Experiment 12: Frequency Response and Filters

Introduction:

     In electrical engineering, signal modification is a crucial component to many solutions to real world problems. In this experiment, we will be working with high pass and pow pass analog filters to form a deeper understanding on how frequencies are amplified or reduced. There will also be data and error analysis.

List of Materials

Capacitor box set to 0.1 micro Farad, 1000 Ω resistor, Frequency generator, DMM, leads.

First, we calculated the theoretical gain of the low pass filter frequency response for variable values of frequency. We then set up the circuit accordingly to this diagram.

Low Pass Filter Frequency Response Set up

Finally the circuit.

That Keyboard Doe

Here's our result

We move onto the next step in the experiment: High pass filter frequency response: simply measure across the resistor instead.

Actual results of the high pass frequency filter circuit

Finally, we use excel to graph our function., the input RMS voltage from the function generator was 5V. In order to calculate gain, we took the voltage obtained through the measurements and divided by 5V rms. The Y axis is the experiment's gain and the X axis is the frequency.

As we can see, the high pass frequency filter tops off at around 2000-3000 Hz, which is probably the natural frequency of the circuit.








For the low pass frequency filter, it is obviously shown in this graph that low frequencies around 10-100 hz aren't affected while the higher frequencies drop off.

NOTE: one observation we noted during the lab is that as the frequency increased, the Vin had to be slightly increased in order to maintain a steady Vrms. 

Conclusion

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 2.5%, which is indeed supah hawt and secksy.