Single-Supply Difference Amplifier

The circuit is a difference amplifier using a single power supply. The input signals are unipolar sine waves (with an offset at half the power supply voltage). The circuit amplifies the difference between the two input signals by 2 (voltage gain = 2) and centers the result in the middle of the power supply voltage. The T attenuator at the noninverting input combines the signal and the power supply voltage with attenuation factors of 2/3 and 1/6 respectively. Without Rg only complementary attenuation factors, Rniv/(Rniv + Rvcc) and Rvcc/(Rniv + Rvcc), are obtainable. The input signals may have nonzero phase angles, this should be taken into account when checking the results. The phase difference can also result to saturated output even when the difference in amplitude is not greater than 2.5 V. In the saved circuit the signal at the inverting input has a phase angle of 90°. It's OK to use power supply voltages other than 5 V.