LED turn

[eplanet]

hello
thanks for all of the help to me. this time please guide me for a circuit.
i want turn on one LED very slowly(power LED) as matteral fact when i turn on key power led slowly light. please show me what can i do it.

 

[audioguru2]

Hi Eplanet,
You don't say the supply voltage and you don't say the max current for your LED. Most LEDs have a max current of 30mA but usually operate at 20mA to be bright. Some LEDs have a max current of 700mA.

I made a circuit with a capacitor that charges slowly from a resistor when power is applied. An opamp and transistor boost the current to drive the LED.

 

[LostViking]

If all you want is to slowly turn the LED on, a simple RC is all that you need. The extra parts are NOT needed. Assuming your circuit can supply at least 20mA. Are you talking about an indicator for something in your car? Plenty of current capacity already..

I see a lot of replies on this forum forgetting the basic rules of design; KISS.

 

[ante1]

Perhaps 20mA is not enough for a Power LED as requested here!

 

[LostViking]

I could be wrong, but I think he is talking about the power LED on a device. Not power LED's as in high power. I also believe that the LED is being turned on now. He just wants to make this happen slowly rather than all at once.

Could be wrong and it wouldn't be the first time.

Hey eplanet, can you supply the missing details?