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PostPosted: 10.02.2003 19:09 
Hi!
I was wondering what Voltage the LEDs is on.. So I'll choose the same which makes it unnessecary to recalculate the values =)


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PostPosted: 11.02.2003 01:17 
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Same as the supply is, in this case 5 volts.


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PostPosted: 25.03.2003 09:35 
But then what is the resistor on the down right corner doing there (the 220 ohm one)?


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PostPosted: 25.03.2003 09:46 
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I ment that the pins give 5 volts. Those leds are just regular red leds and need to have a proper current limiting resistor. Just get the leds you like and calculate the resistor.


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PostPosted: 10.04.2003 16:41 
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Mmm, the outputpins do not deliver 5V when there is a LED attached to it and powersupply is 5V.
So if you use a 3,3V blue LED, outputvoltage is about 3,4V, while the LED becomes 2,7V and the rest of the voltage is over the resistor.
The 4017 is limitting the current already, max Iout is about 3mA.


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PostPosted: 28.04.2004 06:31 
Actually, if you want to get technical the voltage coming out of the pins will be the same before the resistor (Unless the cirucit is broken) as it is after. It doesnt matter if the resistor is before or after the LED's the voltage going into the LED is going to be whatever the voltage is on the other side of the resistor, the current has to go through a complete loop, therefore no matter how much juice you are trying to pump into the circuit, only as much will go in as can come out, so your resistor is sorta your bottleneck so-to-speak.


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