Physically / intuitivelly what is a zero?

[diarmuid]

So I intuitively / physically understand a pole. Its a cap (parasitic or not), the charging /discharging of it drains the circuit gain and incurs phase shifts in the
circuit frequency response.

What is a zero then? I know its the oppositve of a pole (adds 20dB/dec, etc.) but physically - what is a zero?

Ive seen in a PLL, a zero is added to the LF by including a resistor. I know in op-amps, the RHP zero is moved to the LHP with a nulling resistor.

Therefore - physcially is a resistor a zero? If so, where does the frequency dependance of it come into play? i.e. a LHP zero with same frequency as a pole
cancels out the pole, etc.

Any advice much appreciated!

Thanks,

Diarmuid

 

[Dominik Przyborowski]

Zero is sthing like short between input and output.

 

[LvW]

So I intuitively / physically understand a pole. Its a cap (parasitic or not),
..............
Therefore - physcially is a resistor a zero?

Two simple answers:
No - a capacitor is a capacitor (and not a pole)
No - a resistor is a resistor (and not a zero).