synchronization problem with flashing leds

Hi all,

I just bought about 15 flashing leds, mounted them in parallel with a resistor and a 9V battery and I have a problem as they are not synchronized (one lights in green and another one in red, etc ...).

Can anyone advise me how to solve this problem ?

Thank you very much !

Well for starters, each led should have its own resistor, the circuit in each led will probably be off just a few micro seconds from the next, I dont know if they would ever blink in unison...

Blinking LEDs often have built in resistors, depends on the exact LED you have. As Mike said they will never blink perfectly in sync. They'll start that way, but due to temperature/voltage and manufacturing variations they'll de-sync over any length of time. Normal LEDs and an actual driving circuit would be required to make them all blink at the same time.

thx for the answer Mike 2545, i guess i wasted a lot of money for nothing :s :s :s
Are u sure there is no possiblity to get it work ??

thx Sceadwian ill try that one !