Impedance!

Sounds kinda like Impudence!
I have an exciting announcement to make, that has nothing to do with class, but what would a blog be without boasting about personal issues?

I GOT INTO MIT!!! Yay!! Which is extra cool since I have no background in engineering, and still got into the best (or one of) Aerospace Engineering program in the Country!!  In case you didn't know I am deciding between MIT and Cornell, so if anyone has insider information on who's better feel free to leave a comment!

So back to impedance.... another word for resistance.  All instruments have inherent impedance, no matter how much money you throw at it., so we had an activity to try to measure the impedance of our oscilloscopes. (which apparently have a capacitor and resistor in parallel)
At 100Hz, I calculated a Thevinin resistance of 1MegaOhm in the oscilloscope.
At 10kHz, the resistance fell to 140k.  I was going to figure out a way to solve for R&C using these data points when I realized I could look back at the filter lab we did earlier.  I found the frequency (2.5kHz) at which the voltage recorded by the oscilloscope dropped to 0.7, the f3dB!  Which should equal 1/(2pi*RC). Using this, I solved for RC (6.3x10^-5) and plugged this into the equation for resistors in parallel [R1R2/(R1+R2)]=Rthevinin.  Simplified with a cap in it Rth = [R/(wCR +1)]  which would be R / (really really small number + 1) --> R.
So R ~ 1Megaohm and C ~ 63 pico Farads