Hello,

May I connect led each other by parallel connection? I tried it and it works but I need to clarify it.

Thank you so much.

 

You have already proved that you can. The question is "what happens if I connect LED's in parallel?".
When LED's are made each one has a little differeent characteristic. The current through the device causes photons to become emitted as the current crosses the band gap. So the brightness stays more constant across a wider temp range and voltage change if they are wired in series and see the same current. This is usually more of a problem when the LED's are an important part of your system presentation and looking consistant is an issue. But as you have already done, driving them in parallel can certainly be done.

 

If you look at a graph of current versus voltage for an LED (or any diode) you'll see that it becomes very steep once the component conducts--a small increase in voltage causes a big increase in current. That means that if you put LEDs in parallel (give them the same voltage) you might find that small variations between the parts would give you big differences in current. If you use similar parts from the same manufacturing batch, this might not be noticeable, but generally it's not a good idea. Wiring the LEDs in series is a better plan, if you can arrange them that way.

 

Each row of LEDs has its own resistor, You can have as many rows as you want.

LEDs, 555s, Flashers, and Light Chasers