Conrad M 3860-M User manual

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1. Introduction
This Mulitmeter is equipped with several special features and useful fun-
ctions which are indispensable for electrical and electronic measure-
ment: back-light, illuminates display in poor lighting conditions during
measurement, or the quadro-display, a multiple display with four simul-
taneous reading outputs e.g. during “POWER“ measurement display of
real power input, current input of the consumer, AC voltage and power
factor (Cos Phi).
AUTO RANGE always selects the correct measuring range, to archieve
best accuracy. The function REL allows the operator to measure value
with respect to a preset reference value, in the secondary displays the
Offset is shown, the deviation in ± % and the preset reference value and
the main display shows the present measuring value. With the function
CMP, comparative measurement can be made, the upper and the lower
limit can be defined. With the function MEM (for Memory = store) and
RCL (for Recall), 10 measurements can be stored in memory and recalled.
AUTO-POWER-CUT-OFF extends the life of the battery by turning off the
meter (Stand-by) if neither the rotary function switch nor a button is
operated for 12 minutes.
The DMM can be used for hobby, industry (with restrictions) and school.
etc.
2. Safety Rules
•The multimeter M-3860M is EMC-tested and corresponds to the fol-
lowing EG-standard: 89/336/EWG
•This unit is constructed and checked according to DIN 57 411
Part 1/VDE 0411 Part 1, Safety Requirement for Electronic Measuring
Units. This unit left the factory in safe and perfect condition. To main-
tain the unit in this condition and to guarantee a safe operation, the
user must observe the safety rules and warnings which are contained
in this manual, by all means.
•This multimeter may only be used in fuse lines which are protected
with 16 A. The voltage existing/appearing must not exceed 250 VDC/
VAC and the maximum load must not exceed 4000 VA. It is not allo-
wed to use the unit for installations in the overload range III according
2
Digital-Multimeter M 3860-M
Order No.: 12 39 00
The proper operation of the measuring unit includes:
•measurement of DC voltage up to 1000 VDC max.
• measurement of AC voltage up to 750 VAC.
• measurement of DC and AC current to 20 A (fused)
• measurement of resistance to 40 MΩmax.
• measurement of capacitance of 400 µF
• continuity check, diode and transistor test, logic test
• measurement of frequency to 40 MHz max.
• measurement of temperatures from -40 °C to +1200°C max.
• CMOS-signal output to 10.24 KHz in 10 steps
• it is not allowed to operate the unit in wet or damp environment!
• any other usage as described above is forbidden
Attention!
Read before Operation!
Read this manual carefully and completely. In the case of damage cau-
sed by non-observance of the instruction, the claims under guarantee
lapse. No legal liability can be accepted for any damage from the multi-
meter being used for the wrong purpose or operated improperly. We
cannot take any liability for consequential damage.
Contents Page
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Safety Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Description of the Control Elements . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Usage of the Multimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6. Maintenance and Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7. Technical Data and Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
GB

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Such voltage might cause a life-dangerous electrical shock when elec-
trical conductors are touched.
First switch off voltage source, connect the measuring unit with the
terminals of the voltage source to be measured, set the measuring
unit to the necessary voltage range and afterwards switch on voltage
source.
After measurement has been finished, switch off the voltage source
and remove the measuring cables from the terminals of the voltage
source.
•Make sure before each voltage measurement the unit is not set to the
amperage range.
• Before changing the measuring range remove the probe tips from the
object to be measured.
• Control before each measurement the measuring unit and your test
leads to make sure they are not damaged.
•Do not use this measuring unit in environments or rooms with adver-
se environmental conditions where flammable gases, steams or dusts
exist or may exist. For your own safety avoid under all circumstances
that the measuring unit or the test leads become damp or wet.
Avoid the usage near
a) strong magnetic fields (loudspeakers, magnets)
b) electromagnetic fields (transformers, motors, coils, relays, contac-
tors, electromagnets etc. )
c) electrostatic fields (charge/discharge).
d) transmission antennas or hf-generators
•For measurement use only those test leads which are supplied with
the measuring unit. Only these are admissible.
• To avoid an electrical shock, don’t touch directly or indirectly the test
probes and the test points during measurement.
• To avoid serious electrical shock and/or instrument damage do not
apply more than 500 VDC/VACrms between any terminal of the mea-
suring unit and the earth ground.
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to IEC 664. The unit and the measuring cables are not protected
against arcing (IEC 1010-2-031, section 13.101).
• Keep children away from measuring units!
•Pay attention to the rules for prevention of accidents in industrial
enterprises prescibed by the Industrial Trade Associations for Electrical
Installations and Production Facilities.
•When using the unit in schools and hobby-workshops the usage and
the measurement has to be controlled by the responsible teachers or
skilled personell.
•If covers are opened or parts are removed, except it is possible with-
out tools, voltage-carrying components may be accessable. Terminals
can also carry voltage. If it is necessary to open the unit before adjust-
ment, maintenance, repairing or exchange of parts or modules, the
measuring unit has to be separated from all voltage sources and mea-
suring circuits. Repairs or maintenance to the measuring unit must
only be carried out by qualified service personell or qualified electrici-
ans who know the dangers and the respective rules (VDE 0100, VDE-
0701, VDE-0683).
•Capacitors in the unit can still carry voltage, even if the unit has been
separated from all voltage sources.
•Please make sure to use new fuses of the proper rating. Do not use
repaired fuses and do not bridge the fuse holders.
To replace the fuse separate the measuring unit from the measuring
circuit, remove any input signal and switch it off. Remove all connec-
ted cables and probe tips. Use a suitable crosspoint screw driver
carefully open the case. Remove the defective fuse(s) and replace it
with a new one of the same type and nominal current 0.8 A quick blow,
250 V; usual name: F 0.8 A/250 V or F 800 mA/250V. For the amperage
range 20 A ultra rapid, 250 V; usual name: FF 20 A/250 V (BUSS ABC20).
After the fuse has been exchanged close the cabinet. Do not operate
the unit before it has been closed and screwed safely.
•Use special caution when working with voltage above 25 V (AC) and
above 35 V (DC).

