User manual

– it corresponds to the plus or supply line - depends on the measurements to be
performed and the socket labels. Our example instrument has three further
sockets installed. The right one is labelled "HzVO". Connect the red line to it,
e.g. to measure voltages (V) and impedances (Ω). "Hz" indicates frequency
measurements that are needed by specialists only. Usually, this socket is
selected for measurement of small currents as well, as they are usually found in
electronic circuits. Our instrument has its own socket intended for this. It is
labelled "µAmA". If usual currents in the area of electronics hobby construction
are to be measured, the red string is connected here. For multimeters with 3
connections, the low-current, voltage and resistor function are accessible
through a joint socket.
The fourth socket at the multimeter is labelled "20A MAX". It serves to measure
particularly high currents and is rather not needed by electrical engineers who
measure in circuits.
Details on the socket assignments and background for performance of measurements
can be taken from the multimeter manuals.
Figure 17: Most multimeters are equipped with 3–4 sockets to which the two
measuring strings are connected depending on measurement to be performed.
Figure 18: The black string is connected to COM. It corresponds to the return
line (the minus pole).
Figure 19: If voltage and
resistance measurements are to be performed,
this model requires the red
measuring line to be connected to the right socket
HzVO. To measure
small currents, it would have to be connected to the socket µAm A.
Correctly Setting the Meter
Multimeters do not simply measure voltages, currents and impedances. They must
be adjusted correctly. There are direct and alternating voltages and currents.
The multimeters also have several measuring areas and measuring ranges; for
example, the Voltcraft VC-11 alone has 5 direct voltage measuring ranges:
for very small voltages up to 200 Millivolt (mV), 2 V, 20 V, 200 V and 250 V.
Since it is often not possible to estimate precisely what voltage is expected in
a measurement, you should always set the highest measuring range. For direct
voltage measurements, this is 250 V in the Voltcraft VC-11. If the display only
shows a very low measured value like 14 V, you may switch down to the 20-V
measuring range. The device then measures highly accurately.
Processed in the same manner for all other measured values, i.e. alternating
voltages, direct and alternating currents, impedance measurements, etc.
Start with the highest measuring range to protect the sensitive measuring
electronics from overload and irreparable damage. Therefore, always start
measurement with the highest measuring range.
Figure 20: Observe selection of the right measuring unit (e.g. "direct current"
to ,measure direct currents).