Parallel Circuits

What are the characteristics of a parallel circuit?

What happens to overall circuit resistance as more resistors are added in parallel?

What is Equivalent Resistance?

What are the general trends with a series and parallel circuit?

Type of Circuit / Resistance (W) / Current (A) / Potential Difference (V)
Series
Parallel

What is a VIRP table?

Resistance (W) / Current (A) / Potential Difference (V) / Power (W)
R1
R2
Battery

Trends in a Parallel circuit:

·  What happens to potential difference when resistance is small?

·  What happens to potential difference when resistance is big?

·  What happens to current when resistance is small?

·  What happens to current when resistance is big?

·  How does current split when resistors are identical?

·  How does current split when resistors are different?

Practice Questions

1.  The equivalent resistance of three 4- Ω resistors in parallel is _____.

2.  Does current flow through a resistor, or across a resistor? Is voltage established through a resistor or across a resistor?

3.  Does current in the lamps occur simultaneously, or does charge flow first through one lamp, then the other, and finally the last in turn? ______

4.  What is the equivalent resistance of the circuit three resistors with the values 36-W, 20-W, and 63-W if you connect them in parallel?

5.  What is the equivalent resistance of the circuit three resistors with the values 56-W, 62-W, and 45-W if you connect them in parallel?

6.  Consider a set of resistors with resistances equal to 4.5W, 14.0W and 16.0W. What values of the equivalent resistance can be obtained by connecting any two of them in different parallel connections?

7.  Complete the VIRP tables below. This symbol is a resistor:

a.  Circuit 1

Resistance / Current / Voltage / Power
1 / 2 Ω
2 / 4 Ω
3 / 6 Ω
Total / 12 V

b.  Circuit 2

Resistance / Current / Voltage / Power
1 /

6 Ω

2 / 3 Ω
Total /

6V

Notes_ParallelCIrcuits.doc