Fluke III Series User manual

79/26 English Instruction Sheet
Page 1
®
79/26
Series III Multimeter
Instruction Sheet
W Read First: Safety Information
•Never use the meter if the meter or test leads look damaged.
•Be sure the test leads and switch are in the correct position
for the desired measurement.
•Never measure resistance in a circuit when power is applied.
•Never touch the probe to a voltage source when the test
leads are plugged into the 10 A or 40 mA input jack.
•Never apply more than rated voltage between any input jack
and earth ground.
•Be careful when working with voltages above 60 V dc or 30
V ac rms. Such voltages pose a shock hazard.
•Keep your fingers behind the finger guards on the test
probes when making measurements.
WWarning
To avoid false readings, which could lead to
possible electric shock or personal injury, replace
the battery as soon as the battery indicator M
appears.
Symbols
WRead First: Safety Information
YDangerous Voltage May Be Present
TDouble Insulation
Overvoltage Installation Category per IEC 1010:
CAT II
CAT III
Typical locations include main wall outlets, local
appliances, and portable equipment.
Typical locations include switches in the fixed
installation and equipment for industrial use
permanently connected to the fixed installation.
PN 687589 August 1997 Rev. 2, 4/98
1997, 1998 Fluke Corporation. All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies.

79/26 English Instruction Sheet
Page 2
Input Jacks
V
600V
1000V
FUSED
CAT
CAT
Volts, Ohms,
Diode Test
Common Terminal
Amp
Milliamp
jo1f.eps
See Specifications for overload protection.
Ranging
The meter defaults to autorange when you turn on the meter.
Manual ranging is available in V ac, V dc, Hz, ohms,
capacitance, A ac, and A dc.
RANGE
CAT
CAT
+
_
RANGE
MANUAL
MANUAL
Momentary
jo11f.eps
To return to autorange, press for 1 second or turn the
rotary switch.
Bar Graph
The bar graph shows readings relative to the full scale value of
the displayed measurement range and indicates polarity.
_
+
0 2001 400 2 600 3800 41000
mV
jo19f.eps

79/26 English Instruction Sheet
Page 3
Automatic Touch Hold  Mode
WWarning
To avoid electric shock, do not use the Touch
Holdmode to determine if a circuit with high
voltage is dead. The Touch Holdmode will not
capture unstable or noisy readings.
The Touch Holdmode automatically captures and displays a
stable voltage reading.
Single Beep
RANGE
CAT
+__
RANGE
CAT
CAT
+_
RANGE
CAT
CAT
+
HOLD
HOLD
HOLD HOLD
HOLD
V V V
jo4f.eps
When the meter detects a new input, it beeps and displays a new
reading.
Stray voltages can cause the meter to display a new reading.
To exit the Touch Holdmode, press the yellow key a second
time or turn the rotary switch.
Smoothing Displayed Readings
Smoothing displays the average of eight readings. When the
input signal changes rapidly, smoothing makes the digital display
readings more stable. Smoothing does not work in continuity, Lo-
Ohms, and capacitance.
To select Smoothing, press the yellow key while turning on the
meter.

79/26 English Instruction Sheet
Page 4
Standby
If the meter is on but is inactive for an hour (20 minutes in diode
test), the screen only displays four bar graph segments. To
resume operation, turn the rotary switch or press a button.
AC and DC Voltage (KLmL)
RANGE
CAT
+__
RANGE
CAT
CAT
+_
RANGE
CAT
CAT
+
Volts AC Volts DC Millivolts DC
VVmV
jo3f.eps
In the mV dc function, the meter defaults to 400 mV. To enter the
40 mV range, press momentarily.
Frequency (Hz)
The bar graph indicates the ac voltage present.
WWarning
To avoid electric shock, disregard the bar graph
when frequency is > 1 kHz. If the frequency of
the measured signal is > 1 kHz, the bar graph
voltage is unspecified.
Hz
RANGE
CAT
CAT
+_
Hz
_
+
mV
jo20f.eps

79/26 English Instruction Sheet
Page 5
Resistance (e)
Turn off the power and discharge all capacitors. An external
voltage across a component will give invalid resistance readings.
RANGE
+_
jo7f.eps
Diode Test (G)
RANGE
+__
Forward Bias
Single Beep
RANGE
CAT
+
Reverse Bias
Good Diode Good Diode
_
RANGE
CAT
+
Shorted
and
Bad Diode
Open
_
RANGE
CAT
+
Bad Diode
40 40
40 40
jo5f.eps
Press 1 second to turn the beeper off.

79/26 English Instruction Sheet
Page 6
Lead Resistance Compensation
This function compensates for resistance in the leads and the
meter’s internal protection circuitry. You can compensate in
either Lo-Ohms or continuity.
RANGE
CAT
CAT
+_
RANGE
CAT
+_
RANGE
CAT
CAT
+_
RANGE
1 second
40 40 40
jo17f.eps
When zero is displayed, compensation has occurred. The meter
stays compensated until you change functions.
Lo-Ohms (40 e)
The Lo-Ohms (40 Ω) function improves noise rejection and
resolution, but is less accurate than the ohms function. In this
function, the beeper is turned off.
RANGE
+_
RANGE
1 Second
40
jo6f.eps
To compensate for the lead resistance, see “Lead Resistance
Compensation.”

