The value of the feedback resistor, Rf, and input resistors determine the gain of the summing amplifier. V out = -R f (V 1/R 1 + V 2/R 2 + … + V n/R n)Īssuming that each of the input resistors has the same value, the equation can be simplified into. V out/R f = V 1/R 1 + V 2/R 2 + … + V n/R n Therefore, the relationship between the current flowing through the resistors can be formed with: First, the no current flows into the input of an op-amp, and second, the voltage difference between both input terminals is zero.īased on the above golden rules, the inverting terminal becomes a virtual earth summing point as the non-inverting terminal is connected to 0V earth ground. It is important to remember two basic rules of op-amp when understanding how a summing amplifier functions. The summing amplifier merely has more input resistors connected in parallel to the inverting terminal of the op-amp. If you’re familiar with an inverting amplifier, you’ll find that the summing amplifier shares a similar structure. Usually, a summing amplifier is in fact an inverting amplifier, which means the output voltage has a negative value when measured to ground. Based on its unique properties, an op-amp can be configured for various functions, including a summing amplifier.Īlso known as the adder, the summing amplifier produces a voltage output that is equivalent to an amplified sum of two or more input voltages. An ideal op-amp has characteristics like infinite input impedance, infinite gain, and zero output impedance. What is a Summing AmplifierĪ summing amplifier is, in fact, an operational amplifier (op-amp) configured in a specific manner. You ought to understand the in’s and out’s of the summing amplifier before using one in design. It proves to be a useful component in mixing up analog signals. In electronics, the summing amplifier proves to be as useful as the calculator or more, in adding up the value of currents from various inputs. Instead, I relied on one of man’s greatest inventions, the calculator, as I struggled through one assignment to another during my university days.

Mental arithmetic was never my forte, despite being in the engineering profession. What is 5,592 + 9,861? And that’s how my mind goes blank. The summing amplifier is configured from an op-amp. Explore how summing amplifiers are used in practical applications.

Bidule as summing amp