# Is this value fine for blocking capacitor?

Discussion in 'General Electronics Chat' started by Gordon Freeman, Sep 9, 2016.

1. ### Gordon Freeman Thread Starter New Member

Sep 6, 2016
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Im designing CE amplifier and I calculated the coupling capacitor C1 using the cutoff frequency equation and it turns out I need 0,2mcF with 2221ohm input impedance and 300Hz frequency. Is this value fine? I mean,

2. ### GopherT AAC Fanatic!

Nov 23, 2012
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4,019
How did it work on the breadboard? Only 5 parts - it should only take a few minutes.

Or, how did it work in the simulator? LTSpice, TI-TINA can simulate and show the frequency response.

The simulators are free from Linear Technologies and Texas Instruments.

Last edited: Sep 9, 2016
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3. ### AlbertHall Well-Known Member

Jun 4, 2014
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I don't understand your value "0,2mcF"
If your lowest frequency of interest is 300Hz then you should generally calculate the capacitor value to give the -3dB at 1/0th of that frequency - 30Hz - which for 2221Ω I make 2.39uF

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4. ### Gordon Freeman Thread Starter New Member

Sep 6, 2016
18
1
Hmm, didn't know about those simulators. I will try them, thanks!
I haven't yet tested the circuit, I meant in my question if I should trust the values I receive from calculating the capacitance this way, because I know this is the way (C=1/2пf*Zin), and yet as a beginner I have doubts.

5. ### Gordon Freeman Thread Starter New Member

Sep 6, 2016
18
1
Ahh, correct!
Oh and 1/0th means 1/10 right?

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6. ### AlbertHall Well-Known Member

Jun 4, 2014
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Sorry, yes 1/10

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Sep 6, 2016
18
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Thank you!