Conrad VC333 Bedienungsanleitung Seite 9

2. Set the rotary switch to the required measurement range (200
Ohm, 2000 Ohm, 20 kOhm, 200 kOhm or 20 MOhm). Check the
test leads for continuity by connecting both test probes together.
3. Now connect the test probes with the object to be measured.
Notes!
When resistance measurements are performed, take care that
the measurement points which are to be touched with the test
probes are free from dirt, oil, solder flux or similar. Such condi-
tions can distort the measured value.
With resistances greater than approx. 1 MOhm it can be that
the display takes some time to stabilise. Should "1." appear in
the display, the measurement range has been exceeded or the
circuit being measured is open-circuit.
During resistance measurement, the three small displays to the
right near the main display are also active. In the upper small
display the presentmeasured value is indicated with a delay of
1 second, in the centre display the measured value is indicated
with a delay of 2 seconds and in the lower small display the
measured value is indicated with a delay of 3 seconds.
E Diode / continuity test
For the measurement of diodes or semiconductor paths, or to test
voltage-free conductors and cables for continuity, proceed as follo-
ws (observing without fail the following illustrations):
1. Connect the black test lead with the COM socket and the red
test lead with the V/Ohm socket.
2. Set the rotary switch to "->I-".
3. With diode test, the indicated value refers to the forward voltage
of a silicon or germanium semiconductor path (Si or Ge PN-junc-
tion). With continuity test, with resistances less than approx. 70
Ohm an acoustic signal sounds. This acoustic signal is also
heard with short-circuited (defective) diodes.
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red black
measuring measuring
Conducting direction
Now connect the test probes to the points to be measured in an
unpowered semiconductor circuit, with the red probe to the anode
and the black probe to the cathode (usually this being indicated by
a coloured ring, spot or similar ).
If a diode path is tested in the conducting direction, you will mea-
sure a voltage of approx. 0.3 V (germanium) or 0.6 V (silicon) to 3 V
(i.e. 300/600 mV to 3000 mV) will be measured provided that the di-
ode path is not defective.
When the test probes are reversed, i.e. red to the cathode and
black to the anode, then the non-conducting direction of the diode
path is checked.
If "1." (normally meaning overload) is displayed, the diode path is
not defective. If on the contrary a voltage value is displayed, then
either the object to be measured is incorrectly connected or is de-
fective.
During diode testing, make sure that the diode and
any circuit into which it may possibly be built, is ab-
solutely voltage-free. All capacitors present must
be discharged.
F Transistor test
The transistor connector is not protected against
overload.
black
red
measurin measuring
Blocking direction
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