Unit 22 Capacitance in AC Circuits Flashcards
■ In a pure capacitive circuit, the voltage and current are ———with each other.
90 Degrees out of phase
■ In a pure resistive circuit, the voltage and current are—————-with each other.
in phase
■ In a circuit containing resistance and capacitance, the voltage and current will be out of phase with each other by some amount between
Zero degrees and 90 drgees
True power can be produced by
resistive parts of the circuit only.
■ Power factor is the ratio of
true power to apparent power.
In a pure capacitive circuit, does the current lead or lag the voltage?
Lead the voltage
The amount of resistance compared with the inductive reactance determines the quality (Q) of the coil.
Inductors that have a higher ratio of inductive reactance to resistance are considered to be inductors of higher quality.
Although inductors have some amount of resistance, inductors that have a Q of 10 or greater are generally considered to be pure inductors.
Once the
ratio of inductive reactance becomes 10 times as great as resistance, the amount of resistance is considered negligible.
For example, assume an inductor has
an inductive reactance of 100 ohms and a wire resistance of 10 ohms.
This total current-limiting effect is called impedance and is symbolized by the letter
Z.