Circuits Day 2

April 21 and 22

Warm up1. Look over the notes from before break – if

you were absent, get the notes from someone. There will be a verbal quiz on the new equations.

2. Your notebook check will be 25% of your test grade

You have until I finish passing out papers to look over your notes

Equation Review

• What is Ohm’s Law?• How do we find the equivalent resistance of

resistors in series?• How do we find the equivalent resistance of

resistors in parallel?

• What are the three different equations for Power?

Ohm’s Law Practice

Complete number 18 of the Ohm’s Law worksheet from last class (hint: you don’t have to use every single battery and lightbulb each time)

Four people will have to draw their circuits on the board – if no one volunteers I will use the popsicle sticks to choose who has to go up.

Power worksheet from last time

We will do #10 and #11 on the board

Step 1: draw the circuits.

Applying Kirchoff’s Laws

• Most times, you will have the voltage and individual resistances. First, find the equivalent resistance of the circuit and then find the current leaving the battery.

• Next, you can apply Kirchoff’s laws to find what you are missing.

Circuit Simplifying Example

1. Find the current supplied by the battery

2. Find the voltage between points A and B

A

B

Homework/announcements

• The homework quiz will be first thing next class. There will be no time to review before the quiz. You have the rest of this class to ask questions and complete the HW set.

• For the take home test – the notebook check will be a quarter of your test grade.

Circuits Day 3

Warm up

• Clear your desk for the homework quiz.

Power Example

• Determine the power dissipated in the 5 Ω resistor in the circuit shown below

Hint: figure out the current or voltage of that resistor to use one of the power equations

Circuits Video

• Hewitt Video (on the USB drive)

Equivalent Resistance problems

• Arrange the following resistors to make1. Ω2. Ω3. Ω4. Ω5. Ω

Resistance in wires

• Short circuits

• Superconductors