1. Principles & Applications
Electricity
Principles & Applications
Sixth Edition
Richard J. Fowler
Chapter 4
Circuit Components
© Glencoe/McGraw-Hill

2. INTRODUCTION Cell Characteristics Testing Lamps Resistor Color Codes
Types of Switches
Testing Fuses

3. Cell Characteristics Volts 2.8 Lithium 1.5 Silver oxide 1.25
Nickel-cadmium
Alkaline-
manganese dioxide
Carbon-zinc
% of discharge

4. Testing a Lamp When the lamp is not blown, its resistance
<1kW µW
When the lamp is not
blown, its resistance
will be less than one
kilohm.
When the lamp is blown (open), its resistance will be infinite.

5. Neon Lamp The next slide shows how a neon lamp responds to dc,
then to ac, and then again to dc.

6. Click on the image to run the display.
To rerun the display, click again on the image.

7. Operation of a Flasher Lamp
Just click the
mouse one time
and watch the
action!
Cell
OFF ON

8. Operation of a Flasher Lamp
Cell ON
OFF
The flashing will discontinue when the lamp is turned off.

9. Exploding Neon Lamp
The next slide shows what can happen to a neon lamp when the current limiting resistor shorts out.

10. Click on the image to run the display.
To rerun the display, click again on the image.

11. Cell and Lamp Quiz The ____ cell has the most output voltage. lithium
The ____ cell has the least output voltage.
nickel-cadmium
The ____ cell’s voltage drops most
rapidly when it is discharging.
carbon-zinc
The nominal voltage of the alkaline-
manganese dioxide cell is ____ volts.
1.5
A blown lamp has a(n) ____ resistance.
infinite

12. Resistor Color Codes
Yellow 4 7
Violet 00
Red
±10 %
Silver

13. Resistor Color Codes 56 x 103 ± 5 % = 56000 ± 5 % = 56 kW ± 5 %
Green = 5
Blue = 6
Orange = 3
Gold = ± 5 %
56 x 103 ± 5 % =
56000 ± 5 % =
56 kW ± 5 %

14. Resistor Color Codes
= 464 kW ± 2% 4 6 4
0 0 0
± 2%

15. Overheated Resistor
The next slide shows what can happen when the power rating of the wire-wound resistor shown below is greatly exceeded.

16. Burning Resistor Click on the image to run the display.
To rerun the display, click again on the image.

17. Toggle Switches Single-pole, single-throw (SPST)
Single-pole, double-throw
(SPDT)
Double-pole, single-throw
(DPST)
Double-pole, double-throw
(DPDT)

18. Rotary Switches OR OR Single-pole, three-position (SP3P)
Double-pole, three-position
(DP3P)

19. Make-Before-Break (Shorting) Switch
In position 1

20. Make-Before-Break (Shorting) Switch
In transition from position 1 to position 2

21. Make-Before-Break (Shorting) Switch
In position 2

22. Testing a Fuse When the fuse is not blown, its resistance
will be less than one
ohm.
When the fuse is blown (open), its resistance will be infinite.

23. Slow-Blow Fuse This material connects the fuse element sections
together. When the over-current is small, the
alloy slowly softens and weakens. Then the
spring
pulls the element sections apart.
Spring
When the over-current is extremely large,
this section immediately burns open.

24. Blown Fuse (1st case) This slow-blow fuse was blown by
a very large over-current. Notice
that the spring is still in place.

25. Blown Fuse (2nd case) This slow-blow fuse was blown by
a small over-current. Notice that
the spring has retracted a section
of the fuse element.

26. Slow-Blow Fuse in Action
Watch the alloy melt and the spring retract.
Click on the image to run the display.
To rerun the display, click again on the image.

27. Resistor, Switch and Fuse Quiz
A resistor with yellow, violet, red, and gold
bands has a resistance of ____ kilohms.
4.7 ± 5%
A resistor with red, red, red, red, and red
bands has a resistance of ____ kilohms.
22.2 ± 2%
The ____ switch can provide the most
switching functions.
rotary
The ____ switch can be either a shorting
or a non-shorting switch.
rotary
A fuse with infinite resistance is a ____ fuse.
blown

28. REVIEW Cell Characteristics Testing Lamps Resistor Color Codes
Types of Switches
Testing Fuses