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Class : Apprenti
Posts : 20
Registered on : 24/04/2008
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Hi guys,
I've tried using the LED assembly wizard on this site but I'm a little confused about one thing: it doesn't ask for the power supply's current, only its voltage. How does it know what resistors to use, and whether to put the circuit in series or parallel if it only has the power supply voltage, LED maximum voltage and LED maximum current?
My power supply for the circuit is 4V and 1000mA, but my LEDs can only take 100mA maximum, so I'm wondering how the LED assembly wizard will figure this out, or doesn't power supply current matter?
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Class : Apprenti
Posts : 23
Registered on : 14/11/2009
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Hi, the 1000mA is maximum current the source can provide at such voltage.
But the true current in circuit depends on voltage and resistance according to Ohms Law. That is I=U/R. For example 4V source gives 100mA current to circuit of total resistance of 40 Ohms.
But the using leds, you subtract its voltage before counting the resistor value.
Just add the other values to calculator, it will recommand you paralell circuit with resistors depending on preferred LED current (eg. preferred brightness).
Look at FAQ, there are recomanded values depending on IR modded/unmodded camera.
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