circuit implementation doubt

Status
Not open for further replies.
M

Mridu

Newbie level 5
Joined
Jun 16, 2011
Messages
10
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Visit site
Activity points
1,354
Hi all,

I have designed a circuit for recording normal breath signal.........it has an instrumentation amplifier(ina101hp)and a low pass filter..........the Instrumentation amplifier INA101HP has been designed with a gain of 5.......Low pass filter also has a gain of 19..........i am recording breath signal using piezo disc............the problem with my circuit is i do not get the output from low pass filter and also the IA output is also not stable.......the output from instrumentation amplifier (when it is present) is about 1.47Hz............can this be given to a PC soundcard for recording?

regards
mridula
 

I am afraid, without a circuit diagram nobody can help you.
 

hi there........this is my circuit diagram............pls chk it and find the fault
 

Attachments

  • circuit.bmp
    1.7 MB · Views: 78

A popular fault in applying instrumentation amplifiers is to forget the required input bias. If this is your complete circuit, welcome to the club.

I also guess, that your low-pass has a cut-off frequenc in the x*10 Hz range and uses 18.2k rather than 18.2 ohm resistors.
 
Reactions: LvW

    LvW

    Points: 2
    Helpful Answer Positive Rating
yes it is true...........mine is 18K resistors..........


 

hi there...............i tried to reduce the offset voltage with trim pot but it was not at all useful.........and also DC WAS 29.0v without any input.........any reasons?
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…