# Problem understanding the operations of capacitor

So far I've learnt about some different types of capacitor arrangements , such as coupling , decoupling , bypass , filtering , and smoothing capacitor. Decoupling and bypass capacitors are the same and filtering and smoothing capacitors are the same(Correct me if I am wrong).

In this diagram of a voltage-divider bias CE amplifier above , The capacitor C1 is used as a coupling capacitor as it is connected in series , and blocks DC signals and passes (couples) only the pure AC signal from the source to the circuitry for amplification. And , the capacitor C2 is a bypass capacitor connected in parallel as a shunt , therefore the AC component will pass through C2 to ground and will not be superimposed on the input as feedback , while the DC will go through the resistance Re ; because , We know that the capacitor reactance: $$Xc = 1/ 2\pi f C$$ Where F is the frequency of the signal and C is the capacitance. So, If the frequency increases (ac signals) the capacitive resistance decreases , and signal uninterruptedly flows from one section to another , i.e. is coupled , while the dc signal with zero frequency is blocked by infinite resistance. Same thing happens with the bypass capacitor C2

Here comes my first question , 1. Explain me why the increase of frequency decreases the reactance of capacitor? Not by using the formula written above , but using practical theory of flow of electrons , charging discharging etc.

My second question , 2.Is the capacitor used in full wave or bridge rectifier , i.e. the filtering capacitor in coupling arrangement or decoupling arrangement or none?

3. What type of capacitor arrangement is it that is used on the input of a negative feedback amplifier?

• "1. Explain me why the increase of frequency decreases the reactance of capacitor?" If you can, get your hands on a function generator, and observe the voltage across a capacitor on an oscilloscope. You will understand intuitively. – Giulio Muscarello Jun 14 '15 at 15:03