Calculate complex summing circuits accurately today.
A non-inverting summing amplifier is an advanced operational amplifier configuration that combines multiple input voltage signals together while providing a positive gain stage without phase inversion. Unlike standard inverting summers which mix signals at the virtual ground node, the non-inverting summing topology feeds input signals through a resistive network directly into the non-inverting input terminal of the operational amplifier. This approach offers extremely high input impedance, making it ideal for interfacing with delicate sensors, audio mixing consoles, and analog computing systems where loading effects must be completely avoided.
The mathematical evaluation involves two primary stages: determining the weighted average voltage at the non-inverting terminal ($V^+$) and scaling it using the closed-loop non-inverting gain ($A_v$).
1. Non-Inverting Terminal Voltage:
$$V^+ = \frac{\frac{V_1}{R_1} + \frac{V_2}{R_2} + \frac{V_3}{R_3}}{\frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}}$$
2. Closed-Loop Gain:
$$A_v = 1 + \frac{R_f}{R_g}$$
3. Final Output Voltage:
$$V_{out} = V^+ \times A_v$$
Using this application is straightforward. Enter your individual channel input voltages into the first column. Next, specify your input resistor values and select the correct resistance scale unit in the second column. Finally, define your feedback resistor, ground gain resistor, and op-amp power supply rails in the third column. Click the calculation button to instantly view precise output voltages and saturation warnings.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.