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6. DOWN Button
This key is needed in the manual range mode to select the next lower
range.
7. Display Back Light
Press button short and several small LEDs illuminate the display-
background, it is sufficient to read display even in poor lighting conditions.
8. Transistor Socket
This socket is for testing the hfe-parameter of different semiconduc-
tors (except power transistors and FETs, triacs and thyristors).
9. Capacitance and Temperature & Signal Output, Input Socket
This socket is for testing discharged! capacitors or temperatures.
10. Rotary Function Switch to select the different modes (voltage and
current measurement, etc.)
11. 20-A Input Socket
This input socket is designed for measuring DC and AC current to
max. 20 A and is fused with 20 A.
12. mA-input
This socket is for measuring DC and AC current to 400 mA max.
13. COM-Input Socket (COM or Minus Terminal)
14. V-Ohm-(+) Input Socket (Plus Terminal)
15. Liquid Crystal Display (LCD) (3 3/4digit, max. display value 4000)
16. Analogous Bargraph
17. Bargraph-Segments
Figure see folding page
18. Overload “OL“-Indication
“OL“ is displayed and an acoustic signal is emitted when the range is
exceeded = overflow (no acoustic signal during resistance measure-
ment, diode test or temperature measurement).
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•If there are doubts whether a safe usage is still possible the unit has
to be put out of operation and be secured against unintentional use.
It must be assumed that a safe usage is not possible if
- the unit shows visible damage
- the unit does not work and
- longterm storage under unfavourable conditions
or
- transport strain took place
• Don’t switch on the measuring unit immediately after bringing it in
from a cold to warm room. Condensed water might impair or destroy
your unit. Give the unit time to warm up to room temperature with-
out switching it on.
3. Description of the Operation Elements
Picture see folding page
1. Power ON/OFF
2. Push Button for Function
With this key you can set the different sub-function as, MIN/MAX,
REL, CMP etc.
3. Set/Reset Button “SET/R“
With this key the unit is reset, the selected function mode is exited.
In certain function modes the Reset function does not work!
4. DC OHM /AC Push Button
Press this button to toggle between DC and AC when function switch
is set to voltage or current, or when function switch is set to resi-
stance to change between resistance measurement to (acoustic) con-
tinuity check.
5. UP Button
The key is needed in the manual range mode to select the next
higher range.

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33. CAP = Capacitance
CAP is for Capacitance => Measurement of capacitors
34. hFE
This symbol indicates the transistor test.
35. LOGI = Logic Test
This symbol indicates the Logic Test Function
36. 1. 2. and 3. Sub-Display
These three small sub-displays with 3 3/4digits are activated during
the different function modes.
37. = Low Battery
When this symbol is displayed, it is time to change the battery
38. Different Units of the Display Values
4. Usage of the Multimeter
4.1 Inserting the Battery - Battery Exchange
To guarantee precise measurement, insert a standard 9 V battery. If the
battery symbol appears in the display, it is time to change the battery.
Proceed as follows:
•Disconnect your measuring unit from the measuring circuit, disconnect
the test-leads from the measuring unit and turn off the power.
Remove with a crosspoint screw driver the fastening screw to open the
battery compartment. Now lift the cover carefully (use a small screw
driver).
Separate the old battery from the battery snap and fasten a new one
of the same type. Do not forget to use the provided battery insulation
capsule.
After the battery has been changed reinsert the battery into the bat-
tery case and close it carefully, secure it with the screw.
+-
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Attention!
Observe the max. input limits.
19. Data Hold D-H
Data Hold means the meter will “freeze“ a display reading.
20. REL = Relative = Reference Value
21. CMP = Comparison = Compare a Reading
22. R-H = Range Hold
= Holding the current preset measuring range e.g. 40 KOhm
23. A-H = Auto Hold
= Min-, Max- and AVG-holding with simultaneous display
24. MEM = Memory
= to memorize the value
25. RCL= Recall
= to get back the memorized reading on the display.
26. Reference No. (0 to 9)
27. = Diode Test
28. AC = Symbol for AC current or voltage
29. = Symbol for Acoustic Continuity Check
30. “- “= Minus Sign or Symbol for Negative Polarity
31. FREQ = Frequency
This symbol is displayed in the Frequency Count Mode
32. TEMP = Temperature
This symbol is displayed during temperature measurement.

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4.4 Operation
4.4.1 Basic Settings
Hint!
The numbers which are put in brackets in the following text refer to
“Description of the Operation Elements“, point 3.
Press the button “ON“ (1). Turn the rotary function switch to the desired
position. Now the meter is ready for “normal“ operation without addi-
tional function. Even without additional functions “small“ displays (sub-
displays) support measurement.
To select an additional function press the key FUNCTION (2). Press it
again to scroll through the different sub-functions.
To exit the menu press SET/R-key twice: press SET/R-key once to enter,
press button twice to exit/reset (depending on the preset sub-function).
4.4.2 Terminal and Switch Imprint
a) Press the ON/OFF-key (1) to turn the unit on and off: Press the key
once to turn the power on, press it again to turn the DMM off.
AUTO-POWER-CUT-OFF extends the life of the battery: if neither the
rotary function switch nor a button is operated for 12 minutes the
DMM is automatically turned off. During “communication“ of the
multimeter with a PC, i.e exchange of data, AUTO-POWER-OFF is dis-
abled.
b) FUNC
Press this button to select the function modes. The following symbols
appear in the display when you scroll in the function modes:
D-H -> R-H -> A-H -> REL -> MEM -> RCL -> CMP
c) SET/R
Press this button once to activate or to enter the selected function
mode.
• Press in the function mode the button D-H again to exit (wait for
beeper sound).
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Attention!
Never use the measuring unit before the cover has been closed comple-
tely, to avoid an electrical shock!
Never leave empty batteries in the measuring unit, as even corrosion-
free batteries might leak and chemicals could be released, which are
detrimental to your health and disturb the battery compartment.
Please remember batteries - due to their heavy metal content - are no
ordinary refuse. They must be disposed of in special containers or in a
safe manner that complies with all applicable laws.
4.2 Connection of the Measuring Cables
For measurement use only the type of test-leads which are supplied with
your measuring unit. Only these are admissible. Ensure the connection
plugs and test probes are in good condition before usage, pay attention
that the insulation is undamaged.
These test-leads are rated for max. 1200 V. The maximum rating of the
multimeter M-3860M is 1000 VDC max or 750 VACrms. Use special cauti-
on when working with voltage above 25 V AC and above 35 V DC.
Attention!
To avoid the risk of electrical shock, instrument damage and/or equip-
ment damage, input limits must not be exceeded.
4.3 Using the Stand
Your meter has a stand on the rear side for bench use which can be
opend away from the meter. You can prop the unit for improvement of
reading.

