Amplifier Circuits:  Differential

Difference amplifier uses digital potentiometers: 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 Drives highspeed ADC: EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Differential amp needs no power source: 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 ....

Fully Differential Input Voltage Amplifier : National Semiconductor Application Notes,28-Jun-1996