RLC

Question 1

Inductance opposes a change in _____

Answer 1

Current

Question 2

Inductance of a coil is not effected by the _____

Answer 2

Frequency of applied voltage

Question 3

To find inductive reactance of a circuit you must know _____ and ______

Answer 3

Frequency and inductance

Question 4

There is no phase difference between current and voltage across ____
A. Inductor
B. Resistor

Answer 4

Resistor

Question 5

Capacitance opposes the change in _____

Answer 5

Voltage

Question 6

In series RC, the voltage across the resistor is in phase with the current, true or false?

Answer 6

True

Question 7

If a series is resonant, circuit impedance is equal to _____

Answer 7

Circuit resistance

Question 8

Capacitors in parallel add _____

Answer 8

Directly.

C1 + C2 + C3

Question 9

Capacitors in series add _____

Answer 9

Inversely

Question 10

When a circuit is pure resistance the PF is _____

Answer 10

1

Question 11

In a parallel resonant circuit the impedance is at a _____ and line current is at a _____

Answer 11

Maximum, minimum

Question 12

In a series resonant circuit the impedance is at a _____

Answer 12

Minimum

Question 13

When frequency of an inductive circuit increases, the current ______

Answer 13

Decreases

Question 14

In AC capacitance, the current varies directly with the _____

Answer 14

Frequency

Question 15

XL =

Answer 15

2pi • f • L

Question 16

L=

Answer 16

XL / 2pi • f

Question 17

Q factor =

Answer 17

XL / R

Question 18

R = Esquared / P

Transpose

Answer 18

P = E squared / R
P = I squared / R

Question 19

Fr =

Answer 19

1 / 2pi • square root LC

Question 20

When comparing DC and AC circuits, the DC value will always be what part of the vector?

Answer 20

X axis (resistance)

Question 21

When comparing DC and AC circuits, AC values will always be on what part of the vector?

Answer 21

Hypotenuse

Question 22

Two principal parts of a capacitor

Answer 22

Plates, dielectric

Question 23

Two principal parts of an inductor

Answer 23

Coil, core

Question 24

There is no inductance in a DC inductive circuit after five time constants. T/F?

Answer 24

True.

Question 25

What is the danger of putting an inductor in a DC circuit?

Answer 25

The current can be dangerously high

Question 26

What side of impedence triangle is impedance?

Answer 26

Hypotenuse

Question 27

What side of impedance triangle is reactance?

Answer 27

Opposite

Question 28

What side of impedance triangle is resistance?

Answer 28

Adjacent (x axis)

Question 29

Henries add ______ in series

Answer 29

Directly

Question 30

Henries add _______ in parallel

Answer 30

Inversely

Question 31

Capacitors add _______ in series

Answer 31

Inversely

Question 32

Capacitors add ________ in parallel

Answer 32

Directly

Question 33

In induction any change in current means change in flux. T/F?

Answer 33

True

Question 34

Inductance is the property of a circuit that opposes any change in current in that circuit. What does this mean for current?

Answer 34

If current increases, induced EMF will try to push it back down. If current decreases induced EMF will try to push it back up.

Question 35

Induced voltage opposes applied voltage. T/F?

Answer 35

True.

Question 36

A voltage is induced across the conductor when ______

Answer 36

The magnetic field collapses

Question 37

How do you prevent a dangerous arc at a switch when opening a DC inductor?

Answer 37

Free wheeling diode or field discharge resistor

Question 38

How does a free wheeling diode work?

Answer 38

Before a free wheeling diode is installed when the switch is opened the inductor will try to maintain current slow causing an arc across the switch. When the FwD is added into the circuit the inductor acts as a source, the polarity of the FWD changes and now current will flow through the diode until all energy is dissipated instead of arching.

Question 39

How to calculate current after ___seconds.

Answer 39

I = t • E/L Ex) I = 10s • 20V/10H = 20A

Question 40

What is the main effect of an inductor in a DC circuit?

Answer 40

To slow rate of current rise.

Question 41

What is the formula for tau?

Answer 41

L/R

Question 42

Capacitors oppose a change in ______

Answer 42

Voltage

Question 43

What will happen to current of a capacitor when source is changed from AC to DC?

Answer 43

It will decrease. DC does not change polarities so the capacitor cannot discharge

Question 44

What happens to XL when turns increase?

Answer 44

Increases

Question 45

How many decimal places to move for micro farads

Answer 45

6

Question 46

In non resonance and resonance do the watts of the resistor change?

Answer 46

Yes

Question 47

Formula for L

Answer 47

XL / 2pif Write this down

Question 48

When converting an equation to resonance, which value do you keep?

Answer 48

Frequency, resistor resistance

Question 49

When frequency is increased, inductance _______ and capacitance _______

Answer 49

Increases, decreases

Question 50

When resistance and inductance is on the same angle, the PF is

Answer 50

100%

Question 51

When calculating motor input and output, what is the process of calculating the three values by pf and ef?

Answer 51

hp x 746 gets output, divide output by efficiency, that value is watts. Divide watts by power factor, that value is input.

Question 52

Where do you put the value of watts from the motor?

Answer 52

Watts calculated from the motor goes on watts of the resistor of the motor when broken down between resistor and inductor.

Question 53

Where do you put the value of input when calculating motor?

Answer 53

Input value is the VA of the motor WIRE

Question 54

Where do you find the VaR of the inductor on the motor wire?

Answer 54

Input squared minus watts squared

Question 55

When looking at a sine wave, what do the block lines represent?

Answer 55

1 alternation

Question 56

How many degrees is 1 alternation?

Answer 56

180

Question 57

How do you calculate the angle of a sine wave?

Answer 57

Find amount of blocks in 1 alternation. 180/# of blocks = degree of each block. Count blocks between different sine waves and multiple degrees by that amount.