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.

Register Log in

capacitor to suppress radio frequency signal

Status
Not open for further replies.
L

luckyvictor

Member level 4
Joined
Dec 1, 2009
Messages
78
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,903
Hi

I have attached a picture of a part of a circuit, with which I dont understand how C210 suppresses radio frequency, because it is connecting between positive and negative terminal of channel 1.

13_1293493487.jpg


Thanks in advance
 

C206/C207 help to reduce common mode interference but C210 will help to reduce differential interference i.e. interference which generates a signal between the positive and negative electrode terminals. I assume the important measurement is between the electrodes, not from the electrodes to ground. C210 will be low impedance at RF so will reduce the interference in combination with the electrode series resistors.

Keith
 

First of all thank you for your reply, however how does it help to reduce the interference? my confusion is, why don' we have two identical capacitor, with each of them connect between either positive or negative terminal and the ground?
 

There are already two identical capacitors to ground C206 & C207. They will only affect noise on each individual terminal. Noise between the two terminals needs a capacitor between the two terminals.

Keith.
 
I see, thank you so much for your clear explanation (and patience).

If you don mind, could you please also take a look of my second question?
 

The C210 capacitor may be fairly ineffective at lower
to mid frequencies, after all the series capacitance of
the C206/C207 pair is still 5X larger. However the larger
the capacitor, generally the lower its self-resonant
frequency and the point where it quits doing its job so
well. Perhaps the C210, 10pF is more effective than
the C206/C207 path at the very high end. That, or a
simple "mobetta" design philosophy at work.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top