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sistor socket as in the drawing according to transistor type, remove
voltage before measurement.
b) Capacity- and Temperature Measuring Socket (poles “+“ and “-“)
In this socket discharged capacitors can be checked, observe correct
polarity. Make sure the connector pins are long enough to avoid
unreliable measurement.
For temperature measurement plug in type “K“ temp probes (NiCrNi),
observe the correct polarity.
Plug in adapter for function „SIG OUT“.
Attention!
The outer contacts are only for capacitance measurement, the inner
contacts are only! for temperature measurement & signal output
checking. Never confuse the sockets to avoid damage of the meter.
c) Rotary Function Switch = Measuring Function Switch (10)
Attention!
Never turn the rotary function switch during measurement, as there is
the risk of instrument damage and danger to life.
The different basic measuring ranges are selectable by turning the switch
(clockwise).
SIG OUT = CMOS signal output - no function mode possible
mV = millivolt AC/DC (milli = 10 exp. -3) no manual range selction
V = Volt AC/DC - Auto-Range and manual range selection (R-H)
is possible
FREQ = frequency measurement - Auto Range and manual range
selection (R-H) is possible
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• In the function mode R-H simply press button again to exit.
• In the function mode A-H (MIN-MAX and AVG) the R-H symbol (for
manual range setting) and the A-H symbol is displayed. After the
first push of the SET/R key the A-H symbol is set and will stop blin-
king. The R-H-symbol continues flashing to be able to set the
manual measuring range with buttons UP and DOWN. If the SET/R-
key is pressed again, the R-H symbol is fixed. You can commence
measurement. Another (third) push of the SET/R key discards the
function and the previous normal mode is restored.
• In the function modes REL, MEM, RCL and CMP, push SET/R button
several times to return to normal mode.
Another possibility to exit from these modes is either to press the
button FUNC, DC/AC or ON/OFF once or to move the rotary function
switch to an adjacent position (observe all safety rules!).
d) DC Ohm/AC ( )
Press this button to toggle between DC and AC when the rotary fun-
ction switch is set to resistance measurement, continuity check, to vol-
tage or current or to switch from resistance measurement to acoustic
continuity check.
e) UP/DOWN
Press UP or Down button to determine the reference value in the fun-
ction modes REL or CMP or to address the stored value in the modes
MEM or RCL (reference numbers). In the function mode R-H (= Range
Hold) you can set manually the measuring range with these buttons.
f) Back Light
To switch on/off the back light (the back light is LED operated to save
energy) push the yellow button. After 15 s the back light will auto-
matically extinguish.
4.4.3 Terminal and Switch Imprint
a) Transistor Socket hfe
The eight pole transistor terminal is lettered symmetrically with (E)
Emitter, (B) Base, (C) Collector. Insert the transistor pins into the tran-

15
f) COM = Common Input Terminal
For all measurements, except capacity, temperature and transistor
measurement, the Black test-lead must be connected. (common-ter-
minal means minus or “-“ or earthing jack)
g) V/Ohm-Socket
For measurement of voltage, frequency, resistance, continuity, diodes
and logic tests plug in the Red test-lead in this terminal.
h) For power measurement insert in all sockets the measuring adapter.
4.4.4 Display Explanation and Symbols
a) Digital Display
Digital readings are displayed the main- and the sub-displays (small
displays) on a 4000-count basis (“3999“) with automatic polarity indic-
tion (-) (for negative voltage or reversed polarity). There are three
decimal point positions.
b) Analogous Bargraph
The bargraph consists of 43 segments and is faster than the digital
display. It functions as the needle of an analogous measuring instru-
ment, but without its mechanical disadvantages. Is is especially for
quick changing measuring signals, for which the digital display is too
“slow“. So you can quickly see tendencies in the measuring values.
If the measuring range is exceeded “OL“ for Overload is displayed the
bargraph is flashing and a warning sound is emitted (no acoustic sig-
nal during measurement of resistance, diode, temperature - “OL“
without thermo-element).
c) Data-Hold “D-H“
In this mode you can freeze a reading in the second (“small“) display
by pressing the SET/R button.
d) Range Hold “R-H“
In this function you can switch off the automatic range selection
(Auto Range) and set the measuring range manually. Each time the
UP or DOWN button is pressed the decimal point is moved one posi-
tion to the left or to the right, the units of measure are changed res-
pectively (e.g. from kHz to MHz during frequency measurement). To
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LOGIC = Logic Test - no function mode possible
/Ohm = acoustic continuity test - no Auto-Range during continuity
test, in the resistance measuring range Auto-Range and
manual range selction (R-H) is possible
= diode test - no R-H possible
CAP = capacitance measurement, A-R and R-H is possible
hFE = transistor test - no R-H possible
TEMP = temperature measurement in °C - no R-H possible
4 mA = DC and AC current measurement to max. 4 mA - A-R and R-
H possible
400 mA = DC and AC current measurement to max. 400 mA - A-R and
R-H possible
20 A = DC and AC current measurement to max. 20 A - A-R and
R-H possible
POWER = power measurement in [W] = Watt = unit for real power
d) 20-A-Input Socket
For DC- and AC-current measurements to max. ! 20 A. Insert the Red
test-lead into the input socket.
Attention !
During current measurement the rotary function switch must not be set
to voltage measurement (mV or V or other positions than 4 mA, 400 mA,
20 A).
e) mA-Measuring Socket
For measurements to 400 mA max.!, connect the Red test-lead, pay
attention that the rotary function switch is set to position “4 mA“ or
“400 mA“.

