How to Switch 5V pIn like other pins??

I wish to make my LED Brighter by Connecting direct to 5v+ i.e Vref or Vout but they can't be switched i guess?? How to resolve? (Please don't suggest using Transistor)

An LED connected to 5v is no brighter than an LED connected to an output pin, provided that the specs of the LED or the Arduino are not exceeded, with any given current limiting resistor of a safe value.

If you don't like transistors, there are relays. :slight_smile:

You are very confused about things.
Vout is not 5V, nether is Vref. (at least you can't draw current from the pin without damaging things)

Connecting an LED with no resistor directly to 5V will damage it and while it might burn brightly it will not burn very long.

All LEDs have a maximum current that you should not exceed. This is controlled either by a resistor or by a constant current supply. Exceeding the maximum current will make the LED fail sooner and it will dim after a short time.

(Please don't suggest using Transistor)

Please don't ask for nonsensical things.

The nominal maximum output current for an Arduino pin is 40 ma. Some LED's seem to be ok at higher currents, but you should always have a resistor in series to limit current to a known level (better learn Ohm's law). If you wanted more than 40 ma. fed into an LED, I don't see why you couldn't supply it with the outputs from two digital pins. And of course, you can ramp the brightness down from max with PWM, but I wouldn't even try to predict what would happen if you did this with two output pins attached in parallel.

jrdoner:
I don't see why you couldn't supply it with the outputs from two digital pins.

I'm pretty confident this is a bad idea.

If one wants to use a higher current LED then use a transistor or sort of electronic switch.

Grumpy_Mike:
You are very confused about things.
Vout is not 5V, nether is Vref. (at least you can't draw current from the pin without damaging things)

Connecting an LED with no resistor directly to 5V will damage it and while it might burn brightly it will not burn very long.

All LEDs have a maximum current that you should not exceed. This is controlled either by a resistor or by a constant current supply. Exceeding the maximum current will make the LED fail sooner and it will dim after a short time.
Please don't ask for nonsensical things.

Just wait until he discovers that "transistors" come in NPN, PNP, Metal, Plastic, Silicon, Germanium, GCS, Photosensitive, UJT, Darlington, IGBJT, GAsFET, MOSFET, Enhancement mode, depletion mode, matched pairs, complementary pairs, overpriced singles (i.e. red R retail store), arrays, etc.... (did I mis any?) :slight_smile:

Yes, there are some transistors that have built in base resistors but I don't know a name for those. :slight_smile:

The nominal maximum output current for an Arduino pin is 40 ma.

NO ! It is an ABSOLUT MAXIMUM RATING.

It does not care what that says Arduino what counts is what Atmel said !

Atmel said that the maximum value in continuous operation is 20 mA.

Look at the graph below: at 40 mA output only deliver only 4 V. It is similar in sink mode.
Caution the curve is not a straight → if the current is multiplied by 2, the voltage drop of a ratio greater than 2 because of the temperature rise in the output .
Courant_max_atmega328p.png
One more time, for the micro-controller, what matters is what Atmel said, not Arduino said.

Note: this suggests that the Rdson of output transistors is about 30 ohms.