RLC Circuit - Voltage drop across Inductor

• calvert11
In summary: Now I understand that it's because the voltages are in antiphase. In summary, the voltage drop across the inductor can be found using the equation "pd = I*XL" and the voltages across the inductor and capacitor are in antiphase.

Homework Statement

A 10 μF capacitor and a 25 H inductor are connected in series with a 60 Hz source whose rms output is 112 V.

Find the voltage drop across the inductor. Answer in units of V.
Note: Sigfigs do not matter

Homework Equations

I = V/Z where Z is the impedence

XL = omega*L
XC = 1/omega*C

The Attempt at a Solution

I assumed the closed circuit was connected thus: battery to the capacitor, the capacitor to the inductor, the inductor to the battery.

I found the current using equation I = V/Z (the answer was correct)

I found the voltage drop across the capacitor by the equation V - I*XL = $$\Delta$$V (the answer was correct)

For the voltage drop across the inductor I tried I*XC - V. The answer is incorrect.

Could anyone tell me what I'm doing wrong?

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The voltage across the inductor leads the current by pi/2.
The voltage across the capacitor lags the current by pi/2.

So the voltages are in antiphase, and it is the difference between them
(not the sum) which is equal to the source voltage.

But having found the current, you can simply apply pd = I*XL to get the
voltage across the inductor.

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davieddy said:
So the voltages are in antiphase, and it is the difference between them
(not the sum) which is equal to the source voltage.
Thank you, this explains a lot. My answer would have been "pd = I*XL" but I thought it didn't make sense since it was greater than the source voltage.

1. What is an RLC circuit?

An RLC circuit is an electrical circuit that contains a resistor (R), an inductor (L), and a capacitor (C). These three components are connected in series or parallel, and they interact with each other to create a resonant circuit with a specific frequency response. RLC circuits are commonly used in electronic devices such as radios, televisions, and computers.

2. How does an RLC circuit work?

In an RLC circuit, the resistor limits the current flow, the inductor stores energy in the form of a magnetic field, and the capacitor stores energy in the form of an electric field. When an alternating current is applied to the circuit, the inductor resists changes in the current, and the capacitor resists changes in the voltage. As a result, the RLC circuit creates a specific frequency response based on the values of R, L, and C.

3. What is the voltage drop across an inductor in an RLC circuit?

The voltage drop across an inductor in an RLC circuit is directly proportional to the rate of change of current through the inductor. This means that as the current increases, the voltage across the inductor also increases, and vice versa. The voltage drop across an inductor can be calculated using Ohm's Law, which states that voltage (V) equals the product of current (I) and resistance (R), or V = I x R.

4. How does the inductor affect the voltage drop in an RLC circuit?

The inductor's property of storing energy in the form of a magnetic field causes it to resist changes in the current passing through it. This results in a voltage drop across the inductor that is in phase with the current. The inductor also has an impedance, which is a measure of how much it resists the flow of current. The higher the impedance, the larger the voltage drop across the inductor will be.

5. What are some common applications of RLC circuits?

RLC circuits have a wide range of applications in electronics and electrical engineering. They are commonly used in radio frequency (RF) circuits, audio amplifiers, power supplies, filters, and oscillators. RLC circuits are also used in communication systems, such as telephones, televisions, and radios, to filter out unwanted frequencies and enhance the desired signals.