79/26 English Instruction Sheet
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Continuity Test ( R)
RANGE
CAT
+_
RANGE
CAT
CAT
+_
40 40
jo8f.eps
Opens or shorts > 1 ms are detected. Press momentarily
for lead compensation. Press 1 second to turn the
beeper off and place the meter into Lo-Ohms autoranging.
Capacitance (E)
Turn off the power and discharge the capacitor. If the capacitor
requires more discharging, diSC displays while the capacitor
discharges.
RANGE
+_
+
jo18f.eps
For rated accuracy in the lowest two capacitance ranges,
subtract the open-lead reading from the measurement.
Current (?A)WWarning
To avoid injury, do not attempt a current
measurement if the open circuit voltage
exceeds the rated voltage of the meter.
To avoid blowing an input fuse, use the 10 A jack until you are
sure that the current is less than 40 mA.

79/26 English Instruction Sheet
Page 8
Turn off power to the circuit. Break the circuit. (For circuits of
more than 10 amps, use a current clamp.) Put the meter in series
with the circuit as shown and turn power on.
RANGE
_
CAT
CAT
+
+
1
2
4
3
A
AC
jo10f.eps
Probe Holder
jo21f.eps
Maintenance
WWarning
To avoid electric shock, remove the test leads
before opening the case, and close the case before
using the meter. To prevent fire and possible arc-
flash, use fuses with ratings shown on the back of
the meter.
Caution
To avoid contamination or static damage, do not
touch the circuit board without proper static
protection.
Internal Fuse Test
RANGE
10 A40 mA Ω
<.5
Ω
10-12 OKOK OK
OK
jo9f.eps

79/26 English Instruction Sheet
Page 9
Battery and Fuse Replacement
Note
Before opening the case, make sure the test leads are
removed and the rotary switch is turned to OFF.
F2
F1
jo14f.eps
Cleaning
To clean the meter, use a damp cloth and mild detergent; do not
use abrasives or solvents on the meter.
Service and Parts
To contact Fluke, call one of the following telephone numbers:
USA and Canada: 1-888-99-FLUKE (1-888-993-5853)
Europe: [phone]
Japan: [phone]
Singapore: +65-*-276-6196
Anywhere in the world: [phone]
Or, visit Fluke’s Web site at www.fluke.com.
Item Description Fluke PN Quan.
BT1 Battery, 9 V Alkaline (NEDA 1604A/
IEC 6LR61) 614487 1
F1* Fuse, F44/100 A, 1000 VAC/DC
Min Interrupt Rating 10 kA 943121 1
F2* Fuse, F11 A, 1000 VAC/DC,
Min Interrupt Rating 17 kA 943118 1
* For safety, use exact replacement
True RMS and Crest Factor
True rms sensing provides accurate readings on sinusoidal
signals and on signals with harmonics or distorted waveforms.
True rms readings indicate the true heat-providing current which
may cause overheated conductors, connections, breakers, or
transformers.
Crest factor (CF) is the peak signal value divided by the rms
signal value and defines the dynamic range of the meter. A sine
wave has a CF = 1.4.

79/26 English Instruction Sheet
Page 10
Specification
Accuracy specifications:
±([% of reading] + [number of
least significant digits])
1 year, 18°C to 28°C (64°F to 82°F)
≤90% RH
Display Digital: 4000 counts, updates 4/sec
Analog: 63 segments, updates 40/sec
Frequency: 9,999 counts
Capacitance: 9,999 counts
Response Time of Digital
Display V ac < 1.5 s V dc < 1 s
Ω<1 s to 40 kΩ, <2 s to 4 MΩ, <10 s to
40 MΩ
Operating Temperature 0°C to 55°C
Storage Temperature -40°C to 60°C
Temperature Coefficient 0.1 x (specified accuracy)/°C
(<18°C or >28°C)
Relative Humidity 90% (0°C to 30°C)
75% (30°C to 40°C)
45% (40°C to 50°C)
35% (50°C to 55°C)
Altitude Operating: 2000 meters
Storage: 12,000 meters
Battery Type 9 V, NEDA 1604A or IEC 6LR61
Battery Life 500 hrs typical with alkaline
Continuity Beeper 4096 Hz
Vibration per MIL-T-PRF 28800F Class III,
Sinusoidal, Non Operating
Drop I meter drop per IEC 1010-1
Enclosure Conforms to IP-40 per IEC-529
Size (H x W x L) 3.7 cm x 8.9 - 7.8 cm x 19 cm
(1.5 in x 3.5 - 3.1 in x 7.49 in)
Weight 365 g (12.9 oz)
Electromagnetic Compatibility V ac and A ac only: RF field = 3 V/m.
Total accuracy = specified accuracy +
2.0% of range. EN 61326-1: 1997
Surge Protection 6 kV peak per IEC 1010-1, 1990-09
Safety 600 V CAT III and 1000 V CAT II per
ANSI/ISA-S82.01-94, UL3111-1,
CSA/CAN C22.2 No 1010.1-92,
EN 61010 part 1:1993.
Certification