Chapter 18 POWERPOINT

Use the textbook to define these Technical Terms:

1. circuit

2. electric power

3. equivalent resistance

4. frame-ground circuit

5. ground

6. Ohm’s law

7. parallel circuit

8. series circuit

9. series-parallel circuit

10. watt

Use the textbook to answer these discussion questions:

1. Explain the operation of a frame-ground circuit.

Read the chapter summary below:

Summary

■The three basic types of circuits are series, parallel, and series-parallel circuits.

■ A series circuit has one or more loads connected in the same path.

■ A parallel circuit has two or more separate paths for current, and each path can operate independently of the others.

■ A series-parallel circuit has both series and parallel sections in one circuit.

■ Many automotive circuits are frame-ground or one-wire circuits. The vehicle’s metal structure is used to carry current back to the source. This reduces the amount of wire needed to complete the circuits.

■ Ohm’s law consists of a set of formulas that ex- press the relationships between voltage, current, and resistance in a circuit. If you know any two of the three values, you can use Ohm’s law to calculate the unknown value.

■ If circuit resistance increases, current decreases. If resistance decreases, current increases. If voltage increases, current increases also.

■ Current is the same everywhere in a series circuit. Total resistance is the sum of all series resistances. The voltage drop across each series resistance equals the applied voltage source.

■ In a parallel circuit, total circuit current is the sum of all branch currents. Total circuit resistance in a parallel circuit is less than any one branch resistance. The voltage applied to each branch is the same.

■ To find the equivalent resistance in a series- parallel circuit, evaluate the parallel section to find its total resistance, and then use the formula for series resistance.

■ Prefixes are commonly used to express very large or very small electrical values.