2014年6月11日星期三

Frequency response and passive filters

Objective: find the resonant frequency,then calculate the quality factor and bandwidth

Procedure:

Build the following circuit and record the value of the voltage in the capacitor at increasing frequencies
R= 1K
C= 1micro Farad

This will work as a passive filter. More specifically low pass filter

And also record the voltage in a high pass filter

This is our data and the graphs of a low pass filter and high pass filter

We observe how the function is decreasing. The voltage in the circuit is not equal to the V in because of that factor of 1/sqrt(2) that we get from our Vrms.

Vo/Vin is the gain in our circuit how on the lowpass the gain decreases when the frequency goes up and in the highpass filter the gain goes up as we increase the frequency.

Conclusion:
we learned how frequency-dependent circuits may be modified to obtain measurements of bandwidth.

Series resonance

Objective: find at which frequency will the circuit have the highest value for current in a RLC circuit and understand what is the quality factor, resonance frequency, and also bandwidth.

Procedure:

Build the following circuit and change the frequency and find the peak value for current

So our readings tell us the following

And then we can proceed to find the bandwidth, the quality factor and the resonance frequency

And now we change the values of the resistor and capacitor and we get this values for the experimental frequency and the rms current

So we proceed with calculations

Observations:

This lab demonstrated how certain frequencies with certain circuit elements can allow voltage through specific frequencies, and block all others. This is particularly useful if you are trying to broadcast/receive a signal at a specific frequency. Our largest margin of error was around 4%, which is indeed supah hawt and secksy.