Flashcards in PHEP 17 Deck (34)

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1

## What best defines a cycle

### two alternations, one in each direction

2

## How many times larger is the max voltage value than the effective voltage value

### 0.707

3

## what is another name for effective values

### root mean square value

4

## Does an AC amp produces heat at the same rate as a DC amp

### yes

5

## what is the direction of a vector indicated by

### a line segment and arrow

6

## what is the magnitude of a vector indicated by

### length of line

7

## in what direction is positive rotation of a vector

### counter clockwisewha

8

## what effect does self induced voltage have on applied voltage

### it opposes it and reduces effectiveness

9

## what variables determine inductive reactance

### 2pi constant, frequency, inductance

10

## what is the relationship between current and applied voltage in a purely inductive circuit

### current lags 90 degrees

11

## What are the two factors that limit current in an inductive circuit?

### inductive reactance and resistance

12

## in a purely inductive reactant and resistant circuit what is the current applied voltage relationship

### current lags by 45 degrees

13

## what are the units of capacity

### farrads

14

## what is power factor

### ratio of true power to apparent power

15

## AC meters and instruments are designed to read _____ voltage and currents.

### Effective.

16

## The effective values of voltage and current are equal to the maximum values multiplied by?

### .707

17

## The three factors that limit the flow of current in an AC circuit are?

###
1. Resistance

2. Inductive reactance

3. Capacitive reactance

18

## In a pure resistance circuit, voltage and current are?

### In phase.

19

## In an AC circuit, what represents total Opposition to current and what is the symbol?

### Impedance, Z

20

## What is the symbol for inductive reactance?

### XL

21

## Whats used to determine inductive reactance?

### The frequency and the amount of inductance in a circuit.

22

## What does ELI ICE represent?

###
ELI= voltage leads current (inductance)

ICE= current leads voltage (capacitve)

The letters represent the symbols for voltage, current, inductance, capacitance.

23

## Whats the relationship of voltage and current in a pure inductive circuit?

### Voltage leads current by 90 degrees.

24

## Capacitive reactance varies inversely with?

### The frequency and the size of the capacitor.

25

## In a pure capacitive circuit, voltage and current's relationship is?

### out of phase 90 degrees, with current leading.

26

## What does VARs stand for?

### Volt-ampere-reactive

27

## The power factor is equal to the cosine of the?

### angle of phase difference between voltage and current.

28

## What is the measurement of the primary harmonic?

### 60hz

29

## What increments do harmonics go by?

### 60

30