Velleman DCA75 - Manual (Page 12)

Atlas DCA Pro User Guide December 2012 – Rev 1
Page 12
Bicolour LED (2 lead)
#1: LED
Red-K Blue-A
#1: LED
Red-K Blue-A
VF=1.823V at 5.00mA
Bicolour LEDs (2-lead types)
Bicolour LEDs are generally available in two main varieties;
2-lead and 3-lead types.
This section describes the testing of 2-lead
bicolour LEDs. These types are internally
connected in inverse parallel (back-to-back).
Similar to the diode network analysis, each LED within the
bicolour LED is detailed in turn.
This example shows that LED #1 has
its Cathode connected to the Red test
clip and its Anode connected to the
Blue test clip. The forward bias
characteristic is shown for LED#1,
1.823V at 5mA in this example.
Pressing scroll-off then shows the
details for the 2
nd
LED in the bicolour
LED package.
As expected for 2-lead bicolour LEDs,
we can see in this example that LED#2 has its connections in exactly the
opposite configuration to LED#1.
Note that it is common for the two LEDs within a bicolour LED to
have different forward voltage characteristics. Red is often the lowest
forward voltage, progressing through amber, yellow, green and then
blue (or white) with the highest forward voltage. See the table at the
bottom of the next page.
#2: LED
Red-A Blue-K
VF=1.944V at 5.00mA