Hi.
I have some questions about controlling the frequency gain of an op amp. In figure 1, capacitor C1 is setting a high pass filter at 329Hz.
Question 1. Would the low frequencies from the output of the op amp have phase shift like a passive high pass filter output? Or do they remain in phase?
It seems like they should remain in phase but I am still new to this stuff.
Now what I want to do is make a variable high pass filter. In figure 2, I added a pot to bypass C1 to ground. So when the pot is turn down all the way, the capacitor is bypassed and the low frequencies are all amplified. Turned up full, the low frequencies roll off at 329Hz.
I am not sure if this will work because I can't seem to find any info on what effect a resistor parallel with the capacitor to ground would have on the circuit.
Question 2. Will a resistor parallel with C1 to ground change the way the circuit works? Would the lows still roll off at 329Hz? Or would it change the over all gain of the op amp?
Any help would be appreciated.
Thanks
Scott
I have some questions about controlling the frequency gain of an op amp. In figure 1, capacitor C1 is setting a high pass filter at 329Hz.
Question 1. Would the low frequencies from the output of the op amp have phase shift like a passive high pass filter output? Or do they remain in phase?
It seems like they should remain in phase but I am still new to this stuff.
Now what I want to do is make a variable high pass filter. In figure 2, I added a pot to bypass C1 to ground. So when the pot is turn down all the way, the capacitor is bypassed and the low frequencies are all amplified. Turned up full, the low frequencies roll off at 329Hz.
I am not sure if this will work because I can't seem to find any info on what effect a resistor parallel with the capacitor to ground would have on the circuit.
Question 2. Will a resistor parallel with C1 to ground change the way the circuit works? Would the lows still roll off at 329Hz? Or would it change the over all gain of the op amp?
Any help would be appreciated.
Thanks
Scott
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