eplanet Posted April 20, 2007 Report Share Posted April 20, 2007 hellothanks 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. Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 20, 2007 Report Share Posted April 20, 2007 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. Quote Link to comment Share on other sites More sharing options...
LostViking Posted May 22, 2007 Report Share Posted May 22, 2007 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. Quote Link to comment Share on other sites More sharing options...
ante Posted May 23, 2007 Report Share Posted May 23, 2007 Perhaps 20mA is not enough for a Power LED as requested here! Quote Link to comment Share on other sites More sharing options...
LostViking Posted May 24, 2007 Report Share Posted May 24, 2007 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? Quote Link to comment Share on other sites More sharing options...
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