Velleman DCA55 - Manual (Page 7)

Atlas DCA User Guide October 2007 – Rev 7
Page 7
Diodes
The Atlas DCA will analyse almost any type of
diode. Any pair of the three test clips can be
connected to the diode, any way round. If the
unit detects a single diode, the following
message will be displayed:
Pressing the scroll-off
button will then display the pinout for
the diode. In this example, the Anode of
the diode is connected to the Red test
clip and the Cathode is connected to the
Green test clip, additionally, the Blue
test clip is unconnected. The forward
voltage drop is then displayed, this gives
an indication of the diode technology. In
this example, it is likely that the diode is
a silicon diode. A germanium or
Schottky diode may yield a forward
voltage of about 0.25V. The current at
which the diode was tested is also
displayed.
Note that the Atlas DCA will detect only one diode even if two diodes
are connected in series when the third test clip is not connected to the
junction between the diodes. The forward voltage drop displayed
however will be the voltage across the whole series combination.
The Atlas DCA will determine that the diode(s) under test is an LED
if the measured forward voltage drop exceeds 1.50V. Please refer to
the section on LED analysis for more information.
Diode or diode
junction(s)
RED GREEN BLUE
Anod Cath
Forward voltage
Vf=0.67V
Test current
If=4.62mA