# Finding cutoff frequency with Short/Open Circuit Time Constant

Discussion in 'Electronics Homework Help' started by BlackMelon, Apr 28, 2015.

1. ### BlackMelon

188
5
Aug 7, 2012
As in the attached circuit, you should look at the file "OTC.jpg" first because the problem statement and the circuit are in there. I solved for cutoff frequencies, and I got a lower cut off frequency greater than a higher cut off frequency.
Is there anything wrong?

Thanks

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2. ### Laplace

1,252
184
Apr 4, 2010
I tried making a Bode plot of the circuit the old-fashioned way. Just what points on that graph do you think you are calculating?

3. ### BlackMelon

188
5
Aug 7, 2012
I'm finding both lower and upper corner frequencies by using open circuit time constant (for the upper one) and short circuit time constant (for the lower one) technique. I wonder why I've got a lower corner freq. greater than the upper

PS:Thanks for the Bode plot. I usually use MATLAB to do so. What kind of program do you love to use?

4. ### Laplace

1,252
184
Apr 4, 2010
The symbolic algebra engine I use is MathCad 15 running in a Windows 7 virtual machine on my CentOS 7 Linux computer. Have just installed the Linux version of Maple 2015 and am trying to learn how to use that.

5. ### LvW

604
146
Apr 12, 2014
Can you tell us upon which rule your method (open circuit/short circuit) is based on?