Flashcards in Basic Electricity Deck (54)

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1

## What constitutes a capacitor

### two conductors separated by an insulator

2

## What is the purpose of a capacitor

### It stores electrical energy in electrostatic fields

3

## Does a capacitor in an AC circuit cause the current to lead or lag the voltage

### It causes the current to lead the voltage

4

## The basic unit of a capacitor

### The farad

5

## The reason why an electrolytic capacitor can only be used in a DC circuit and not an AC circuit.

### They are polarized so they can only work in one direction. If current passes in the opposite direction, it will pass through the capacitor and overheat it (explode)

6

## What is meant by inductuance

### The ability to store electrical energy in electromagnetic fields

7

## The basic unit of inductance

### The henry

8

## What is an example of an inductor used in a magneto

### The primary and secondary coils

9

## Does an inductor in an AC circuit cause the current to lead or lag the voltage

### lags

10

## How can you find the polarity of an electromagnet

### Hold the electromagnet in your left hand with your fingers encircling the coil int he direction electrons flow (from negative to positive). Your thumb will point to the north pole

11

## What is meant by impedance

### Total opposition to current flow in an AC circuit. The vector sum of capacitive and inductive reactance and resistance

12

## What is the basic unit of impedance

### Ohm

13

## What are 5 sources of electrical energy

###
1. Light

2. Radiation

3. Chemical

4. Magnetism

5. Heat

14

## What is the basic unit of power in a DC circuit

### The watt

15

## What is meant by a megawatt

### 1,000,000 watts

16

## What is the formula for power in a DC circuit

### P=IV

17

## The relationship between mechanical and electrical power

### 1 horsepower= 746 watts

18

## What is meant by true power in an AC circuit

### The actual amount of power being used, or dissipated, in a circuit

19

## In what unit is true power expressed in

### Watt

20

## What is meant by apparent power in an AC circuit

### The combination of reactive power and true power is called apparent power, and it is the product of a circuit’s voltage and current, without reference to phase angle

21

## The basic unit of reactive power

### VAR (Volt amps reactive)

22

## What is meant by power factor in an AC circuit

### The ratio of true power to apparent power or the ratio of circuit resistance to circuit impedance

23

## What 2 things happen when current flows through a conductor

###
1. Heat is generated

2. Magnetic field surrounds the conductor

24

## The 4 factors that affect resistance of a conductor

###
1. Temperature

2. Length

3. Cross sectional area

4. Material

25

## What is meant by continuity in an electrical circuit

### The circuit is continuous so electrons can flow from one terminal to the next

26

## The 3 things that an electrical circuit must have in order to work

###
1. Supply voltage

2. Consumers

3. Conductors to join the consumers to the supply

27

## What would happen to the current in a DC circuit if length of the conductor doubled but all other factors remained the same?

### The current would decrease by half

28

## What is meant by the capacity rating of a lead-acid battery?

### The number of hours a battery can supply a given current flow

29

## What is the unit that a battery capacity is expressed in

### Ampere-hours

30