##PWM

PWM stand for Pulse Width Modulation, it is a trick to get analog like result with your digital pins, do do so it emit a square wave by altering low and high current each cycle is divided in 256 parts, here you are my precious 8bits !!! more about pwm here

####pwm waves

+----------------------------------------------------------------------------------+
| 0% cycle (0)                                                                     |
|----------------------------------------------------------------------------------|
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|                                                           5v                     |
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|                                                                                  |
|                                                                                  |
|+-------------------------------------------------------+  0v                     |
|                                                                                  |
+----------------------------------------------------------------------------------+
+----------------------------------------------------------------------------------+
| 25% cycle (64)                                                                   |
|----------------------------------------------------------------------------------|
|                                                                                  |
|+--+          +--+          +--+          +--+             5v                     |
||  |          |  |          |  |          |  |                                    |
||  |          |  |          |  |          |  |                                    |
||  |          |  |          |  |          |  |                                    |
||  |          |  |          |  |          |  |                                    |
||  |          |  |          |  |          |  |                                    |
||  |          |  |          |  |          |  |                                    |
|+  +----------+  +----------+  +----------+  +----------+  0v                     |
|                                                                                  |
+----------------------------------------------------------------------------------+
+----------------------------------------------------------------------------------+
| 50% cycle (127)                                                                  |
|----------------------------------------------------------------------------------|
|                                                                                  |
|+------+      +------+      +------+      +------+         5v                     |
||      |      |      |      |      |      |      |                                |
||      |      |      |      |      |      |      |                                |
||      |      |      |      |      |      |      |                                |
||      |      |      |      |      |      |      |                                |
||      |      |      |      |      |      |      |                                |
||      |      |      |      |      |      |      |                                |
|+      +------+      +------+      +------+      +------+  0v                     |
|                                                                                  |
+----------------------------------------------------------------------------------+
+----------------------------------------------------------------------------------+
| 75% cycle (191)                                                                  |
|----------------------------------------------------------------------------------|
|                                                                                  |
|+---------+   +---------+   +---------+   +---------+      5v                     |
||         |   |         |   |         |   |         |                             |
||         |   |         |   |         |   |         |                             |
||         |   |         |   |         |   |         |                             |
||         |   |         |   |         |   |         |                             |
||         |   |         |   |         |   |         |                             |
||         |   |         |   |         |   |         |                             |
|+         +---+         +---+         +---+         +---+  0v                     |
|                                                                                  |
+----------------------------------------------------------------------------------+
+----------------------------------------------------------------------------------+
| 100% cycle (255)                                                                 |
|----------------------------------------------------------------------------------|
|                                                                                  |
|                                                                                  |
|+-------------------------------------------------------+  5v                     |
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|                                                            0v                    |
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+----------------------------------------------------------------------------------+