RL Series circuits

Question 1

What is the formula to find total inductance (Lt) in a series circuit?

Answer 1

The total sum of all the inductance

Lt = L1 + L2 + L3……

Question 2

XL is measured in _____ and expresses the amount of __________ in the circuit

Answer 2

XL is measured in ohms and expresses the amount of opposition to current flow in the circuit

Question 3

If inductance increases, what else will increase or decrease?

Answer 3

As inductance increases, current decreases, and inductive reactance increases.

Question 4

How does frequency effect inductive reactance?

Answer 4

At higher frequencies, the magnetic field expands and contracts faster which provides more opposition to circuit current. As frequency increases, current decreases, and inductive reactance increases.

Question 5

Combining the effects of inductance and frequency produces what formula for inductive reactance?

Answer 5

Inductive Reactance = 2 x Pie x frequency x inductance

Question 6

What is the formula for finding total inductive reactance?

Answer 6

Total XL is determined by adding each inductor’s inductive reactance.

XLt = XL1 + XL2 + XL3…..

Question 7

What is the voltage drop across L1 in this pure inductive series circuit?

Answer 7

1st) Find Inductive Reactance Total (XLt)

L1 = 6mH

XL1 = (2)(pie)(frequency)(inductive)

= (2)(3.14)(10)(6)

XL1 = 376.8

L2 = 4mH

XL2 = (2)(pie)(frequency)(inductive)

= (2)(3.14)(10)(4)

XL2 = 251.2

XLt = XL1 + XL2

= 376.2 + 251.2

XLt = 628k ………(will act like a resistance for Ohm’s Law)

2nd) Find Total Current using Ohm’s Law

I (current) ?

x R (resistance) x 628 10 ÷628 = .01592

V (voltage) 10vac

3rd) Find Voltage Drop for L1

Voltage Drop = Total Current x XL1

= .01592 x 376.8

= 6

Question 8

The combined opposition to current flow from the resistor and inductor is called ____. The unit of measure is _____.

Answer 8

The combined opposition to current flow from the resistor and inductor is called impedance (Z). The unit of measure is ohms.

Question 9

The formula for total impedance (Zt)?

Answer 9

Zt = Sq Root of : Rt² + XL²

Question 10

What is the formula for applied voltage *after *total impedance (Zt) is calculated?

Answer 10

EA = Sq Root of: ER² + EL²

Question 11

In AC circuits with reactance, what are the three types of power?

Answer 11

Real - power consumed by the resistor.

Reactive - power in the inductor.

Apparent - the combination of real power and reactive power.

Question 12

In an RL series circuit, as the phase angle approaches 0 degrees, the circuit is mostly _______.

Answer 12

resistive

Question 13

In RL series circuits, current is the same at what points?

Answer 13

current is the same at any point in the circuit

Question 14

As XL increases, a circuit becomes more _______.

Answer 14

inductive

Question 15

In RL series circuits, voltage leads current by _______ degrees.

Answer 15

voltage leads current by 90 degrees

Question 16

When measuring across a resistor, _______ and _______ are always in phase.

Answer 16

voltage and current

Question 17

When XL is large compared to R in an RL series circuit, the circuit is _______.

Answer 17

inductive

Question 18

RL series circuits consist of _______ and _______ connected in series.

Answer 18

inductors, resistors

Question 19

In RL series circuits, R and XL oppose ______ at right angles.

Answer 19

oppose current at right angles

Question 20

In RL series circuits, ER and EL are at ______angles.

Answer 20

are at right angles

Question 21

In an RL series circuit, as the phase angle approaches 90 degrees, the circuit is mostly _______.

Answer 21

inductive