# What exactly happens in a low and a high pass filter?

I know the mathematics and equations behind the circuitry and how they tell us that the resistor blocks high frequency ac signals and allows low frequency ac signals to pass through with undiminished amplitude. Similarly, a capacitor blocks low frequency ac signals and allows high frequency ac signals to pass through with undiminished amplitude.

But what is the physics behind this? Can anyone explain to me this phenomenon without using any mathematics?

I did not find a proper theoretical explanation for this anywhere.

• It is unclear what you want. You said you know the math and circuitry behind it, so the only thing left is to understand the physics behind how the components themselves operate, which is a Wikipedia page away... Apr 25 '17 at 16:49
• The mathematical derivation for it should be entirely based on the circuit, which is physics. If you understand how to get it with the math, just consider what you are actually doing.
– JMac
Apr 25 '17 at 16:51
• The resistor isn't blocking anything. Apr 25 '17 at 17:06
• @JonCuster, unless it has some parasitic inductance. Apr 25 '17 at 17:16
• @ThePhoton - having used a precision wire-round resistor as a 'precision' small value inductor before, I can agree to some extent... Apr 25 '17 at 17:36