Series LC circuit and voltage magnification?

In summary, the voltage across each component will be: I X R = VL1 = 111 V, I X R = VL2 = 223 V, and the total current is .005 amps.
  • #1
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I am trying to figure out what the voltage across each component will be. In the cirucit above resonance occurs between inductor L1 (5 Henries) and Capacitor C1 (10nF) The other inductor (L2) is 10 Henries and the circuit's resistance is 1,000 Ohms.

Here's my attempt at figuring the voltage magnification, total current, and voltage across each component.

Fres=711 Hz
XL1= 22.3 K Ohms
XL2= 44.6 K Ohms
XC1= 22.3 K Ohms

The Q of the circuit is XC or XL divided by R

Q= 22,300 / 1,000 = 23

Voltage magnification is Q times Applied Voltage. The applied voltage is 10V so the voltage magnification is 10 X 23 = 230V.

The circuit's total impedance at resonance is 44.6 K ohms + 1 K Ohm = 45,600 Ohms.
The total current is then V/R=I
I= 230 / 45,600 = .005 amps

So the voltage across each component is I X R = V

VL1 = 111 V
VL2 = ?
VC1 = 111 V

Inductor L2 has the highest reactance, so it should have the highest voltage drop right? Using ohms law the voltage drop across inductor L2 is 223 Volts which is obviously wrong.

What am I doing wrong here, and how do I find the current through the circuit and the voltage across each component? PLEASE HELP!
 
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  • #2
You've left out resistance in adding up you voltages.
And where is the resistance?
Your voltages should add like vectors.

The square wave drive complicates things above the simplicity of a sine wave drive. You can rough the answer by assuming an equivalent sine wave at 711 Hertz and and 10 VAC RMS.
 
  • #3
You can't get resonance with just two of the components like that.

The capacitor will resonate with the two inductors in series but not at 711 Hz. (more like 411 Hz). The circuit inductance is 15 H.

The whole loop, including the output impedance of the function generator, must be considered.

There will be some spurious effects due to the square wave and its harmonics, but consider it as a sinewave first to get the main effects.
 

Related to Series LC circuit and voltage magnification?

1. What is a Series LC circuit?

A Series LC circuit is a type of electrical circuit that contains a combination of a capacitor and an inductor connected in series. It has a resonant frequency at which the current and voltage in the circuit oscillate at maximum amplitude.

2. How does a Series LC circuit work?

In a Series LC circuit, the capacitor stores electrical energy in the form of an electric field, while the inductor stores energy in the form of a magnetic field. The two components interact with each other, causing the circuit to resonate at a specific frequency.

3. What is voltage magnification in a Series LC circuit?

Voltage magnification, also known as voltage amplification, is the phenomenon where the voltage across the capacitor in a Series LC circuit reaches a peak value that is greater than the applied voltage. This occurs at the resonant frequency of the circuit.

4. How is voltage magnification calculated in a Series LC circuit?

Voltage magnification in a Series LC circuit can be calculated using the formula Vc/Vin = √(1 + (XL - XC)^2), where Vc is the voltage across the capacitor, Vin is the applied voltage, XL is the inductive reactance, and XC is the capacitive reactance.

5. What are some practical applications of Series LC circuits?

Series LC circuits are commonly used in radio frequency (RF) systems, such as radio and television receivers, to select a specific frequency for tuning. They are also used in electronic filters, oscillators, and impedance matching circuits.

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