Electronic – LEDs in Parallel, each with its own resistor

led

I am currently planning a project to light up a model of a cruise ship. I've done this before with some success.

To keep things simple I want to wire in Parallel. (Assuming I've understood the difference correctly; Each LED will have a direct connection to the power source)

I will be using a mix of colours; White, Warm White, Blue, Red, Green. Every LED is pre-wired or will be fitted with a resistor (470) to allow them to be run from a 12v source.

Every online simulation I run and my own previous experience says this will work perfectly fine, but every article I read seems to scream "no don't do it" and even then, opinions seem to differ.

enter image description here

Above is an example of my wiring diagram, forgive the crudity. There will be a lot more LEDs used than this, but this gives you an idea of my plans.

Any thoughts?

Thanks

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EDIT:

This is the overall schematic that I have planned:

enter image description here

Sadly I cannot provide the direct link for this circuit as it is too long for browsers apparently.

Best Answer

Your schematic is not ok, but your description is.

If you are using one LED and then the proper resistor the connection is fine. For instance (led values taken as example):

schematic

simulate this circuit – Schematic created using CircuitLab

Anyway, you will be wasting at least 3/4 of your power on the resistors.

My suggestion, whenever possible, put the maximum amount of leds in series:

schematic

simulate this circuit

Just keep in mind that

  1. you should not exceed 9-10V of drop on the leds (so for instance max number of 3V leds is 3)
  2. all the leds in the same line will sense the same current
  3. you will not be able to individually control the leds, just the lines (not a problem if you plan to turn them on
  4. for every branch, you will need to have at least one current-limiting device (a resistor is the cheapest option, but if you want higher quality control you can also use a constant current circuit made by two transistors and two resistors)

Note: as Olin said in the comments, many times you may want different currents for different LEDs. For instance, low brightness red LEDs may need a higher current than the standard blue ones, so it needs some balancing. So putting the leds in series should be the last step; please test the various currents before, in order to choose the appropriate value so that the effect is ok for you, then you can group them by current like shown before.

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