Review and Practice

Ohm's Law: Self check

In this activity you:

  • wrote scripts for all 3 versions of Ohm’s law and
  • manipulated Ohm’s law to solve for unknown quantities from known values.
  • Did your scripts perform accurate calculations?
  • Are you able to solve for any of the three variables in the Ohm's law equation when given the other two?

Questions

  1. What does this version of the Ohm’s law equations solve for?  V = I x R
  2. If you have measured voltage across a resistor and calculated its value based on its color code, what can you calculate with one of the versions of the Ohm’s law equations?  Which version?
  3. What unit is equivalent to V/Ω?
  4. If you only remember V = I x R, how can you figure out how to solve for R?

Exercises

  1. Given V = I x R, solve for I.
  2. The voltage across a 2 kΩ resistor in an LED circuit is 1.3 V.   Calculate the current through the circuit.
  3. The maximum current allowed through the circuit is 1 mA.  The voltage across a resistor in a circuit will never exceed 3.3 V.  Calculate the resistance value to allow maximum current without exceeding the specification.?

Project

Modify calculate_i_from_v_and_r.hex so that it displays the result in milliamps.