AC Voltage output across Resistor

In summary, the task is to plot the amplitude of the AC voltage across a resistor in a circuit as a function of the angular frequency of the AC source. The complex impedance across the resistor is R and does not depend on the angular frequency, but the current and L-C impedances do vary with frequency. Therefore, the voltage across the resistor should also vary as it is in series with the L-C combination. To complete the task, one needs to find the total impedance of the parallel combination of L & C, which is a function of the angular frequency, and then take into account the series connection with R.
  • #1
tomeatworld
51
0

Homework Statement


For the circuit below (attached) plot the amplitude of AC voltage across resistor as a function of the angular frequency of the ac source.


Homework Equations


ZR = R

The Attempt at a Solution


I'm not really sure about any of this. Across the resistor, the complex impredence is just R and so has no dependence on the angular frequency, but just plotting a stright line with amplitude IR can't be worth 5 marks (which is the marks for this question). Can someone explain this to me?
 

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  • #2
The current I varies with frequency.
 
  • #3
the L & C impedances vary with frequency.
So, the voltage across the resistor should also vary as it is in series with the L-C combination.

Find out the total impedance of the parallel combination of L & C (which is a function of w).
Now R is in series with this combo-impedance.
 

1. What is AC voltage output across a resistor?

AC (alternating current) voltage output across a resistor is the measurement of the electrical potential difference across a resistor when an alternating current flows through it.

2. How is AC voltage output across a resistor calculated?

The AC voltage output across a resistor can be calculated using Ohm's Law: V=IR, where V is the voltage, I is the current, and R is the resistance. In an AC circuit, the voltage and current are constantly changing, so the calculation must take into account the peak values of voltage and current.

3. What is the relationship between AC voltage output and resistance?

The relationship between AC voltage output and resistance is inverse. This means that as the resistance increases, the voltage output decreases and vice versa. This relationship is described by Ohm's Law (V=IR).

4. How does the frequency of the AC current affect the voltage output across a resistor?

The frequency of the AC current does not directly affect the voltage output across a resistor. However, it can indirectly impact the voltage output by altering the current flow through the resistor. This is because the resistance of a resistor can vary with frequency due to factors such as capacitance and inductance.

5. Can AC voltage output across a resistor change over time?

Yes, AC voltage output across a resistor can change over time. This is because AC current alternates between positive and negative values, causing the voltage output across a resistor to also alternate. In addition, external factors such as changes in temperature or the resistance of the resistor itself can also cause the voltage output to change over time.

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