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# Lab 1 - Lighting an LED

last edited by 7 years, 5 months ago

Brad Haas, Thurs. 7-9 PM Lab

EE 47 Lab #1 – Lighting and LED

1. (a) Using Green LED lamp, must limit current to 25 mV

Input voltage from power supply = 5.02 V

V = IR

5.02V = 0.025A * R

R = 200.8 Ω

(b) This value is a minimum. If the resistance is any lower than this value, the current in the circuit will go up, meaning that the current in the circuit would be
greater than the
maximum current specified in the datasheet for the Green LED lamp.

(c) Using a digital ohmmeter, I measured the range of resistances to be 1.4 Ω to 10.1 kΩ for the potentiometer I used.

3. (a) No, the order of the components does not matter. As long as the switch is open, at whatever point it is at in the circuit will be open, meaning that the circuit

isn’t closed and electricity can’t flow.

4. (a) The battery provides a voltage of 1.5V to the circuit.

V = IR

9.0 V = 0.025A * R

R = 360 Ω

The video from this lab is uploaded here.