Diode Test - VOLTCRAFT VC185 TRMS Bedienungsanleitung

e) Diode test
Make sure that all the circuit parts, switches and components and other objects of measurement are
disconnected from the voltage and discharged.
• Turn the digital multimeter on and select the measuring setting position
" " with the rotary switch (5). "M" and the " " unit symbol are
displayed in the LC display (4).
• Resistance measuring in auto-mode is selected by default and cannot
be switched off. The
measuring mode appear in the LC display (4). To select the diode
testing mode, press the SELECT button (1) three time until the diode
symbol " " appears in the LC display (4).
• Insert the red measuring lead into the V socket (8) and the black
measuring lead into the COM socket (9).
• Now connect the two measuring prods to the object to be measured
(diode, transistor, etc.). The red measuring tip indicates the positive
pole, the black measuring tip the negative pole.
• Connect the test leads with the prods to each end of the diode. Record
the measurement displayed. Reverse the test leads and record the
measurement displayed as well.
• Press the HOLD button (12) in order to lock a measured value if
needed. The hold symbol
HOLD button (12) in order to release the locked value. The hold symbol
disappears from the LC-display (4).
• If the LC display (4) shows a voltage in volt (V), the diode shows a forward bias. A voltage drop of 0.5 - 0.8 may
be observed on the pn-junction of a good silicone diode. If "OL" (in the centre of the LC display (4)) is shown, the
diode measured is reverse biased, or the diode is faulty (interruption).
• Perform a counter-pole measuring for verification. The red measuring lead corresponds to the positive pole
(anode), the black measuring lead to the negative pole (cathode).
• A silicone diode has an on-state voltage drop of approx. 0.5 – 0.8 V, germanium diodes typically have about
0.2 - 0.3 V.
• A diode is shortened if readings show the same voltage drop in both directions (approximately 0.4 V).
• A diode is bad (opened) when not allowing current to flow in either direction. The digital multimeter shows "OL" in
both directions in such case.
• After measuring, remove the measuring leads from the measuring object and turn the digital multimeter off. Turn
the rotary switch (5) to the position "OFF".
46
symbol and M for mega indicate resistance
appears in the LC-display (4). Press the
D