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display will show the difference in %, the middle sub-display will
show the offset and the right sub-display the preset reference.
g) MEM (= Memory)
Up to 10 measurements (reference number 0 to 9) can be stored and
recalled.
Proceed as follows:
1. Push function button until MEM flashes in the display, afterwards
press the key SET/R once. MEM is fixed and the reference number
flashes. Make your measurements and push the SET/R key once to
store the present measurement value in the first free memory loca-
tion = reference no. 0.
2. Press UP/DOWN button to go to the next free memory location
(reference no. between 0 and 9).
Make again your measurement and push the key SET/R once. The
selected memory now is addressed. If a memory no. which has been
used before is selcted the previous value is updated and stored with
the new measurement value. The memorized value appears on the
middle sub-display. To exit this function mode turn the function
switch (observe the safety rules!) or press the buttons FUNC or SET/R.
Hint!
If you exit the function mode because you pushed the SET/R button too
often, this function mode is left but the memory is not erased and can
be “recalled“ with the following function mode.
h) RCL (= Recall)
This function enables you to get the memorized reading back on the
LCD.
Follow these steps:
Push FUNC key until RCL flashes. Push SET/R once. RCL is fixed but the
reference number flashes. Press UP or DOWN buttons to address the
desired number where the measurement has been memorized. Press
SET/R button to get the memorized value back on the display. The
recalled value (ref. no. 0) will appear on the left sub-display, 2nd
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return from this function mode, press Set/Reset key twice (RESET) and
you will return to Auto Range.
e) Auto Hold A-H
In this function the meter will automatically record the minimum and
the maximum display reading, MIN and MAX values. These values are
currently updated = refreshed. The MIN-value is shown on the left
sub-display, the MAX-value on the right sub-display. On the middle
sub-display the average value = AVG is shown. This value is currently
“refreshed“. Press FUNC key until A-H flashes in this function mode.
Press once SET/R button. The symbol A-H is fixed, now the R-H (Range
Hold) symbol flashes. Now push the UP and DOWN key to select the
range for MIN, MAX and AVG measurement (e.g. for car voltage con-
trol the 40 V-DC range = decimal point in the middle). If you fixed the
range, press SET/R once again, the R-H sysmbol stops flashing. Both
symbols are visible in the top line of the display. You can start measu-
rement.
To exit this function mode press SET/R again or press FUNC or turn the
rotary function switch (observe the safety rules!), afterwards return to
normal settings.
f) REL (= Relative)
The relative mode enables the operator to compare the reference
value with a subsequent reading.
Proceed as follows:
• Set the function key at REL mode and press once the button SET/R
•Store the polarity by pressing the UP and DOWN keys, afterwards
press SET/R button.
•Press UP and DOWN buttons again to set the reference value you
desire and the decimal point (measuring range = R-H = Range-
Hold). Press UP / Down buttons and SET/R by turns to move to the
next digit.
• For final setting of the reference value press SET/R button once.
The meter will now display the difference between the stored refe-
rence value and the subsequent readings on the sub-displays, while
the present (true) measurement is on the main-display. The left sub-

19
acoustic or visual test (display of measurement) is possible. An acou-
stic signal is emitted at resistors below 40 Ohm.
c) Negative Polarity
Shows if test-leads are confused or indicates negative input with a “-“
before the measurement.
d) FREQ Frequency Measurement
You can measure frequency up to 40 MHz.
e) TEMP Temperature Measurement
You can measure temperatures from -40°C to +1200°C with a ther-
moelement (NiCrNi).
f) CAP Capacitance Measurement
The capacitance range lets you measure discharged capacitors of 4 nF
to 400 µF.
g) HFE Transistor Test
Enables you to measure the hFE value.
h) LOGIC Logictest
This function enables you to check and to display all usual logic levels.
i) Low Battery
A 9-Volt alkaline battery in this meter has an average life of approx.
20 to 30 hours. Low battery indication appears approx. 8 hours befo-
re battery is “dead“.
j) The following symbols indicate the units of the value displays:
AC = AC current or voltage
DC = DC current or voltage
mV = Millivolt (exp.-3)
V = Volts
mA = Milliampere (exp.-3)
A = Ampere
W = Watt
kWh = Kilowatt hours
Hz = Hertz
KHz = Kilohertz (exp.3)
MHz = Megahertz (exp.6)
+-
18
recalled value (ref. no. 1) on the middle sub-display and 3rd recalled
value (ref. no. 2) on the right sub-display.
i) CMP (= Comparison)
This function mode enables you to make the High/Low comparison of
subsequent readings, by comparing a reading with both the stored
high reference value and the stored low reference value.
On the sub-display “Lo“ appears for reading less than the low refe-
rence value, “Hi“ is displayed for reading more than the highest refe-
rence value and “Pass“ for a middle value between the low and the
high reference value.
To activate this function mode, push “Func“ until the symbol “CMP“
appears on the top of the display and “LOW“ flashes over the left
sub-display. Now push again SET/R button and then “UP“ and
“DOWN“ to set the minimum reference value with polarity. Press
after each change SET/R button again, to enter the setting and to go
to the next digit. As soon as the minimum reference (MIN) value has
been fixed, “HIGH“ flashes over the right sub-display. Set this high
reference value respectively (with polarity and four digit value). After
the reference values have been defined press SET/R key again. Now
“R-H“ for Range Hold flashes in the top line of the display. Set with
the UP and DOWN buttons the measuring range (e.g. voltage control
in a circuit under worst-case conditions). After the measuring range
has been entered (as far as a manual selection is possible) Comparison
= CMP is activated.
To exit CMP mode turn the rotary function switch (observe the safety
rules!) to an adjacent range or press “FUNC“.
Reset with the SET/R button is also possible, even during measurement.
4.4.5 Display Annunciators and Symbols for the Modes
a) Diode Test
The value displayed is the forward voltage at approx. 1 mA test cur-
rent. Range of 0 - 2.0 V.
b) Continuity Check
Enables you to check continuity of wiring, connections or fuses. Either

