The voltage drop across an LED is 2 Volts. It is connected to a 5 volt power supply with a resistor, as shown. What resistor value should be used to set the LED current to 4 mA?
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Answer:
Explanation:
The voltage drop across an LED is 2 Volts. It is connected to a 5 volt power supply
so voltage at resistor = 5-2 = 3V
by ohms' law, V=IR n current at 4mA or 0.004A
R = 3/0.004 = 750 ohms