WR Home      Topic Home      Chapter:  1  2  3 
<Previous Next>

Chapter 03

Circuitry for the Propeller PCB

Page 9

THE RGB LED



Now consider 15 such LEDs, named as LED_00 to LED_14
Note that how 18 wires can be used to switch on LEDs
15 individual Anodes of LEDs
1 Common Cathode for all 15 RED LEDs
1 Common Cathode for all 15 GREEN LEDs
1 Common Cathode for all 15 BLUE LEDs



18 Wires


Question 1: I want to switch on LED 1 ONLY and that too in RED colour, How to do it?
Ans: An LED needs both + & - to glow. Supply it and it will glow. To the common RED_Cathode give Ground Level Voltage (ZERO) and to the Anode of LED_01 Give a Logic 1 (HIGH) and it will glow RED.

Question 2: Now, I want to switch on LED 1 ONLY and that too in BLUE colour, How to do it?
Ans: An LED needs both + & - to glow. Supply it and it will glow. To the common BLUE_Cathode give Ground Level Voltage (ZERO) and to the Anode of LED_01 Give a Logic 1 (HIGH) and it will glow BLUE.

Question 3: What if I give ZERO to RED_Cathode & BLUE_Cathode both and the give logic 1 to LED_01?
Ans: You will see a resultant MAGENTA coloured light. As Blue and Red both LEDs glows nearby in the same 3-in-1 LED

Question 4: Which colours can be easily composed?
Ans: Seven Colours can be easily composed.





WR Home      Topic Home      Chapter:  1  2  3 
<Previous Next>