21
Each of the five voltage ranges presents an input impedance of 10 MOhm
(in parallel with < 100 pF). AC-voltage input is AC-coupled.
As soon as “ - “ is set before the display value during DC voltage measu-
rement, the voltage is negative (or the test leads are confused).
Hint!
During AC voltage measurement the right sub-display will show the dB-
value of the AC voltage, the middle sub-display the frequency and the
main display the present measuring value.
Due to the sensitive nature of the input terminal your meter might dis-
play any small values (not connected with the object). This residual value
will not affect the actual measurements. But Auto-Power-Off is not
active when the “phantom-measurements“ are displayed (for AC volta-
ge „mV“ and „V“).
During DC voltage measurement the three sub-displays below the main
display are active.
In the left sub-display the measuring value appears 1 second later, in the
middle sub-display the measuring value appears 2 seconds later and in
the right sub-display the measuring value appears 3 seconds later. This
means the left sub-display shows the measurement value which was 1 second
earlier on the main display, the middle sub-display shows the reading
which was 2 seconds earlier in the main display and the right sub-display
shows the value which was 3 seconds earlier on the main-display.
~V
Voltage Source Object
20
C= Centigrade Degree
F = Fahrenheit Degree
µF = Microfarad (exp.-6)
nF = Nanofarad (exp.-9)
KOhm = Kiloohm (exp.3)
MOhm = Megaohm (exp.6)
dB = Decibels
5. Measurement
5.1 Voltage Measurement
Attention!
Never exceed the maximum input limits. of max. 1000 VDC or 750 VACrms.
Do not touch circuits or parts of circuits, if you measure voltage more
than 25 VACrms or 35 VDC.
To measure DC or AC voltage proceed as follows
1. Set the rotary function switch to the desired position (mV or V)
2. Press DC Ohm/AC ( ) key, depending if you want to measure DC or
AC voltage. As soon as “AC“ appears in the display, you are in the AC
voltage range.
3. Connect the test-lead tips with the object to be measured (load, cir-
cuit etc).

23
designed for 250 V max.
Never measure currents exceeding 20 A. Only measure in circuits which
are fused with 16 A or in which powers exceeding 4000 VA could not
exist. Current measurements of 20 A may not last longer than 30 seconds
and may only be executed in intervals of 15 minutes.
Hint!
During AC current measurement the middle sub-display will show the
frequency of the AC voltage and the main display the present measure-
ment.
During DC current measurement the three sub-displays below the main-
display are active. In the left sub-display the present reading is taken 1
second later, the middle display the reading is taken 2 seconds later and
in the right display the reading appears 3 seconds later. This means the
left sub-display shows the measurement value which was 1 second ear-
lier on the main display, the middle sub-display shows the reading which
was 2 seconds earlier in the main display and the right sub-display shows
the value which was 3 seconds earlier in the main-display.
5.3 Continuity Test
With this function you can test dead leads, fuses, circuits.
Proceed as follows
Set the rotary function switch to /Ohm and press DC Ohm/AC button ,
until the symbol “ “ is displayed. Afterwards connect the test-lead tips
~
A
Current
Source Object
Multimeter
22
AC Voltage Measurement DC Voltage Measurement
5.2 Current Measurement
Follow these steps to measure DC or AC current:
1. Select with the rotary function switch the desired ampere position (4 mA
or 400 mA or 20 A).
2. Press DC Ohm/AC ( ) button, depending if you want to measure DC
or AC current. As soon as “AC“ appears in the display, you are in the
AC current range.
3. “Break“ the circuit to be measured and connect the test-leads in
series with the circuit or load. (See following drawing).
4. Switch on voltage at the object to be measured (circuit, load etc.) and
look at the display reading.
As soon as “ - “ appears before the value, the voltage is negative (or
the test leads are confused).
Attention!
Never measure currents in circuits in which voltages over 250 VDC/
VACrms could exist, this is life dangerous! Besides the fuses are only

25
5.4 Resistance Measurement
Attention!
Make sure all objects, circuits and components under test are without
voltage!
Set the rotary function switch to resistance measurement ( /Ohm ). If
the annunciator for continuity test “MΩ“ is displayed, press DC Ohm/
AC ( ) button until the symbol disappears.
Now connect the test-lead to the device you want to measure. Make sure
all power is removed. Auto Range always selects the appropriate range,
to avoid reading mistakes.
Normally the resistance of the test-leads can be disregarded (approx. 0.1
to 0.2 Ohm). But even this small value can cause inaccuracy in the 400 Ohm
range. To determine the error before measurement short the test-lead
tips together and read the resistance value in the display, this value must
be deducted from the display reading.
During resistance test, make sure that the contact between probes and
circuit is good. Make sure the test points are free of dirt, oil or solder flux
or similar, etc. This might seriously influence the measuring result.
If resistance over 4 MOhm is measured, the display might need a few
seconds to stabilize.
If the measured resistance value exceeds the range “OL“ appears in the
display or the line is interrupted/high-ohmic (> 40 MOhm)
Hint!
During resistance measurement the three sub-displays below the main-
display are active. In the left sub-display the present reading is taken
1 second later, the middle display the reading is taken 2 seconds later
and in the right display the reading appears 3 seconds later.
This means the left sub-display shows the measurement value which was
24
to the object to be measured. If the line resistance is less than 40 Ohm
a test buzzer sound is emitted.
Attention!
Never measure capacitors which carry voltage, as a possible discharge
could destroy your measuring unit.
Hint!
During continuity check the three sub-displays below the main-display
are active. In the left sub-display the present reading is taken 1 second
later, the middle display the reading is taken 2 seconds later and in the
right display the reading appears 3 seconds later. This means the left sub-
display shows the measurement value which was 1 second earlier on the
main display, the middle sub-display shows the reading which was 2 seconds
earlier in the main display and the right sub-display shows the value which
was 3 seconds earlier in the main-display.

