Difference amplifier uses digital potentiometers:
05/30/2002 EDN - Design Ideas / You sometimes need to measure a
small signal in the presence of a large common-mode signal.
Traditional instrumentation amplifiers that use two or three op
amps in their internal structure find common use in these
applications. The circuit in Figure 1 presents an alternative
approach that is useful when low cost and low drift are
important, but when you don't need high precision..
Differential amp needs no power source: 05/02/2002 EDN -
Design Ideas / A true-differential, power-source-free,
high-input-impedance amplifier with bipolar output would present
distinct advantages in remote devices. Such an amplifier, with
its bipolar output, would be a better choice than a unipolar, 4-
to 20-mA device. It would also improve on common-mode
performance. In Figure 1, a Maxim MAX319 analog switch, IC2,
feeds the power from the coaxial signal cable to ....