@ purple - he already explained he connected the digital out to his leds that have a max of 3 volts and both of them popped. There is no limitation of digital output amperes "current limiting circuit" , if it exceeds the 25 ma it can damage the PIC. Since we have limited specs here its probably best for him to validate the work with a meter to make sure it is best voltage for the led.

Sidenote though : I have used 5mm leds on the digital output with no problem but different components have different voltage compatibility range. His apparently are more sensitive. There are some leds meant for 1.5 to 2v range and those can pop if they get too much voltage.

Always use a resistor with an LED if the LED forward voltage isn't the same as the voltage output of the pin.

The V3 outputs +5v on the signal pins. So, if for instance your LED has a forward voltage of +3.0v and a forward current of 20mA you would require a 100ohm 1/8w resistor.

To make calculations for a single LED easier there are many online calculators out there, including this one.

i will have a look thanks

very helpfull indeed.i was thinking to using some 30 leds.

Categories -> Hardware -> How To Drive A Led Correctly From A Digital Output This post was on 3/27/2013. This post explains why you do not need a resistor. Thanks

where is this post to find.i can see only to 2014.

I thought the tutorial explained it pretty well.

"LEDs

LEDs come in all sorts of colors. The clear Blue, Red, Green and White LEDs make your project look great. You can connect an LED directly to the Digital Pin of your EZ-B. The Peripheral Extension cables make it very easy also!

The diagram below shows how to connect an LED to an EZ-B digital pin. The light can be controlled by using a Digital Control in ARC, or an EZ-Script command Set(). The one thing to notice is an LED connected to a digital port on the EZ-B does not need a resistor. This is because the digital ports on the EZ-B have pull-up resistors built-in."

I am buying some of these... 5V LEDS