Emos MD-420, Manual

Page: 5 / 72

5
Diode Test and Circuit Continuity Test
Range Description Note
The screen will show the
approximate voltage of the
diode in the direction of
the current flow
No load voltage: 2.1 V
Built-in buzzer indicates
that the voltage of the
circuit is lower than 30 Ω
No load voltage: 2.1 V
Overload protection: 300 V DC/AC rms
For circuit continuity testing: When resistance is between 30 Ω
and 100 Ω, the buzzer may but does not have to sound.
When resistance is higher than 100 Ω, the buzzer will not sound.
Voltage Measurement
1. To measure voltage, plug the head of the black (negative)
tipped measuring conductor into the “COM” socket and the
head of the red (positive) conductor into the “INPUT” socket.
2. Turn the circular switch to set the type of measured voltage
to or . Select measurement in automatic range (AUTO
appears on the screen) or press the RANGE button to set the
multimeter to the expected voltage range.
3. When using the manual setting on a circuit with unknown
voltage, always set the highest possible range.
If “OL” appears on the screen when measuring in a manually
set range, you must switch to a higher range.
4. Connect the measuring tips to the measured voltage source.
The screen will show the measured voltage value. If the volt-
age is direct and the measuring tip is on the positive pole, a
positive voltage value will be indicated. Otherwise, a minus
sign will appear on the screen.
Note:
1. When the voltage range is low, the voltage value on the screen
may be unstable. In that case, the measuring tips were not
connected to a voltage source. This is a normal phenomenon
and does not affect measurement.
2. Never use the multimeter to measure voltages outside the 300 V
DC or 300 V AC range.
Immediately stop measuring if you exceed the 300 V range.
Otherwise, the multimeter may become damaged and you may
suffer injury by electric current.
Current Measurement
1. To measure current, plug the head of the black (negative)
tipped measuring conductor into the “COM” socket and the
head of the red (positive) conductor into the “INPUT” socket
(for currents lower than 200 mA). If the measured current is
in the 200 mA to 10 A range, connect the red measuring
conductor to the “10 A” socket instead.
2. Turn the circular switch to set the measured current to
µA , mA or A .
3. When using the manual setting with an unknown current
value, always set the highest range, then gradually reduce it
until the corresponding current value is shown.
If “OL” appears on the screen, you must switch to a higher
range.
4. Use the FUNC button to switch between measuring direct
or alternating current.
5. Select measurement in automatic range (AUTO appears on
the screen) or press the RANGE button to set the multimeter
to the expected current range.
6. Connect the tipped measuring conductors serially to the
measured current in the circuit.
The screen will show the measured current value. If the cur-
rent is direct and the measuring tip is on the positive pole, a
positive current value will be indicated. Otherwise, a minus
sign will appear on the screen.
Never use the device to measure current in circuits where
the idle open-circuit voltage is higher than 300 V.
Measuring current at higher idle voltage may cause damage
to the device (fuse burnout, electric discharge) or injury by
electric current!
Always make sure you are using the correct measuring range
before you measure!
Current Measurement
(Measuring Clamp DM634
– Optional Accessory to MD-420)
To measure direct current, you must use a DC measuring clamp.
To measure alternating current, you must use an AC measur-
ing clamp.
1. Plug the head of the black (negative) tipped measuring
conductor into the “COM” socket and the head of the red
(positive) conductor into the “INPUT” socket.
2. Switch to the range.
3. Use the FUNC button to switch between measuring direct
or alternating current.
4. Select measurement in automatic range (AUTO appears on
the screen) or use the RANGE button to set the multimeter
to the expected current range.
5. When using the manual setting with an unknown current
value, always set the highest range, then gradually reduce it
until the corresponding current value is shown.
If “OL” appears on the screen, you must switch to a higher
range!
6. Measurement is done by clamping the measured conductor
in the centre of the clamp.
You may only measure one conductor at a time.
The screen will show the measured current value. If the cur-
rent is direct and the measuring tip is on the positive pole, a
positive current value will be indicated. Otherwise, a minus
sign appears on the screen.
Note: Unifying deviation when measuring sensitivity
1. The sensitivity of measurement using the clamp is 0.1 A/0.1 mV.
If you are using a clamp with corresponding sensitivity, the
stated value is identical to the measured value.
2. When using a clamp which does not have a sensitivity of
0.1 A/0.1 mV, the values should be multiplied by a value based
on the clamp used so that the stated value corresponds to the
measured value.
Do not touch the measured circuit by hand or any other
body part.
Resistance Measurement
1. To measure resistance, plug the head of the black (negative)
tipped measuring conductor into the “COM” socket and the
head of the red (positive) conductor into the “INPUT” socket.
2. Switch to the Ω range for resistance measurement.
3. Choose automatic or manual measurement using the
RANGE button. If you are measuring in a range you set
manually and “OL” appears on the screen, you must switch
to a higher range.
4. Connect the measuring tips to the measured object (resis-
tor). The screen will show the measured resistance value.
Note:
1. When measuring resistances higher than 1 MΩ, it is necessary
to wait a few seconds before the measured value stabilises.
2. In an open circuit, the “OL” symbol will appear to indicate that
range has been exceeded.
Before measuring resistance, make sure the measured
object is disconnected from power supply and all capacitors
are fully discharged.