POT4 GAIN

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POT4 Gain Adjustment:

To change the instrumentation amp gain change the value of RA1 on the back side of the board. This component is a 1206 resistor and thus is somewhat larger than the others. The text "gain" is located near the RA1 label.

The instrumentation amp gain equation is : gain = 1 + 50k / RA1. At present the resistor value is 499 ohms for a IA gain of 101.2.

For a gain of 500x change RA1 to 100.2 ohms. Do this either by removing the existing RA1 or probably more easily stacking a 2nd RA1 on top of the existing RA1. The gain of 500 can be had with a 499 in parallel with 125 ohms.