6
• Depending on the result, you can now adjust the measuring range by turning the switch (in
this case: direct current less than 20 mA).
• After completing the measuring process, remove the measuring cables from the object to be
measured and switch off the “EM393B” (rotary switch in “OFF” position).
Never measure currents in excess of 10 A in the 10 A range, as this can result in
damage to the “EM393B”. Also, never measure currents in excess of 200 mA in the mA
range, as this would trip the internal microfuse.
Alternating currents cannot be measured with the “EM393B”!
c) Resistance measurement „
Ω
“
Always make sure that all circuitry components, circuits and parts to be measured as
well as other objects to be measured are disconnected from the power supply and
discharged.
To measure the resistance “
Ω
”, proceed as follows:
• Switch on the “EM393B” by turning the switch to the largest measuring range (2000 k).
• Plug the measuring cables into the measuring sockets according to the colour coding.
• Check the measuring cables for continuity by connecting the two test prods to one another.
This must result in a resistance of about 0.5 ohm (inherent resistance of the measuring cables).
• Then connect both test prods to the object to be measured. Unless the object has a high
resistance or is discontinuous, the measured value appears on the display. Wait until the
display has stabilised.
• Depending on the result, you can now adjust the measuring range by turning the switch.
• After completing the measuring process, remove the measuring cables from the object to be
measured and switch off the “EM393B” (rotary switch in “OFF” position).
d) Diode test and continuity check
Always make sure that all circuitry components, circuits and parts to be measured as
well as other objects to be measured are disconnected from the power supply and
discharged.
• Switch on the “EM393B” by turning the switch to the diode symbol.
• Plug the measuring cables into the measuring sockets according to the colour coding.
• Check the measuring cables for continuity by connecting the two test prods to one another.
This must result in a value of about 0, and a humming tone must be audible. A measured value
of about < 50 ohm is recognized as representing continuity and a continuous tone is emitted.
• Connect both test prods to the object to be measured.
• After completing the measuring process, remove the measuring cables from the object to be
measured and switch off the “EM393B” (rotary switch in “OFF” position).
e) Test signal TTL
(Transistor-Transistor Logic):
Function check for transistor control (logic control in digital technology).
Output as 0 (no current) or 1 (current).
