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Homework HELP!

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yleets

New Member
an array of 20 LEDs ( 5 rows with 4 LEDs on each rows). The LEDs are identical and each row is powered by a DC voltage source of 14 volts. Each row has a 47Ω current limiting resistor. It is known that each resistor has power dissipation of 18.8 mW in this circuit. Determine:
(1) The current going through each resistor. [ans. 20 mA)
(2) The voltage across each LED
(3) The power dissipation over each LED
(4) The total current from the source
(5) The total power from the source (1.4W)
Note that Ohm’s law is not valid for the LEDs.

Can anyone help me please. i seriously dont get it
 

MikeMl

Well-Known Member
Most Helpful Member
There is a Homework Forum.

Hint, the key to your solution is that you are given enough info to determine the voltage drop across the resistor, which determines the voltage drop across four LEDs.
 
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