You should be able to put 5 LEDs in series without any resistor at 9vsjaguar13 said:I'm not really good with electronics. It took me 7 months to figure out how to make the 10 LEDs blink. I have a 9 volt battery with one resistor total infront of 10 red LEDs. Are you saying to use more resistors or use do it in series? Should I put them in series, but go from resistor to LED to resistor to LED for all 10?
I would say so, it's certainly not good practice not to limit the current in some way.csaba911 said:
Yes, bearing in mind that your power supply needs to be high enough to power 10 LED's in series - at about 1.7V each you need 17V for the LED's, plus 3.3V across the 330 ohm (for 10mA through the LED's) - giving a total of 20.3V. At that you would only be wasting 33mW in the resistor, as you are going to flash them it will be less than that - 33mW when on, nothing when off (50/50 would give 16mW wasted). Identical LED's in series should all be the same brightness as they all get the same current.sjaguar13 said:So 10 LEDs of the exact same kind with one 330 resistor in series would make all of them the same brightness and use less of the battery?
Two would just about do it, but it would be close, and the LED's might well stop working as the batteries fade. Best solution is probably that posted above by Sebi - where you have three rows of LED's, you would simply have to choose the series resistor for the row of four to give the same current as the two rows of three.sjaguar13 said:So 1 9 volt battery won't be enough. I'd really need two 9 volt batteries?