How to connect 2 or 3 LEDs to the battery?

I would like to point out right away that my knowledge in the field of electronics ends with the ability to turn on the light ...
I need to power two / three LEDs that are about 10-15 cm apart (a dollhouse for a baby girl) and I have no idea how to do it .. is it enough to connect these two rods coming from the diode with a 12V battery? All for 1 battery, does each diode have to have its own?

Please help...

LEDs need to limit the current consumption, resistors are most often used. You can connect in parallel, then you need to count each one and add a resistor or in series, then we add one common in series, to count them you need: supply voltage, diode voltage and diode current not exceeding the allowable.
Read this topic: Link .

and I can ask more pathologically? What is this resistor? Where to connect it and how ...? The same LEDs, white, as small as possible. I found something like this on the allegro
led-12v-3mm-real-12v-resistor-free

Moderated By ANUBIS:

3.1.18. Do not send links that will cease to be active after some time. This will make the discussion meaningless.

A resistor is a popular resistor. Often, when buying diodes, it is added for free. For example, for 12V a resistor of 510?-560? is added. To each diode, to one of its ends, it should be connected in series with the 12V power supply. We are talking about white LEDs, because color matters.
From what you wrote above, you can buy diodes with a built-in resistor for a voltage of 12V. We are talking about the given link. In such a system, you connect the diodes in parallel and connect them to 12V.

Regarding the parallel connection itself, the diodes have an anode and a cathode. You have to connect them in harmony, i.e. cathodes to cathodes and anodes to anodes. For ease of use, they have different cable lengths. In other words, the longer ends should be joined together and the shorter ones should be joined together.



You can find more about diode connections here: Link

What if these tips are too short? Ie. The diodes are to be separated by several cm ... or if so, what can I extend them?

Yes of course. You connect the cables you need. Some time ago I was lighting a nativity scene for someone for Christmas. I have cleverly hidden the cables.
Here you have an example of connecting three (typical) LEDs with matching resistors.



The connection in your case may look like below. Of course, resistors are not necessary with LEDs that have them.

And how many such diodes can I connect in this way? If I would buy duods without a built-in resistor, how do I find one that will be suitable? And then one at the beginning of the cable is enough, or must it be separate for each diode?

meduzaaa wrote:

I need to power two / three LEDs that are about 10-15 cm apart (a dollhouse for a baby girl) and I have no idea how to do it

The voltage of an ordinary diode is color dependent. White is 3.2V. Three diodes connected in series give 9.6V. Thus, one 9V battery is enough for 3 white LEDs connected in series. For two white LEDs connected in series, 4 AA batteries (4 x 1.5V connected in series together 6V) are sufficient. In this case, no resistors are needed.

However, the problem is age. Children shouldn't play with batteries to keep them from eating, or lest they puncture the batteries or anything like that. Better to buy another one with ready lighting and approval.

I will connect to the topic.
I have 4 Power Leds - 3W, voltage 3.4 - 3.6 mA.
I connect the 12-14 V voltage to the car battery

calculations show that I should use a 15 Ohm and 7.3 W resistor

question:
if I give a 15 OM 50 W resistor, can I connect 4 diodes to 1 resistor in parallel?
the power consumption will be about 30 W so that there will be a power reserve of the resistor so that it does not burn out.
will it work

lev-ele wrote:

I will connect to the topic.
I have 4 Power Leds - 3W, voltage 3.4 - 3.6 mA.
I connect the 12-14 V voltage to the car battery

calculations show that I should use a 15 Ohm and 7.3 W resistor

question:
if I give a 15 OM 50 W resistor, can I connect 4 diodes to 1 resistor in parallel?
the power consumption will be about 30 W so that there will be a power reserve of the resistor so that it does not burn out.
will it work

First. Pay attention to what you write. We don't have a cryptology department.
Second, we measure voltage in volts (V), not milliamps (mA).
3W LEDs come from several different manufacturers and in several different finishes. If you know your type, you can find their exact datasheet. There will be, among other things, the current range to drive them.
You didn't mention the one you took.

Third, if you connect 4 diodes to one resistor, the conditions will change. The currents of all LEDs add up, and a new calculation has to be made. It could be done, but not with a resistor calculated for one LED.

Resistors are not some very expensive equipment. It is recommended that each LED has its own so that in the event of damage, you do not lose all the LEDs, which, on the other hand, already cost a bit more. It is a pity, to save on an item worth a few zlotys, to lose a few items worth a dozen or several dozen zlotys.

Fourth: Don't plug into topics from many years ago. Create your topic.

the fact was a little confused in terms.
I know that when I connect them to one resistor in series, the conditions change, but I don't know how the conditions change when I connect them in parallel to one resistor.
I have a resistor more than 5 times stronger than 1 diode requires, so on 4 diodes it should be ok.
I don't know much about it, so I'm writing for it.
Please be understanding.

I have a diode like this:
https://allegro.pl/oferta/dioda-power-led-3w-ultrafioletowa-uv-430nm-45mil-7005206543

a resistor like this:
https://www.sklepledowy.pl/pl/p/Rezystor-50W-15ohm-dla-Zarowek-Led/833

The current of one diode is 700mA. When you connect four pieces in parallel, the current will be 4 x 0.7A, or 2.8A. For this current, you need to calculate the resistor. By the way, if each of them had its own resistor (lower in power and dimensions), it would be better. The point is that if one of them fails, the others will get more current and burn out too. You can also connect them in series, but then you need a higher voltage with a current of 0.7A.
Formula to calculate the resistor: R = (Usas - Udiody) / Idiody
It is best to measure the actual current in the circuit.

A much better solution is to use a driver.

Hello,

lev-ele wrote:

calculations show that I should use a 15 Ohm and 7.3 W resistor

Show these calculations. I recommend Ohm's Law, but you need to learn the basic concepts beforehand. It will be electricity, voltage, power. Connecting it in parallel does not make sense. Serial 4 or 3, or use the driver.

In order not to combine, because I'm not too strong in it, maybe someone will just tell me what resistor or just driver to buy for the diode> https://allegro.pl/oferta/dioda-power-led-3w-ultrafioletowa-uv-430nm-45mil -7005206543. Or maybe someone can make a driver for me.

I need to connect FOUR LEDs in different places so that it is best to connect in parallel.
powered by a 12-14 V motorcycle battery.

Here you have an example driver for 700mA. Link
It can power from one to three diodes connected in series from your battery. When using the driver, you don't have to worry whether the battery is 14, 13 or 12V. The driver monitors the 700mA current all the time. When you use a resistor, unfortunately the diodes will shine dimmer at lower voltage, when you select the resistor to, for example, 14V and the voltage drops to 12.5V.

Thank you so much for help