well you definetly need a series resistor....
dont think i know circuits where you don't need a current limmiting resistor.....
i am sure you need one. maybe a schematic could do?
The only flashing LED I know of (i.e., running without an external circuit) is a 2.2 volt model with a peak of 4 volts. If you connect this to a 9 volt battery without a limiting resistor, it will flash only once.
yes, the flasher is in the led, so the limiting resistors and all you need.
and ill say it one more thing...how often don't we use a limiting resistor?
If the duty cycle of the flaher is low, you can also do without the limiting resistor. But this is not at all a good idea. You should always use one to ensure long life of LED.
Hi Guys..
Just thought I'd chuck my two penneth worth in..
The flashing LEDs I have (the only ones I can get) are happy with 3.5v to 13v. NO RESISTOR.
The internal circuitry contains both the flasher and a current limiter circuit so the resistor is not required up to 13v.