27
•if the diode is o.k. the display will show “Good“
•if the diode is defective (short circuit) or low-ohmic “shrt“ (for short)
is displayed
•If the diode is defective in the sense of high-ohmic or the test leads
are confused (red to the cathode and black to the anode) “OPEn“ for
(open circuit) is displayed
5.6 Frequency Measurement
Attention!
Observe the max. input limits. Never connect voltages over 750 VDC/
VACrms (rms = eff).
It is life dangerous to touch the terminals or probe tips when measuring
voltages over 25 VAC or 35 VDC.
Disconnect the test-leads from the contact points when measuring vol-
tage (over 25 VAC or 35 VDC) before changing the meter function and
range. The sensitive electronic of the measuring unit might be destroy-
ed and you expose yourself to severe shock hazard.
Follow these steps to measure frequency:
1. Set the rotary function switch (10) to “FREQ“
2. Plug in the test-leads into the COM-socket (black = “-“) and the
V/Ohm-socket (red = “+“).
3. Connect the test-lead tips with the frequency source (generator, etc.).
Hint!
For most accurate measurements, we strongly recommend to use a BNC-
cable (Conrad Electronic offers adapter).
26
1 second earlier on the main display, the middle sub-display shows the
reading which was 2 seconds earlier in the main display and the right
sub-display shows the value which was 3 seconds earlier on the main-display.
5.5 Diode Test
Set the measuring function switch (10) to “ “. The annunciator for
diodes is displayed. Manual range selection is not possible.
Now connect the test-lead tips with the object under measurement an
off-circuit semiconductor line, the RED probe-tip to the anode, the
BLACK test-lead tip to the cathode (as a rule it is marked with a colou-
red ring, point etc.)
If you check a diode’s forward voltage, you will measure voltage of
approx. 0.25 V (Germanium) or 0.7 V (Silicium), if the diode is not defective.
If you reverse the probe-tips, this means Red to the cathode and Black to
the anode, you check the so called reverse direction.
If “OL“ is displayed the diode is open or above 2.0 V forward voltage.
However, if a value between 0 V and approx. 2.0 V is displayed, it shows
a forward drop voltage.
The test voltage of the diode test is enough to “illuminate“ most (low
current) LEDs. If the LED has an operating voltage of more than 2.0 V, the
DMM displays falsely that the LED is defective.
Attention!
During diode test, observe that the diode or the circuit in which it is
built in, must be without voltage. All existing capacities must be
discharged.
Hint!
During diode test the middle sub-display is active:

29
Follow these steps to measure capacitance:
1. Discharge each capacitor before testing. Never attempt to measure
the capacitance of a charged capacitor, you might damage your
multimeter.
2. Set the rotary function switch (10) to “CAP“
3. Measurements are only possible with the connector in the unit.
For polarized capacitors (unipolar) be sure to observe the correct
polarity (“+“ and “-“).
Hint!
Give the unit time of about 2-3 seconds to stabilizer.
During capacitance measurement the three sub-displays below the main-
display are active.
In the left sub-display the present reading is taken 1 second later, the
middle display the reading is taken 2 seconds later and in the right dis-
play the reading appears 3 seconds later. This means the left sub-display
shows the measurement value which was 1 second earlier on the main
display, the middle sub-display shows the reading which was 2 seconds
earlier in the main display and the right sub-display shows the value which
was 3 seconds earlier in the main-display.
5.8 Transistor Test
Attention!
The transistor jack is not protected against overload. You will void war-
ranty and you can damage the meter if you build and use your own
external transistor socket and connect it with the measuring unit.
+
-
28
Hint!
During frequency measurement the right sub-display shows dB-value of
AC voltage, the middle sub- display the AC voltage “V“ and in the main
display the present input value (frequency).
5.7 Capacitance Measurement
Attention!
When shorting capacitors (discharge), high-energy discharge may take
place. Caution life danger! Do not touch the terminals if there are capa-
citors with voltages over 35 VDC or 25 VAC. Use special caution in
environments or rooms with adverse environmental conditions where
flammable gases, steams or dusts exist or may exist ==> explosion
hazard!
~
~
~

31
play the present reading is taken 1 second later, the middle display the
reading is taken 2 seconds later and in the right display the reading
appears 3 seconds later. This means the left sub-display shows the mea-
surement value which was 1 second earlier on the main display, the
middle sub-display shows the reading which was 2 seconds earlier in the
main display and the right sub-display shows the value which was 3 seconds
earlier in the main-display.
5.9 Temperature Measurement
Temperature is displayed on the main and the sub-display.
The main display will show the temperature in Centigrade, while the
middle sub-display will show the temperature in Fahrenheit. The tempe-
rature range is from -40°C to + 1200°C. Temperature measurement is
exclusivley executed with K-type temp probes.
For temperature measurement proceed as follows:
1. Select “TEMP“ with the rotary function switch.
2. Plug in the temp probe into TEMP/CAP socket, observe the correct
polarity (narrow and wide tongue). (Use both sockets before and
after the separation bar in the middle).
Attention!
Do not connect voltages. The unit can be destroyed.
30
To measure the hFE-parameter (of amplification) of a transistor follow
these steps:
1. Set the rotary function switch to hFE position.
2. Insert the transistor you want to measure into the appropriate transi-
stor socket.
Pay attention to the following points:
•observe the sequence of connection of the transistor (you will find
it in the transistor comparative table).
•Some Darlingtons or special (power) transistors contain internal
base-to-emitter resistance that could cause undependable measu-
ring results.
•The hFE-measuring value is no absolute measurement. It only indi-
cates if the transistor is operating or not. The true amplification of
a transistor depends on its operating current. This multimeter sup-
plies a base current up to 10 µA; the collector current is measured
to calculate the respective hFE-value.
•It is not possible to measure transistors which are connected in a cir-
cuit.
•It is not possible to measure the hFE-value of FETs or other unipolar
transistors.
•If a low power transistor (e.g. BD 242 etc.) has too large terminals
for the test socket, do not force it into the test socket, as it could be
damaged.
•The hFE-measurement is affected by temperature differences As
soon as you touch the transistor when you plug it in the socket and
warm it with you fingers the measuring result could be influenced.
If the hFE reading is not stable, take the transistor out and let it
come to room temperature.
Hint!
During hfe-paramenter measurement of small power transistors the
three sub-displays below the main-display are active. In the left sub-dis-

