Page 55 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Common Anode 7-segment Display
In this type of display, all the anode connections of the LED segments are connected together to logic 1. The
separate segments are lightened by applying of the logic 0 or LOW signal through a current limiting resistor to
the cathode of the particular segment a to g.
Therefore, common anode seven segment displays are very popular as many logic circuits can sink more current
than they can source. These displays are not a direct replacement in a circuit for a common anode display, as it
is the same as connecting the LEDs in reverse, and hence the light emission will not take place. Depending upon
the decimal number displayed, the particular set of LEDs is forward biased. For instance, to display the numeri-
cal number 0, we need to light up remaining segments corresponding to a, b, c, d, e and f. Then the digits from 0
through 9 can be displayed using a seven segment display.
Seven Segment Display Controlling Ways
There are different types of controlling techniques that are implemented by interfacing these seven segment dis-
plays with the external controlling devices. Seven segment displays must be controlled by other external devices.
Different types of microcontrollers are very useful to communicate with external devices like keypads, memory,
switches, etc. There are numerous interfacing techniques that have been developed to solve the complex problems
to communicate with displays.

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CITS : E & H - Electronics Mechanic - Lesson 9 - 29