The Inverting Summing Amplifier #
A summing amplifier adds multiple input signals, each weighted by its own gain:
$$V_o = -\left(\frac{R_f}{R_1} V_1 + \frac{R_f}{R_2} V_2 + \cdots + \frac{R_f}{R_n} V_n\right)$$If all resistors are equal (\(R_f = R\)): \(V_o = -(V_1 + V_2 + \cdots + V_n)\)
Example #
\(V_1 = 2V, V_2 = 3V, R_1 = R_2 = R_f = 10k\Omega\) → \(V_o = -(2+3) = -5V\)
Applications #
Audio mixers, DACs (digital-to-analog converters), control systems.
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