QM-7 SERIES SERVICE MANUAL
PAGE 1.2
JANUARY 2012
SUNRISE MEDICAL
Section 1
AC -
ALTERNATING CURRENT - Use this when you want to test
something that has AC current running through it. Typically you'd
want to test the voltage of an inverter (for cold cathodes or neons),
or a similar device
DC-
DIRECT CURRENT. This is the type of electrical power
produced by a battery. With a battery connector, the black wire(s)
should be connected to the negative(-) terminal of the battery
and should be considered the common ground. The red wire(s)
should be connected to the po) terminal of the battery and
is considered the “hot” lead.
Voltage-
This means Voltage or Potential Difference. It will
measure the potential difference between the two probes. To
measure voltage, connect the positive probe to a port that is
marked “V” or Voltage. Note: “mV” means milli-volts = .001 Volt
Current-
Since current is measured in Amps and the readout
value is in amps, the symbol "A" is used. On this setting the unit
measures current that is
fl
owing through the part of the circuit
between the two probes (the meter itself). Typically, you need to
plug the positive terminal into a port marked “A” or Current. You
need to put the meter “In Series” in the circuit to use this feature
correctly.
Resistance-
This symbol represents Resistance and is measured
in Ohms. You can use this setting to measure the resistance
between two points; for example across a piece of wire or a
resistor (to check its value). If you don’t have a continuity check,
then this can be used to check for shorts. Any value below 0.05
Ohms constitutes a short, meaning that whatever the probes are
attached to is connected electrically.
Continuity-
A commonly used function. By putting a current
through the two terminals (the same as the Ohm-meter function)
it can be determined if the resulting value is within the “contact”
range, this is signi
fi
ed with a beep. Found on some multimeters,
it allows a check for shorts without taking your eyes off your work.
Other meters signify this with a small
fl
ashing light.
Multimeter Symbol Defi nition
