KEY FEATURES OF LED 7-SEGMENT 0.56″ RED CA:

• 7-Segment with common anode (CA)
• 0.56″ high characters
• 20 mA current
• 2V forward voltage drop
• Red color

7-Segment displays are very useful for making numeric or hexadecimal displays such as for a clock, timer, counter, voltmeter or similar application.

Theory of Operation:

These displays have 7 separate LEDs comprising the 7 segments of the display plus an 8th LED that functions as a decimal point.  The LEDs are labeled segment A thru G and the decimal point is DP.

The displays are common anode (CA) type which means that all 8 of the LEDs have their anodes tied together (in common) and these connect to the center pin on each end of the display which are then connected to Vcc.

To light a particular segment, the control (cathode) pin for that segment is driven LOW.  These 8 control pins should each have series current limiting resistors to prevent damage to the LED module or the uC.  Instead of the control pins, current limiting resistors can be put on the pins connected to Vcc so that fewer are needed, but in that case the brightness of the display will vary depending on how many segments are lit at one time so that practice is not really recommended.

The pin-out shown here is as if you are looking at the face of the display.