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CHAPTER 4 – CIRCUIT COMPONENTS
NAME:
DATE:
Define each of the following terms from Chapter Four of the text book. Read the passages and include any additional
information that may assist you on an exam such as symbols or base units. Some of the terms may need to be defined
by reading the surrounding text.
Battery
Cell
Electrodes
Electrolytes
Ampere-Hours
Secondary Cells
Dry Cell
Wet Cell
Internal Resistance
Cell (or battery) capacity
Depolarizing agent
Group of plates
Rate of charge
Specific Gravity
Chapter 4 – Circuit Components
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Hydrometer
Charge/discharge cycles
Shelf life
Voltage standard
Light loads
Light-emitting diodes
Neon glow lamps
Incandescent lamps
Tungsten filament
Life
Rated voltage
Lumens
Current ratings
Ionization
External Resistor
Current-limiting resistors
Chapter 4 – Circuit Components
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Polarized device
Potentiometer
Nonlinear tapers
Rheostats
Adjustable resistors
Tapped resistors
Power rating
Safety factor
Tolerances
Color codes
Surface-mount devices
Reliability
Normally open
Normally Closed
SPDT
Rotary switches
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Shorting
Cable
Wire
Solid Conductor
Stranded Conductor
Shielding
Coaxial cable
Flat ribbon
Gage number
Maximum temperature rating
Short circuit
Dead short
Grounded
Current rating
Fuse
Blowing characteristic
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Fast-blow fuses
Medium-blow fuses
Slow-blow fuses
Instrument fuses
Resettable fuses
Thermal circuit breakers
Magnetic circuit breakers
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Cells are energy or power sources.
Cells provide dc voltage.
A cell contains an electrolyte and two electrodes.
A battery is made from two or more cells.
Primary cells are not rechargeable.
Secondary cells are rechargeable.
Dry cells may use either a paste or a liquid electrolyte.
Gases are produced when cells are charged or discharged.
The energy storage capacity of a cell or battery is expressed in ampere-hours.
The energy available from a battery is dependent on temperature, rate of discharge, and final voltage.
Internal resistance causes a cell's voltage to decrease as the current increases.
Polarization refers to the buildup of gas ions around an electrode.
Common secondary cells are lead-acid, nickel-cadmium, and rechargeable alkaline.
Common primary cells are carbon-zinc, alkaline, mercury, and silver oxide.
When a lead-acid cell is discharging, sulfuric acid is being converted to water.
Specific gravity is measured by a hydrometer.
Safety glasses should be work when working with lead-acid cells and batteries.
Electrolyte on the skin or clothing should be immediately removed by flushing with lots of water.
Carbon-zinc cells are relatively inexpensive.
Alkaline cells store more energy than carbon-zinc cells. The former are more efficient at high current drains.
Both mercury and silver oxide cells have nearly constant output voltage.
Incandescent miniature lamps have tungsten filaments.
Miniature lamps have both a current and a voltage rating.
Bimetallic strips bend because the two metals have different coefficients of expansion.
The resistance of a lamp when hot is greater than its resistance when cold.
Only one electrode glows when a neon lamp is operated on direct current.
Both a neon lamp and a light-emitting diode (LED) circuit must have a resistor to limit the current through the device.
A potentiometer is a variable resistor.
A potentiometer can also be used as a rheostat.
The power rating of a resistor is independent of its resistance.
Common types of resistors are carbon-composition, cermet, wire-wound, deposited-film, and conductive-plastic.
Chapter 4 – Circuit Components
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Resistance values and tolerances are indicated with a color code on the body of a resistor.
Thermistors have high temperature coefficients.
Common types of small switches are rotary, toggle, slide, rocker, and push-button.
Spring-loaded, momentary-contact switches can be either normally open or normally closed.
Rotary switches can handle complex switching involving many circuits.
Switches have both a current and a voltage rating.
Cables are multiple conductors.
Wires are single conductors.
Conductors may be stranded or solid.
Shielded wires and cables are used to help isolate a conductor's electromagnetic fields.
Coaxial cables are used to connect antennas to receivers or transmitters.
The American wire gage is the standard used to specify the size of a conductor.
The cross-sectional area of a conductor is specified in circular mils.
When the gage of a conductor is decreased by three gage numbers, its cross-sectional area doubles. Its resistance is
half as much.
Insulation used on conductors has both a temperature and a voltage rating.
Circuit-breaker mechanisms work on either a magnetic or a thermal principle.
Fuses are thermally operated devices.
A blown fuse results in an open circuit.
Instrument (fast-blow) fuses are used to protect electric meters.
Resettable fuses do not produce an open circuit when tripped.
SMDs are smaller than traditional components.
Fuses and breakers have both current and voltage ratings.
The characteristics of various dry cells are given in Table 4-2.
Table 4-2
Cell Type
Carbon-zinc
Alkaline
Mercury
Silver oxide
Lithium
Rechargeable
alkaline
Nickel-cadmium
Dry Cell Characteristics
Rated
Voltage during
Voltage Discharge
1.5
1.5
1.35
1.5
2.5 - 3.6
1.5
Decreases
Decreases
Almost constant
Almost constant
Almost constant
Decreases
1.25
Decreases
slightly
Chapter 4 – Circuit Components
Cycle
Life
Initial
Cost
Energy-toWeight Ratio
Low
Low
Med
High
High
High
Med
Internal
Resistanc
e
Med
Low
Low
Low
Med high
Very low
High
High
Very low
Low
Med
Med
High
High
Very high
Low
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