33
In the mode “LOGIC“ it is not possible to select function modes
with “FUNC“ button!
Attention!
The voltage input of logic test is limited to max. 39.99 V. Never exceed
the maximum input limits.
Hint!
During logic-level measurement, the right sub-display will show the pre-
sent DC voltage value and the middle sub-display displays the frequency.
5.12 Power Measurement
To check the power input of a consumer e.g. TV-set, stereo-set in stand-
by mode or iron or bulb etc. a power meter adapter is needed. Is consists
of a plug/socket on one side and the multi-plug for the meter connection
on the other end.
First connect the multi-plug with the multimeter.
Afterwards connect the load/consumer which has been switched off with
the earthing-contact socket of the adapter and finally connect the
earthing-contact plug of the adapter with an earthing-contact wall
socket. Always control the correct contact of all plug connections and
the correct polarity of the multi-plug at the multimeter. The multi-plug
is lettered with the current path “20 A“ on the left, in the middle with
the gounding “COM“ and on the right with the voltage path “V/Ohm“.
Connect the multi-plug according to its lettering with the multimeter.
“20 A“ with the 20 A-socket, “COM“ with the COM-socket and “V/Ohm“
with the V/Ohm socket.
Attention!
If the connection with the multimeter is wrong or faulty, the meter, the
adapter or the consumer could be destroyed. Attention! Life Danger!
32
5.10 Usage of the Analogous Bargraph
The bargraph is easy to use and to understand. Is is comparable with the
needle of an analogous measuring instrument, but without its mechani-
cal disadvantages. Is is especially for quick changing measuring signals,
for which the digital display is too “slow“. So you can quickly recognize
see tendencies in the measuring values. If the range is exceeded the com-
plete bargraph scale with an arrow on the right flashes in the display.
Some functions are accompanied by an acoustic signal (mV-measure-
ment).
5.11 Logic Test
This measuring function lets you easily check logic levels in digital cir-
cuits.
1. Switch on your measuring unit.
2. Set the rotary switch (10) to “LOGIC“. This function displays “rdy“
(=ready).
3. Connect the test-leads with the COM-input socket (black lead) and
the V-Ohm socket (red lead).
4. Now connect the other end of the black test-lead to the “ground“
point of the digital circuit = “-“ (normally) and the red test-probe to
the supplying voltage point (V+ or Vcc).
5. If all leads are connected, press once Set/Reset-button to save the
“High“-Level.
6. While keeping the black test-lead connected to the gound, “separa-
te“ the red test-probe from the supplying voltage point (V+). Now
move the red test-pobes to the points in question. The multimeter
will immediately display one of the three modes
•if the level exceeds 70 % of the stored supply voltage “Hi“ is dis-
played.
•if the level falls below 30 % of the stored supply voltage, “Lo“ is
displayed.
•if the level is between stored reference value = 31 % and 69 % of
the stored supply voltage (e.g. 5 V), “——“ is displayed.

35
5.13 CMOS Signal Output
The mulitmeter M-3860M is equipped with a kind of “Function
Generator“ which supplies ten preset frequencies with a voltage of max.
3.3 V. To “tap off“ the signal insert the enclosed signal adaptor into the
capacitor socket, observe the correct polarity. The other end of the
adaptor has two small alligator clips.
To change the multimeter into a signal generator and to select the out-
put frequency follow these steps:
1. Select “SIG OUT“ with the rotary function switch.
2. Connect the enclosed signal adaptor (on one end with alligator clips)
with the capacity measuring socket of the multimeter.
34
To measure the real power of Cos Phi, to programme the price of KWh
and to measure KWh follow these steps:
1. Connect the measuring adapter to the meter as described before.
2. Set the rotary function switch to position “POWER“ and turn on the
unit.
3. Display in basic function mode: the mode digit on the left displays the
reference no. “0“.
The left sub-display shows the ampere reading “A“ (current), on the
middle sub-display AC voltage and on the right sub-display Cos Phi is
displayed (power factor). Cos phi is the power factor between
Ampere and Voltage, it is always “1“ if ohmic loads (consumers) are
concerned. For inductive consumers cos Phi is between 0.3 and 0.98.
The main display will show the true watts of your consumer.
4. In the second function mode, push “UP“ button once, the reference
no. “1“ appears in mode digit on the left.
The left sub-display will show costs per 1 hour (setting is possible in
the next function mode reference no. 2). Read the KWh in the midd-
le sub-display and the accumulated costs in the right sub-display.
5. In the third function mode, push “UP“ once more, the reference no.
“2“ appears in the mode digit on the left. The first digit of the left
sub-display is flashing. Enter with the buttons “SET/R“, “UP“ or
“DOWN“ the price for KWh, e.g. 0.23 DM.
This means the first digit remains “0“, therefore press SET/R. Then the
third digit is flashing, enter “2“ (= press 2 x UP) and confirm with
SET/R. Then the fourth digit is flashing, enter “3“ (= 3 x UP or 7 x
DOWN) and confirm with button SET/R. As the second digit is also „0“
press once again “SET/R“. The price per 1 KWh is now entered (middle
sub-display).
Attention!
After measurement has been finished, first pull the plug from mains
socket, before you disconnect the adapter from the measuring unit.
Attention! Life Danger!

37
5.14 Usage of the Mulitmeter in connection with a
Personal Computer
1. Installation
Follow these steps for installation and operation:
1.1 Install the software on your computer system.
1.2 Connect the interface cable with the measuring unit and the com-
puter (see figure).
Hint!
Switch off your measuring unit and your computer before connection.
1.3 Now turn on your multimeter and your computer.
2. Technical Information to write your own software.
The data format consists of a frame of 14 bytes. The frames are set as fol-
lows:
O 1O 20 30 4O W
36
3. Turn on the multimeter
4. In the basic function mode the reference number is displayed in the
left sub-display, the main display will show the respective frequency
“0.010 KHz“ (= 10 Hz). In the middle sub-display the external DC input
voltage is displayed in “V“ (max. 40 V).
5. To select other output frequencies push either “UP“ or “DOWN“ button.
For frequency and connected reference number see below:
0.010 KHZ = 10 Hz, reference no. 0
0.050 KHz = 50 Hz, reference no. 1
0.060 KHz = 60 Hz, reference no. 2
0.100 KHz = 100 Hz, reference no. 3
0.400 KHz = 400 Hz, reference no. 4
1.010 KHz = 1010 Hz, reference no. 5
2.021 KHz = 2021 Hz, reference no. 6
4.042 KHz = 4042 Hz, reference no. 7
8.084 KHz = 8084 Hz, reference no. 8
10.24 KHz = 10240 Hz, reference no. 9
Hint!
In mode signal output, the function modes and auto-power-off do not
work.
Attention!
Never short the output of the signal generator, as the output terminal
and the meter could be destroyed.

