third drawing, 5v less the 3 volts accross the diode = 2v accross the 250R res, by ohms law = 8 Ma each LED
Also since each Atmega8 pin can source 40ma,
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
LED has 3V Fwd voltage Drop
1. In the following figure, what would be the forward voltage of the LED? (& why)
2. In the each of the following 3 figures
Assuming that the leds are not conducting. The voltage drop over the 2 leds is zero, which means there is current going through the resistor. which means the leds must be conducting.
Do you want to use 2 LEDs as they are in different locations, or was it to try and get more illumination ?
so zero current .
So this is how it works.
I will make it simpler for you: what is Vfwd when If = 0, for any led / diode of your choice?
he Vfwd is what the manufacturer states
Once again you are getting into nit picking pedantics
OK, even simpler than that.Here is the V-I curve for Osram LAE7F datasheet.Question: what is the Vf when If = 0?Quotehe Vfwd is what the manufacturer states What most people fail to comprehend is that Vfwd differs at different current levels. Vf = 3v @ 20ma has no meaning when If = 0ma.