Noise Reduction in Amplifier Circuit

[dermot]

Hi I have designed a differential amplifier circuit to act as a kind of a weighing scales, the Wheatstone bridge consists of 2 very sensitive strain gauges, since im amplifying such a small voltage my gain is required to be about 8,000 to get a reasonable measure. But as you are aware this causes problems for any noise present in the circuit as it will just swamp my signal and I wont get any readout, cud I have advice about the possibility of placing smoothing capacitors (size,type,location) and the possibility of using filters. I’ve included a schematic of my circuit model.

Thanks

[James Long]

Dermot,

I'll let John tackle the electrical part of the problem.

You didn't say what this amplifier will be connected to. If it is a microcontroller, it may be possible to filter with software. That is not the best route, but it may have to be part of the solution.

If this is a direct connection to some kind of display, I can see problems with this approach.

Also you didn't say how fast of a reaction time you needed (wanted). This will also play a part of the solution. Ths smoother you want the output, the slower the reaction time (typically).

Just my view on the situation,

James L

[dermot]

This circuit is only basically to prove that this method of implementing a weighing scales works. the output is simply connected to a voltmeter and this voltage output has a relationship to the corresponding weight applied to the strain gauge. Therefore the response time does not matter. It is not connected to any micro controller. Would a low pass filter remove the noise? Where should it be placed?