39
Attention!
Do not use abrasive detergents, gasoline, alcohol or similar. These
chemicals could damage the surface of the measuring unit. Besides sol-
vent fumes are dangerous to your health and explosive.
7. Technical Data and Accuracy
7.1 Technical Data
Display . . . . . . . . . . . . . . . . . . . : 3 3/4-digit liquid cystal display (LCD),
maximum reading 4000 with automa-
tic polarity display
Max. Measuring Rate . . . . . . . . : 2.5 measurements per second
Max. Input Current DC/AC . . . . : 20 A
Operating Temperature . . . . . . : 0 to +40 °C, relative humidity: < 75%,
not wetting
Storage Temperature . . . . . . . . : -10°C to +50 °C, relative humidity:
< 75%, not wetting
Temperature Coefficient
for Guaranteed Accuracy . . . . . : +23 °C ± 5 K (= Kelvin)
Battery Type . . . . . . . . . . . . . . . : NEDA 1604 9 V or 6F22 9 V, alkaline
Weight . . . . . . . . . . . . . . . . . . . : 305 g ± 10 g (with 9 V battery)
Dimensions (L x W x H) . . . . . . : 187 x 84 x 34 mm (without test-leads
and adaptor)
7.2 Accuracy
Accuracies are ± (% of reading = rdg + number of digit(s) = dgt(s)).
Accuracy is specified at 23 °C ± 5 K with a relative humidity of below
75 % not wetting for a period of 1 year after production. Warm-up time
is 1 minute.
38
BYTE 1 2 3 4 5 6 7 8 9 A B C D E
Example 1) DC - 3. 9 9 9 V CR
Example 2) 3. 9 9 9 MOh m CR
The sequence of data transmission from the meter:
Main-display kleft sub-display k middle sub-display kright sub-display
kmain-display ketc.
The following program is an example of a BASIC program that gets
single reading from the meter:
OPEN “COM1 : 9600,N,7,2,RS,CS,DS,CD” FOR RANDOM AS #2
PRINT #2, ”D“
IN$ = INPUT$ (4 * 14, #2)
PRINT IN$
CLOSE #2
END
Communication Specifications for Data-Transfer
Transfer Rate: 9600 Baud
Character Code: 7-bit ASCII
Parity: None
Stop Bits: 2
6. Maintenance and Calibration
Calibrate the meter once a year to maintain its accuracy over a longer
period of time.
Fuse replacement is described in point 2. (Safety Rules).
Battery replacement is described in point 4.1.
Clean the unit and the display with a soft, dry, antistatic cloth.

41
Mode Measuring Range Accuracy Resolution
AC 400 mA +/-(1.5%+3dgts) 100 µA
Current 40 Hz - 1 kHz 0.1 µA
400 mA +/-(2.5%+3dgts)
1 kHz - 10 kHz 0.1 µA
4 A +/-(2.0%+5dgts) 1 mA
4 Hz - 10 kHz
20 A ———”——— 10 mA
40 Hz - 10 kHz
valid at a frequency of 40 Hz to 10 KHz
Resistance 400 Ohm +/-(0.5%+1dgt) 0.1 Ohm
4 KOhm ———”——— 1 Ohm
40 KOhm ———”——— 10 Ohm
400 KOhm ———”——— 100 Ohm
4 MOhm ———”——— 1 KOhm
40 MOhm +/-(1%+2dgts) 10 KOhm
Continuity 400 Ohm +/-(0.5%+1dgt) 0.1 Ohm
Check buzzer sound for resistance < 40 Ohm
Capacitance 4 nF +/-(2.0%+3dgts) 1 pF
40 nF ———”——— 10 pF
400 nF ———”——— 100 pF
4 µF +/-(3.0%+5dgts) 1 nF
40 µF ———”——— 10 nF
400 µF ———”——— 100 nF
Diode Test range 0 to 2000 mV 1 mV
test current 1.5 mA max. at 1 KOhm
forward voltage max. 2.0 V
40
Mode Measuring Range Accuracy Resolution
DC 400 mV +/-(0.3%+1dgt) 100 µV
Voltage 4 V ———”——— 1 mV
40 V ———”——— 10 mV
400 V ———”——— 100 mV
1000 V +/-(0.5%+1dgt) 1 V
AC 400 mV +/-(0.8%+3dgts) 100 µV
Voltage 4 V ———”——— 1 mV
40 V ———”——— 10 mV
400 V ———”——— 100 mV
750 V +/-(0.8%+3dgts) 1 V
valid at a frequency of 40 Hz to 10 KHz
DC 400 µA +/-(1.0%+1dgt) 0.1 µA
Current 4 mA ———”——— 1 µA
40 mA +/-(0.8%+1dgt) 10 µA
400 mA ———”——— 100 µA
4 A +/-(1.5%+5dgts) 1 mA
20 A ———”——— 10 mA
AC 400 µA +/-(1.5%+3dgts)
Current 40 Hz - 1 kHz 0.1 µA
400 µA +/-(2.5%+3dgts)
1 kHz - 10 kHz 0.1 µA
4 mA +/-(1.5%+3dgts)
40 Hz - 1 kHz 1 µA
4 mA +/-(2.5%+3dgts)
1 kHz - 10 kHz 1 µA
40 mA +/-(1.5%+3dgts)
40 Hz - 1 kHz 10 µA
40 mA +/-(2.5%+3dgts)
1 kHz - 10 kHz 10 µA