Peak Voltage across capacitor

In summary, a coil connected to a 60 Hz ac generator with a peak emf of 80 V has an impedance of 14 ohm and a reactance of 12 ohm. The peak current in the coil is 5.71 Amps and the phase angle between the current and applied voltage is 58.99 degrees. To have a phase angle of zero, a capacitance of 349.02 microfarads is required to be added in series with the coil and generator. The voltage across the capacitor would then be measured.
  • #1
hitman0097
31
0

Homework Statement


A coil is connected to a 60 Hz ac generator with a peak emf equal to 80 V. At this frequency the coil has an impedance of 14 and a reactance of 12 .
a.) What is the peak current in the coil?
answer-5.71 Amps

b.)What is the phase angle between the current and the applied voltage?
answer-58.99 degrees

c.)A capacitor is put into series with the coil and the generator. What capacitance is required so that the current is in phase with the generator emf?

d.) What then is the peak voltage measured across the capacitor?

Homework Equations


I=V/Z = 80/14=5.17
phase angle [tex]\delta[/tex]=arcsin(X/Z)=arcsin(12/14)=58.99
Resonance, XL=XC; [tex]\omega[/tex]res=1/((LC)^.5)) omega is angular Freq, L is Inductance, C is capacatance.


VL=I*XC

The Attempt at a Solution


confused
 
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  • #2
What's the impedance of a capacitor, and what do impedances do when they are added in series? What kind of impedance do you want to have a phase angle of zero?
 
  • #3
Why don't people ever finish these forums, I have been stuck on this problem for an hour just part d.

A coil is connected to a 60 Hz, 100 V ac generator. At this frequency the coil has an impedance of 10 ohm and a reactance of 7.6 ohm.

(a) What is the current in the coil?

10 A

(b) What is the phase angle between the current and the applied voltage? (Calculate the angle in degrees.)

49.46 degrees

(c) What series capacitance is required so that the current and voltage are in phase?

349.02 micro FF

(d) What then is the voltage measured across the capacitor? The impedence would be a total of XC + XL = Z, but then how is the voltage drop reached?
 

1. What is an AC circuit?

An AC (alternating current) circuit is a type of electrical circuit that carries an alternating current, meaning the direction of the current changes periodically. This is in contrast to a DC (direct current) circuit, where the current only flows in one direction.

2. What is the difference between series and parallel AC circuits?

In a series AC circuit, all of the components are connected in a single loop and the current flows through each component in sequence. In a parallel AC circuit, the components are connected in multiple branches and the current is divided among them. This means that the total current in a parallel circuit is equal to the sum of the currents in each branch.

3. How do I calculate the total impedance of an AC circuit?

The total impedance of an AC circuit is the combined effect of resistance, capacitance, and inductance. To calculate it, you can use the formula Z = √(R² + (XL - XC)²), where Z is the total impedance, R is the resistance, XL is the inductive reactance, and XC is the capacitive reactance.

4. How does frequency affect an AC circuit?

The frequency of an AC circuit is the number of complete cycles the current goes through in one second. As the frequency increases, the reactance of inductors and capacitors also increases. This means that the impedance of the circuit will change, as well as the current and voltage. In addition, higher frequencies can cause energy losses and heating in the circuit.

5. What is the difference between AC and DC voltage?

The main difference between AC and DC voltage is that AC voltage periodically changes direction, while DC voltage always flows in the same direction. AC voltage is typically used for long-distance power transmission because it can easily be stepped up or down with transformers, while DC voltage is used for electronic devices that require a steady power supply.

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