Please check the circuit in the attachment and explain where the pointed node should be connected? What is that whole cylinder thing, my guess is that its just a lengthy connection.
Thanks

 

The "cylinder" is the shielding braid in the cable between the "patient", and the amplifier input.

Ken

 

The "cylinder" is the shielding braid in the cable between the "patient", and the amplifier input.

Ken

What exactly is a shielding braid?

 

http://en.wikipedia.org/wiki/Shielded_cable

http://www.aerovisions.com/pic/XeVision-cable-assy-cable.jpg

Though in "patient cables", and other shielded cables that require flexibility, the foil layer shield is not used, and the braided layer is made more dense.

Ken

 

You could use shielded microphone cable.

 

Ok but where do i connect the output from the amplifier???

 

Ok but where do i connect the output from the amplifier???

To the EKG monitor, of course.

 

To the EKG monitor, of course.

Sgt I meant the output from OPA2604 I have pointed it with red pointer in the circuit diagram

 

Connect it to the drain wire of the shield.

 

Sgt I meant the output from OPA2604 I have pointed it with red pointer in the circuit diagram

Ahh, OK.

The OPA2604 is a shield driver. It attempts to force the shield to be at the same voltage potential as Rg/2, the gain resistor of the INA118 instrumentation amplifier.

This minimizes the influence of outside voltage potentials. Ideally, the voltage potential on the shield will be the same as Rg/2, which will minimize any impact (distortion) on the signal input to the INA118.

 

Thanks to all
Cheers