Rlc

Question 1

Only use R ( resistance ) in DC circuit when calculating current

Answer 1

Yes!!!!!! I = E/R

Current = volts divide resistance

Question 2

Only use (z) impedance in AC CIRCUIT when calculating current

Answer 2

I=E/Z

Current = volts divide impedance

Question 3

Power factor equation

Answer 3

Pf= watts/VA

Watts(true power) divide by apparent power (VA)

Question 4

What is AC effective resistance

Answer 4

Dc ohmic value plus shred effects on conductor = AC EFFECTIVE

Question 5

How to test AC EFFECTIVE RESISTANCE

Answer 5

Wattmetre and ammetre

Question 6

Bc hydro adds surcharge for anything that operates under what % power factor

Answer 6

90%

Question 7

Impedance = AC OR DC?

Answer 7

Impedance ONLY in AC!

Impedance (z)
I = e/z

Question 8

Resistance AC or DC?

Answer 8

Both but when calculating current only in DC use resistance

I = E/R

Question 9

On right triangle what goes on hypotenuse (3 values )

Answer 9

Voltage
Apparent power
Impedance

Question 10

On triangle what goes on adjacent ( 3 values)

Answer 10

Resistance (ohms)
True power (watts)
Er (volts resistance)

Question 11

On triangle what goes on opposite (3 values)

Answer 11

Reactance (XL)
Reactive power (RP)
Volts across Reactance (Exl)

Question 12

What do we not use in AC when calculating current?

Answer 12

Do not use resistance! Only impedance (z)

Question 14

Point in sin wave where rate of change is greatest?

Answer 14

0 and 180 degrees

Question 15

Point in sinwave where rate of change is least?

Answer 15

90 and 270 degrees

Question 16

Inductance only effects cct when magnitude of _______ is changing

Answer 16

Current

Question 17

In DC current only changed when what?

Answer 17

Switch open or closed

Question 18

In AC current changes when

Answer 18

It’s always changing magnitude and direction through fill sinewave

Answer 19

It’s always changing magnitude and direction through fill sine wave

Question 20

What is pure inductive circuit?

Answer 20

Only quantity in circuit is inductance (no resistance)

Triangle is straight line = opp/hyp are equal

Question 21

What is pure resistive cct?

Answer 21

Only resistance and all power and voltage is dissipated by resistor (light/heater/toaster)

Triangle is straight horizontal line = adj and hyp are equal

Question 22

Phase angle between current and voltage in resistive cct

Answer 22

0 (both in phase with each other)

Question 23

Phase angle between current and voltage in inductive cct?

Answer 23

90 degrees ( current lags voltage by 90)

Question 24

Phase angle if cct has resistance and inductive reactance?

Answer 24

Between 0-90 degrees. Needs to be calculated

Question 25

Opposition to current in purely resistive cct?

Answer 25

Resistance

Question 26

Opposition to current in purely inductive cct?

Answer 26

Inductive reactance

Question 27

What is inductive reactance directly proportional to?

Answer 27

Frequency and inductance

Question 28

More resistance in a cct what happens

Answer 28

More resistance = current and voltage come more in phase with each other

Question 29

Impedance (Z) is a combination of what?

Answer 29

Resistance (R) and inductive reactance (XL)

Question 30

What types of power to practical inductors produce?

Answer 30

True power and reactive power = 90degree out of phase

Question 31

Apparent power (VA) combination of ..?

Answer 31

True power (watts) and reactive power (VAR)

Question 32

Another name for Q factor?

Answer 32

Figure of merit

Question 33

What is Q factor measurement of

Answer 33

Energy wasted- rate of dissipation

Question 34

Q factor is directly proportional to what?

Answer 34

Frequency of ac supply

Question 35

When voltage is POSITIVE and current is NEGATIVE power will be?

Answer 35

NEGATIVE POWER

Question 36

When voltage and current are both positive or negative we get what power?

Answer 36

POSITIVE power

Question 37

Another term for reactive power?

Answer 37

Wattless power

Question 38

Why are VAR’s called lagging VAR’s

Answer 38

VAR lags behind voltage inductive cct

Question 39

What does wattmeasure measure

Answer 39

True power in watts. It’s a combination of voltmeter and ammeter p= I X E

Question 40

Voltage coil connected in_______ Ammetre connected in __________

Answer 40

Volt = parallel with load Ammetre = series with load

Question 41

What power factor will purely resistive cct have?

Answer 41

100% power factor and phase angle of 0

Question 42

What power factor will purely inductive cct have?

Answer 42

Power factor 0% and phase angle of 90

Question 43

Heat loss is a form of what power?

Answer 43

True power and can be measured in watts

Question 44

1hp =

Answer 44

1hp =746 watts

Question 45

1hp =0.746 kW

Question 46

Inductance in series in parallel =

Answer 46

Same as resistance. Adds in series/ adds inversely in parallel

Question 47

Capacitance in series and parallel?

Answer 47

Opposite of resistance = series adds inversely / parallel = adds up

Question 48

As inductance decreases what happens to current?

Answer 48

It increases! Inversely proportional

Question 49

Inductance decreased what happens reactance ?

Answer 49

It decreased also ( directly proportional)

Question 50

Inductance and inductive reactance are directly proportional T/F

Answer 50

True!

Question 51

Current and impedance are inversely proportional T/F?

Answer 51

True

Question 52

What two factors vary change in inductive reactance?

Answer 52

Frequency and inductance of coil

Question 53

Adding inductors in parallel = what happens to total inductance?

Answer 53

Total inductance halves Reactance halves

Question 54

Adding inductors in series= what happens to inductance?

Answer 54

Total inductance doubles Reactance doubles

Question 55

Inductor ELI means?

Answer 55

Voltage leads the current E leads I

Question 56

Capacitor ICE means

Answer 56

Current leads voltage I leads E

Question 57

Inductive reactance is directly proportional to frequency T /F

Answer 57

True as frequency goes up, inductance goes up

Question 58

Capacitive reactance is Directly or inversely proportional to frequency?

Answer 58

Inversely proportional. As frequency increases, capacitance decreases

Question 59

What is resonant frequency?

Answer 59

The point on sine wave in a AC series circuit where inductive reactance and capacitive reactance cancel each other out

Question 60

In a purely capacitive cct voltage lags current by what angle?

Answer 60

90 degrees

Question 61

In purely inductive cct current lags voltage by what angle

Answer 61

90 degree

Question 62

Voltage has no effect on reactance true or false?

Answer 62

True!

Question 64

Capacitance in farads ‘c’ add inversely BUT XC add straight up in series… T/F

Answer 64

True! Only add farads inversely use XC to add straight up

Question 66

True power and frequency are