3.15 AC Resistors Flashcards
What is a effective resistance or ohmic resistance?
A resistor which has the same effect in both AC circuit and DC circuit
What is inductive reactance?
The result of an AC in a coil causing a self induced voltage. This self-induced voltage opposes the applied voltage and therefore reduces the effective voltage causing the current to decrease
In a circuit with only inductive reactance (ideal coil) the current lags the applied voltage by……
90°
Inductive reactance equation
Inductive reactance XL = 2 π f L
XL Inductive reactance in Ω
f Frequency in Hz
L Inductance in H
Capacitors are not used in what type of circuit?
DC
In an AC circuit a capacitor behaves like a?
Resistance
Referred to as capacitive reactance
What happens to a capacitor every time the polarity in an AC circuit changes?
The capacitor is charged and discharged
What happens to a capacitor during charging?
The capacitor draws energy (reactive energy) during the charging process and stores it for a short time in the electric field
In a circuit with only capacitive reactance (ideal capacitor) the current …………… the applied voltage by ……….
Leads by 90°
The capacitive reactance of a capacitor ……………. as the capacitance of the capacitor increases and as the frequency increases.
Decreases
Effective frequency is not dependent on?
Frequency
The inductive reactance increases in proportion to the?
Frequency of the applied AC.
The capacitive reactance increases in inverse proportion to the?
Frequency
Inductive reactance equation
X L = 2π x f x L
Capacitive reactance equation
Xc= 1/ 2π x f x C
What is impedance?
A measure of the opposition to electrical flow
(The total resistance of a coil in an AC circuit consists of the effective resistance (winding resistance) and the inductive reactance.)
Impedance equation
Z = V/I
If a resistor and a capacitor are placed in series with each other and subjected to an AC, then?
The same sinusoidal current with the RMS value current flows through both
A series resonant circuit consists of:
A coil and a capacitor connected in series
Electronical resonance
Occurs in an electric circuit at a particular resonant frequency when the impedances or admittances of circuit elements cancel each other
