Author Topic: calculate low pass  (Read 1108 times)

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Offline MepakosTopic starter

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calculate low pass
« on: September 11, 2019, 08:43:59 am »
Can u help me pls? Dont know if i am right or wrong.
 

Online ledtester

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Re: calculate low pass
« Reply #1 on: September 11, 2019, 09:03:42 am »
Um, your first mistake is here:

832167-0

« Last Edit: September 11, 2019, 09:06:43 am by ledtester »
 

Online ledtester

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Re: calculate low pass
« Reply #2 on: September 11, 2019, 09:29:41 am »
Another thing you have to be more careful about are the signs on your exponents:

832179-0

It should be 10^-6. This doesn't cause a problem since you make the same mistake later on and the two cancel each other out.

« Last Edit: September 11, 2019, 09:32:06 am by ledtester »
 

Offline GerryR

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Re: calculate low pass
« Reply #3 on: September 11, 2019, 12:00:32 pm »
You don't need to consider the source impedance (50  \$\Omega\$) in your calculation.  You handle the lo-pass as a regular voltage-divider network to find the "pole."  Try looking up Bode Plots to find how to find your poles and zeroes and phase for different networks.
Still learning; good judgment comes from experience, which comes from bad judgment!!
 

Online ledtester

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Re: calculate low pass
« Reply #4 on: September 11, 2019, 12:20:52 pm »
Try looking up Bode Plots to find how to find your poles and zeroes and phase for different networks.

Like this:

http://sim.okawa-denshi.jp/en/CRlowkeisan.htm
 

Offline MepakosTopic starter

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Re: calculate low pass
« Reply #5 on: September 16, 2019, 08:10:51 am »
Is this good?
 

Offline GerryR

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Re: calculate low pass
« Reply #6 on: September 16, 2019, 01:53:32 pm »
Figure out the impedance of the capacitor at 480 KHz, then use that in your voltage-divider formula to find the output voltage at that frequency [(Zc / R+Zc) * Ve]
Still learning; good judgment comes from experience, which comes from bad judgment!!
 

Offline avogadro

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Re: calculate low pass
« Reply #7 on: September 16, 2019, 10:11:02 pm »
Zc = 1/(2*pi*f*C) = 1/(2*pi*480E3*3.3E-9) = 100.5 ohm

UA = U0*(Zc)/(Zc+Ri+1Kohm) = 1*(100.5)/(100.5+50+1000) = 0.0874V
 


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