Z-Foil vs Thin Film Resistors with Intersil Instrumentation Amplifier (Demo Video)
Can precision resistors affect the price of gold? Precision amplifiers depend upon the ratio of input and feedback resistors to set the circuit accuracy and common mode rejection ratio. Changes in the ratio of the resistors constitute a direct unattenuated error at the output. TCR mismatch is the first and most direct cause of ratio change. This demo uses a load cell with an Intersil ISL28617 low-noise precision instrument amplifier to weigh gold at 25⁰C and 60⁰C. With thin film resistors around the amplifier there is a significant and costly loss as a result of TCR mismatch, while the Z-Foil chip resistors showed no change nor loss.