In the Arduino Uno's basic manual, connections for fading led are given. They have connected led on breadboard. The positive of led is connected through a resistor to the pin no 9 (pwm) and negative to the ground (ground of arduino with a wire). There is also a connection of 5V from arduino to breadboard. The led worked fine without that connection too. Is there any use to it? (It is given in the manual)
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1\$\begingroup\$ Probably not, but can you at least post a link for this manual and what page number you are referring to? or add a picture of the page. \$\endgroup\$– LinkyyyMar 19, 2019 at 14:35
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\$\begingroup\$ @Linkyyy added the picture, it is mentioned in the 2nd point, so it has no use! \$\endgroup\$– MeghMar 19, 2019 at 14:42
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2\$\begingroup\$ @Megh: No that 5V connection has no use. Maybe they used it in the illustration because it is neccessary for the next assignment? \$\endgroup\$– LinkyyyMar 19, 2019 at 14:45
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3\$\begingroup\$ @Linkyyy Yes, probably for controlling led using pushbutton. Just saw. Thanks. \$\endgroup\$– MeghMar 19, 2019 at 14:49
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1\$\begingroup\$ Book uses a Fritzing cartoon as a sole source of circuit information. No schematic in the book. This isn't the first time I see this in books about RPi and Arduino. It does a disservice to beginners. \$\endgroup\$– Nick AlexeevMar 19, 2019 at 20:49
2 Answers
There is no need for the 5V pin to be connected to the breadboard, maybe this setup is part of a tutorial and 5V will be used in a later part.
It serves no purpose. Pin 9 can provide enough current to power and dim a single led.