Summing amplifier configuration (AQA A-Level Physics): Flashcards

Amplifies multiple input signals independently

Audio mixers

Virtual earth

$V_{\text{out}} = -R_f(\frac{V_1}{R_1} + \frac{V_2}{R_2} + ...)$

Output is inverted relative to inputs

Finds difference between two input signals

$V_{\text{out}} = (V_+ - V_-)\frac{R_f}{R_1}$

Noise cancellation

50 Hz mains interference

Often equal for equal weighting of signals