New to electronics, need overall help, but mostly this, About LED's Help?

[amando96]

When turning on an LED How to make it go gradually on, and the gradually oFF?
i can make it go off gradually but not on...
is it anything like this?(the polarities might be wrong, i CBB to draw it well xD)
if it isnt, wich is most likely, How do i do it???

**broken link removed**

if the photo ist working, heres the link

**broken link removed**

btw that rectangle thing is a resistor ive been using 680 ohms...
thnx in advance

 

[rjvh]

When I see your picture you short the negative with the positive pole as you close the switch.

also both leads form the LED (one with resistor) are conected to the same point (same potential) so there's simply no current running through your LED in this set up

You dont give voltage potential so how do you come to the value of 680 Ohm

dimming a led can only be done by current control and that works the way up and down

conecting a LED is fairly simple: cathode (short lead on the LED) of the led you have to conect to the negative pole the anode (long lead on the LED) to the resistor and than to the positive pole of your power source

The resistor calculation is simple Ohms law

so you need to know what the exsesive voltage is (a led needs only 1.8V to 3.5V depending on the collor)

for example A red LED needs 1.8 V and you power source is 6 V

the resistor needs to "eat" 4.2 Volt

The current throug a LED can be from 8mA to 25mA (this is influencing the brightness)

so a bright set up will need 25mA 4.2V: 0.025A = 168 Ohm

a dim set up will need 8mA 4.2: 0.008A = 525 Ohm

Robert-Jan

 

[amando96]

When I see your picture you short the negative with the positive pole as you close the switch.

also both leads form the LED (one with resistor) are conected to the same point (same potential) so there's simply no current running through your LED in this set up

You dont give voltage potential so how do you come to the value of 680 Ohm

dimming a led can only be done by current control and that works the way up and down

conecting a LED is fairly simple: cathode (short lead on the LED) of the led you have to conect to the negative pole the anode (long lead on the LED) to the resistor and than to the positive pole of your power source

The resistor calculation is simple Ohms law

so you need to know what the exsesive voltage is (a led needs only 1.8V to 3.5V depending on the collor)

for example A red LED needs 1.8 V and you power source is 6 V

the resistor needs to "eat" 4.2 Volt

The current throug a LED can be from 8mA to 25mA (this is influencing the brightness)

so a bright set up will need 25mA 4.2V: 0.025A = 168 Ohm

a dim set up will need 8mA 4.2: 0.008A = 525 Ohm

Robert-Jan

go to the link again please, i think it's corrected, by the way, i have no idea why i put the LED's pins conected... My bad...

 

[rjvh]

your shematic doesn't mak sense

the LED is conected wrong and block all curent

the switch would short the capasitor if closed but this one can not have a charge as that the LED blocks that

and with the switch closed and the LED in the proper direction it would also not charge as that both pins are on the same potential

Robert-Jan

 

[bigkim100]

Oh Come On.....

I put into google was:"Fading LED" and I got so many fading circuits...I cant list them all. COME ON PEOPLE! dont be so lazy GOOGLE IT FIRST...THEN if you dont understand what you have found...THEN ASK.
This is a example of the height of lazyness!

YouTube - Fading LED with 555 time



**broken link removed**


Thats 3 out of about a hundred.
Oh, and your welcome...

 

[mramos1]

I can tell you in the current link, the LED is in backwards There have to be 100's of PWM/blink LED circuits out there on google.