On 07/06/2013 01:04 PM, JAMES RIDOUT wrote:
> Hello all, Sorry to be a pain, But ive just built the two 741 opamp circuits,
> Ive been very carefull with construction, but in getting a lot of noise!, if I
> unplug the feed from the coil im getting the data value (in amaseis), jumping
> about 1000 points +&-.
> im using two 12v switch mode power supplies.
>   Im not great at electronics, but I know the basics.
> Im using a dataq 194.
>   Any help would be great!.
>      Thanks,   James

Hi James,

The 741 is not considered a low noise amplifier.  Take a look at the Linear Tech
LT1007, for example.

It would help determine if what you are seeing is expected if we knew:

  circuit diagram (do you have link?)
  brand / model of power supply (switch mode is often pretty noisy)

The Dataq 194 is only 10 bits (counts of -512 to +512) so not sure I understand
the +/- 1000 counts observed.  Maybe something from Amaseis (I don't use that)?


-- 
Bob Smither                                 bob@...........
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