Acestuff
Newbie level 3
I am having a great deal of problems trying to work out the corner frequencies of 2 filters (one high pass, one low pass) which are part of a circuit I need to analyze.
The problem is that these filters have 2 resistors in them; all the information on the internet refers to 1 resistor in the filter! I am using this equation:
With the low pass filter:
Intuitively I know that (excuse the poor terminology!) if I used the equation with just the 10k resistor, the cut-off frequency should be lower than calculated with the equation I stated because there is voltage "leaking" through the 100k resistor.
The use of Thevenin's theorem to solve this problem comes to mind. I'd then get a 9.09...kohm resistor in series with the output which would fit into the equation.
However, this means the denominator of the f_c equation is lower thus a higher frequency will be calculated. This goes against my intuition that the frequency should be lower!
I don't know where I'm going wrong so any help you can give would be amazing! The amount of time I've wasted thinking about these problems...
Low Pass:
High Pass:
(Input from top, output to right)
The problem is that these filters have 2 resistors in them; all the information on the internet refers to 1 resistor in the filter! I am using this equation:
Code:
f_c = 1/(2πRC)
With the low pass filter:
Intuitively I know that (excuse the poor terminology!) if I used the equation with just the 10k resistor, the cut-off frequency should be lower than calculated with the equation I stated because there is voltage "leaking" through the 100k resistor.
The use of Thevenin's theorem to solve this problem comes to mind. I'd then get a 9.09...kohm resistor in series with the output which would fit into the equation.
However, this means the denominator of the f_c equation is lower thus a higher frequency will be calculated. This goes against my intuition that the frequency should be lower!
I don't know where I'm going wrong so any help you can give would be amazing! The amount of time I've wasted thinking about these problems...
Low Pass:
High Pass:
(Input from top, output to right)