LED & Resistor Calculations

For problems 1-5, determine the required resistance and the standard resistance for each LED. Show your work. 1. 6V battery, green LED. R = (Vs - VL) / I, where R = required resistance, Vs = Voltage supplied (from battery), VL = voltage load of LEDs (see chart), I = 0.015 A (a typical current for LEDs). Standard Resistor values: 100, 220, 330, 470, 1000 ohms. Available battery voltages: 6V, 9V, 12V, 18V. What is the correct standard resistor value to use for the green LED in this configuration?

• 100 ohms

• 220 ohms

• 330 ohms

• 470 ohms

For a blue LED connected to a 9V battery, using the formula R = (Vs - VL)/I with I = 0.015 A (and assuming VL ~ 3V for a blue LED), determine the required resistance and select the closest standard resistor value from the list [100, 220, 330, 470, 1000] ohms.

• 327 ohms required; choose 330 ohm standard resistor

• 400 ohms required; choose 470 ohm standard resistor

• 600 ohms required; choose 1000 ohm standard resistor

• 450 ohms required; choose 470 ohm standard resistor

For problems 1-5, determine the required resistance and the standard resistance for each LED. Show your work. 3. 9V battery, white LED. R = (Vs - VL) / I, where R = required resistance, Vs = Voltage supplied (from battery), VL = voltage load of LEDs (see chart), I = 0.015 A (a typical current for LEDs). Standard Resistor values: 100, 220, 330, 470, 1000 ohms. Available battery voltages: 6V, 9V, 12V, 18V.

For problems 1-5, determine the required resistance and the standard resistance for each LED using the formula R = (Vs - VL) / I, where Vs is the battery voltage (9V for problem 4), VL is the voltage load (for red LEDs), and I = 0.015 A. For 2 red LEDs in series, choose the correct standard resistor value from the options below.

• 100 ohms

• 220 ohms

• 330 ohms

• 470 ohms

For a circuit with a 9V battery and 2 yellow LEDs (each with a voltage drop of approximately 2.1V), using the formula R = (Vs - VL) / I (with I = 0.015 A), what is the required resistance and which standard resistor value should be used?

• 320 ohm required; use 330 ohm

• 470 ohm required; use 470 ohm

• 100 ohm required; use 100 ohm

• 220 ohm required; use 220 ohm

For question 6, determine the supply voltage (Vs), the required resistance R, and the standard resistance for the red and white LEDs in series.

• Vs = 9V, R = 560Ω, Standard = 560Ω

• Vs = 12V, R = 470Ω, Standard = 470Ω

• Vs = 5V, R = 330Ω, Standard = 330Ω

• Vs = 15V, R = 680Ω, Standard = 680Ω

For question 7, determine the supply voltage (Vs), the required resistance R, and the standard resistance for the white, red, and blue LEDs in series.

• A) Vs (supply voltage), R (required resistance), and the standard resistor value for the series connection

• B) Only Vs

• C) Only the required resistance R

• D) Only the standard resistor value

For question 8, determine the supply voltage (Vs), the required resistance R, and the standard resistance for the red, red, yellow LEDs in series.

On the breadboard, a battery is connected to the positive and negative rails. Which of the following best completes the circuit configuration?

• A battery and three resistors in series

• A battery and three resistors in parallel

• A battery with three resistors in series and three resistors in parallel

• A battery with two resistors in series and one resistor in parallel