+
+
+
0.2d
0.2d
0.2d
0.2d
0.2d
NOMINAL
APPLIED CURRENT
1mA
100~ A
10~ A
1P A
0.1~ A
Settling Time: 1 s e c o n d t o w i t h i n 1 d i g i t o f f i n a l
r e a d i n g e x c e p t 2 s e c o n d s o n t h e 20Mfi
range.
5V open circuit.
GENERAL
POWER:
DISPLAY:
Five 0.5” LED digits, appropriate
position and polarity indication.
CONVERSION PERIOD: 400 milliseconds.
decimal
ENVIRONMENT:
Operating: 0 ° C
Storage:
AA
to 55°C;
0% to 80% relative humidity up to 40°C.
- 2 5 ° C t o +65°C.
105-125 or 210-250 volts (switch select e d ) , 9 0 - I 10V a v a i l a b l e . 50-60Hz, 7 watts.
Optional 6 hour battery pack, Model 1788.
DIMENSIONS, WEIGHT: 85mm high x 235mm
w i d e x 2 7 5 m m d e e p (3-1/2 in. x 9-1/4 in. x
10-3/4 i n . ) . N e t w e i g h t : 1.7kg (3lbs., 13 oz).
OVERRANGE INDICATION: Display blinks all
zeros above 19999 counts.
MAXIMUM COMMON MODE VOLTAGE: 1400V peak.
OPERATING
INSTRUCTION MANUAL
INSTRUCTIONS
Digital Multimeter
Model 178
2-7
7.
OPERATING
Refer to Figure 2-3 and operate the
INSTRUCTIONS.
a.
Turn on the power by depressing the ON/OFF
b
Select
l
DMM
as
follows:
pushbutton.
the function with the DCV, ACV or 52
pushbutton.
For ac and dc voltage
Select the range by depressing the appropriate pushbutton.
c.
For resistance measurements there are
measurements there are four ranges available.
The pushbuttons are interlocked to avoid improper settings.
five ranges.
d.
Connect
the
source
to
the
INPUT
terminals.
POLARlTY (NEGATIVE IS INDICATED, POSITIVE IS IMPLIED WHEN MINUS (-) DISPLAY IS OFF)
DCV
ACV
ELECT FUNCTION
* A D J U S T ZERO AS REQUIRED
FOR
MEASUREMENT
2-3.
FIGURE
SELECT RANGE
OF
DC
VOLTAGE
Operating
AND
CONNECT-SOURCE
RESISTANCE.
SEE SEC. 2-11.
Controls.
CAUTION
MAXIMUM
DCV:
RATINGS: n
(2V): 45OV
rms
continuous;
(20-1200V): 12OOV
ACV:
(All
a:
(All
Ranges):
Ranges):
12OOV
peak, for
8 seconds
peak.
1OOOV
rms; 10 7V·Hz.
25OV rms sine wave or 35OV
peak.
per
minute.
2-8 .
a.
DC VOLTAGE
Turn
on
Use the Model 178
MEASUREMENT.
power
and
depress
the
DCV
DMM to measure
dc
volts
as
follows:
pushbutton.
Select the desired range from the four ranqes available. The maximum reading
Over range is indicated by a flashing 0000 except on the 1OOO-volt range.
19999.
b.
is
CAUTION
1. Do
n
not
exceed
Neqative polarity
C.
t h e m i n u s (-) d i s p l a y i s
the
maximum
is displayed
off.
Instrument
ratings.
Positive
automatically.
Zero the instrument as described in Paragraph 2-11
d
the’instrument is used outside the temperature range of
weekly ,during normal use.
2-9 .
a.
AC
VOLTAGE
MEASUREMENT.
damage
may
polarity
occur.
is
before the first
to 28°C, and
18"
implied
when
use, whenever
approximately
Use the Model 178 DMM to measure ac volts as follows:
Turn on power and depress the ACV pushbutton.
CAUTION
I.
A
Do
not
exceed
the
maximum
ratings.
Instrument
damage
may
occur.
Select the desired range from the four ranges available.
The maximum reading is
The
Overrange
is
indicated
by
a
flashing
0000
except
on
the
lOOO-volt range.
19999
instrument reads the root mean square value of a sine wave with a frequency of 45 to 20
kHz.
b
The Model 1682 RF Probe (see Paragraph
c.
with a frequency of 20kHz to 100MHz.
2-10.
RESISTANCE
Turn
on
(R)
power
MEASUREMENT.
and
2-12e) should
.
Use the 178 DMM
depress the Sz
to
be
used
measure
to
measure
resistance
as
ac
voltages
follows:
pushbutton.
CAUTION
1. Do
n
not
exceed
the
maximum
ratings.
instrument
damage
may
occur.
b
Select the desired range- from the five ranges available.
The maximum reading is
Overrange is indicated by a flashing 0000.
The letter k refers to kilohms, and
19999
M refers to meqohms.
c.
The HI
junctions.
d .
input terminal
is positive
and
causes
Two volts is applied at full range with 5
forward
volts
conduction
maximum
under
of
open
semiconductor
circuit
conditions.
Zero
the
i n s t r u m e n t as d e s c r i b e d
in Paragraph 2-11 before the first use whenever
theainstrument i s u s e d o u t s i d e t h e t e m p e r a t u r e r a n g e o f 18° to 28°C,
and
approximately
weekly during normal use.
ZERO ADJUSTMENT.
2-11.
The zero adjustment nulls input offset on the 20, 200 and 1200
volt ranges and on all resistance ranges.
Typically, this adjustment need not be performed more often than once a week unless the instrument is operated at ambient
t e m p e r a t u r e s o u t s i d e t h e r a n g e o f 18° to 28°C.
Zero adjustment may also be used for lead
compensation on the Q function.
Zero the instrument as follows:
a.
Turn
on
the power and
select
DCV
and the
20
range.
b. Plug in test leads and short them.
A d j u s t t h e z e r o a d j u s t ( p o t R132) f r o m
front panel with a small screwdriver to obtain a reading of 0000 or - 0 0 0 0 .
the
2-12.
ACCESSORIES.
A wide range of accessories is available to facilitate
DMM, extend its range and adapt it for additional uses.
M o d e l 178
of
use
the