Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Question about functioning of high pass filter

Status
Not open for further replies.

davors

Newbie level 4
Joined
Oct 16, 2004
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
61
hmmm... let me think...

hmmm...
as what i know. for a LOW PASS filter, when the capacitor is an open cct, no current flows via any of the elements since they rall in series with the capacitor... the current through the resistances is zero, the voltage across them is zero... so Vi = Vo right? when the capacitor is shorted then, frequency is arbitrarily big, so the Vo = 0...

for high pass case... is it just the reverse thing? hmmm... any idea? :cry:
 

Re: hmmm... let me think...

For High pass put series C and shunt R
for Low pass put series R and shunt C
 

Re: hmmm... let me think...

the current through a capacitor = C dv/dt which when solved for a sinusoidal wave Magnitude(V) = Magnitude(i)/ (2*pi*f*C) thus for very low frequencies applying a voltage across the capacitor yields very small current which makes the capacitor acts as a very high impedance (or open circuit at d.c). Similarly for very high frequencies applying a voltage across the capacitor yields very high current which makes the capacitor act as a short circuit at high frequencies.

thus for high pass filter at low frequencies the capacitor isolates the input voltage and the resistance has no current in it thus producing an output voltage =0

at high requencies the capacitor acts as a short ciruit connecting the input and the output voltages

----| |--------
|
|
\
/
\
/
|
--------------
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top