Instruction 7-4

Predict the Voltage of Current | Ohm's Law Problems | Kirchoff's First Law | Kirchoff's Second Law | Transistors | Summary

“The algebraic sum of the changes in potential around any closed path of a circuit must be zero.”

This means that when you look at the resistors in series, the drop in voltage across all of them will be equal to whatever the source is.

The gray boxes represent different parts in a circuit. The loop rule says that sum of the changes in potential around any closed path of a circuit must be zero. That means that

Check out the second law at the website below.

http://regentsprep.org/Regents/physics/phys03/bkirchof2/default.htm

It is helpful to keep in mind the following tips when analyzing circuits using Kirchoff's 2 laws.

1. Draw the circuit and label the known and unknown quantities. You have to assign directions to the currents and it will not matter if you guess wrong. It will turn out to have the correct magnitude.
    
2. Apply the junction rule to as many junctions that you can to get the most independent relations.
    
3. Apply the loop rule to as many loops in the circuit as necessary in order to solve for unknowns.
    
4. Solve the set of equations for the unknown quantities.

Video Instruction
*Availability of You Tube video links may vary. eTAP has no control of these materials.

• Circuits Part 1, Series Circuit [11:39]

• Circuits Part 2, More Complicated Series Circuit [11:08]

• Circuits Part 3, Parallel Circuits [12:20]

• Circuits #4, More Complicated Parallel Circuit [7:07]

• Kirchhoff’s Rules [9:31]

• Series and Parallel Circuits [10:55]

• How To Build A Series Circuit [1:51]

for Students, Parents and Teachers

Now let's do Practice Exercise 7-4 (top).

Next Page: Transistors (top)