Resistor placement between the LED and ground ?

Other Hardware General Electronics
1

As a beginner I am unclear on why the SpaceShip Interface exercise (page 33 of the Arduino Project book) calls for the resistors to be placed between the LED and ground vs. placing the resistor between the LED and power supply.
Does the resistor serve the same function in lowering the voltage to the LED when placed between the LED and ground?

Jack

2

As long as it is in series with the led you are OK.
The resistor limits led current to a desired/safe level.

Not everyone has your documentation, attach an image to your post.
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3

In series connections the order does not matter :slight_smile:

5

And of course limiting the current sets the voltage to the correct value as that's a property
of the LED for the current set...

More formally you solve some equations relating the supply voltage, the resistance and the
non-linear (exponential) response of the LED. In practice you don't bother.

6

Like LarryD said - You should include a link or image of what your question is about, because it allows people to better answer your question.
It took a while to find your "Arduino Project" book, but I think I found a schematic at Arduino Starter Kit Multi-language — Arduino Official Store.
The wiring of this particular circuit allows for the LEDs to be turned on by applying a HIGH (1) on the DIO pins. if the resistors were tied to 5V, and the LEDs reversed (very important!), you would have to apply a LOW (0) to the DIO pins to light the LEDs. But everyone else was right - the order of the LEDs and the resistors doesn't affect the LEDs.

See how including an example in you post will change the answer!?!

7

You may find the photos at #7, #8 and #9 on this thread useful.

8

Hi JimboZA
Nice to see you back.
I was looking at you IR remote document the other day.
.

9

LarryD:
Hi JimboZA Nice to see you back.

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10

Thanks... Took an Arduino sabbatical... on the other hand, I'm a radio ham ZS6JMB now along with my son ZS6HMB. You can see us both on APRS @ aprs.fi (Pity I can't afford any HF gear right now, but I'm at least on 2m through the local repeaters here in Johannesburg, handheld and mobile.)