4 - Elec 2 Flashcards by Gold Fish

Basically an electrical circuit consists of ______, ______ and _____. A) B) C) D)

-Power source -connecting wires or conductors -load or something that uses the electrical energy

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The load is the device that takes electrical energy from the power source and ? A) B) C) D)

uses it to perform some useful function

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All switches perform the same basic function? A) B) C) D)

Opening and closing electric circuits

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The amount of voltage supplied by the source determines? A) B) C) D)

How much current will flow

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2 factors that determin how much current will flow in a DC circuit A) B) C) D)

-The voltage supplied and -How well the load and wires conduct current

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The ease with which a metal allows current to flow is? A) B) C) D)

conductance

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_____ has the greatest conductance? A) B) C) D)

Silver

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The resistance of any material depends on? A) B) C) D)

The number of free electrons the material has

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By choosing the proper metal for a conductor and making it with a certain cross-section and length? A) B) C) D)

You can produce any kind of resistance effect you want

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A unit of resistance is called? A) B) C) D)

Ohm

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The Greek letter ______ is often used for the symbol for the Ohm A) B) C) D)

Omega

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The resistance of the ______ is much greater than the resistance of the _____? A) B) C) D)

load; circuit wiring

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Every power source has some? A) B) C) D)

internal resistance

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Two possible methods of decreasing large current in a circuit with a fixed voltage are? A) B) C) D)

increasing the resistance of the connecting wires and adding resistors to the circuit

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The materials most often used for resistors are ______, and special metal alloys, such as nichrome, constantan and manganoan. A) B) C) D)

Carbon

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To account for variations resistors are marked with? A) B) C) D)

A tolerance

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The wattage rating on the resistor determines? A) B) C) D)

The maximum current a resistor can carry

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What are the advantages of a composition resistor? A) B) C) D)

smaller and low cost

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The property of maintaining a small tolerance under all operating conditions is called the ______ of a resistor A) B) C) D)

Stability

When all 3 terminals are connected into a circuit the resistor is called A) B) C) D)

potentiometer

When only the center terminal and one other terminal are used in a circuit the resistor is called? A) B) C) D)

Rheostat

If you raise voltage ( E), ______ will go up. A) B) C) D)

Current (I)

If you lower resistance ( R), _____ will go up. A) B) C) D)

Current (I)

A good practice to always follow at this point is to think in terms of? A) B) C) D)

Knowns and Unknowns

Power is the amount of ? A) B) C) D)

Work that can be done by a load in some standard amount of time

A watt is the power used when? A) B) C) D)

One ampere of current flows through a potential difference of one volt

The power rating of working equipment is based mostly on? A) B) C) D)

The power they can use to do mechanical work

Electric companies charge their customers according to the number of? A) B) C) D)

Kilowatt hours of power they use

1000 volts = A) B) C) D)

1 kilowatt

1,000,000 volts = A) B) C) D)

1 megawatt

In a series circuit the same _____ flows through every part A) B) C) D)

Current (I)

When 2 batteries are connected in series? A) B) C) D)

The negative terminal of one is connected to the positive terminal of the other

When power sources are connected in series the total voltage is? A) B) C) D)

The sum of the individual source voltages

If power sources are connected so that their polarities are not in the same direction? A) B) C) D)

They will oppose each other

The total voltage drop equals? A) B) C) D)

the source voltage

In a series circuit there in only one current it is from? A) B) C) D)

The negative terminal to the positive terminal

When current can flow from the negative terminal of the power source through the connecting wires and back to the positive terminal of the power source without going through a load, this is called? A) B) C) D)

short circuit

_____ uses the principle of magnetism to open a circuit when too much current flows? A) B) C) D)

Electro magnetic circuit breaker

A ____ circuit is where one or more points, the current divides and flows different paths points A) B) C) D)

parallel

The total current in a parallel circuit = A) B) C) D)

the sum of the branches current

This method can be used to calculate the total resistance of any combination of parallel resistance in a circuit? A) B) C) D)

reciprocal

The total power consumed in a parallel circuit = A) B) C) D)

the sum of the power used by each individual load

Kirchhoff's Law No 1 A) B) C) D)

The sum of the voltage drops around any closed loop equals the sum of the EMF's in that loop

Most resistor failures result from? A) B) C) D)

the heat generated in the resistor by the current flow

EMF is measured in? A) B) C) D)

volts

The longer the wire? A) B) C) D)

the more resistance it has

What determines the resistance of a given conductor? A) B) C) D)

-cross-sectional area -length of the conductor -resistance