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True [87]
3 years ago
12

A 12 vdc power supply powers a blue high intensity led with a forward voltage of 4.5 volts. The led is rated to withstand a maxi

mum current of 20 mA. What size resistor should be connected in series
Mathematics
1 answer:
dimulka [17.4K]3 years ago
6 0

Answer:

Resister of 0.15 W is to be added.

Step-by-step explanation:

In a given circuit we have the attachments

A power supply of 12 V

High intensity LED with forward voltage = 4.5V

LED is rated to withstand a maximum current of 20 mA or 20.10^{-30} A

We have to calculate the size of a resister to be connected in series.

Here we will apply the Ohm's law for the calculations

Total voltage of the circuit = voltage of LED + voltage across resistance.

12=4.5+20.10^{-3}.r

r = (12 - 4.5)/20.10^{-3}

r = 7.5×10^{3}/20 = 375 ohm

Therefore power of the resistance = i².r

P=i^{2}\times r

         =(20\times 10^{-3})^{2}\times 375

        = 0.15 W

Therefore a resister of 0.15 W is to be added.

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<span>Point H = (-6, 2)
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<span>It would be very helpful if you could take a pencil and a piece
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Notice that points H and J have the same x-coordinate, but
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