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The Summing Amplifier In this part of the op-amp series, we’re going to build and test summing amplifiers . A summing amplifier combines multiple input signals into one output , making it one of the most useful and flexible op-amp building blocks. In this post we will: Build two types of summing amplifier Measure real voltages on the bench Match the math directly to what we measure Highlight practical limitations with single-supply op-amps What Is a Summing Amplifier? A summing amplifier is an op-amp circuit that adds multiple input signals together and produces a single output voltage. Key idea (very important): 👉 Summing amplifiers add currents , not voltages. 👉 The op-amp output converts the summed current back into a voltage. Each input voltage is converted into a current by a resistor. Those currents are summed at the op-amp input and converted back into a voltage at the output. There are two basic types of summing amplifiers: - Inverting Non-Inverting Type 1 — Inverti...

Non-Inverting Operational Amplifier In this post we will explore how a  non-inverting operational amplifier is used when you want to increase the size of a voltage signal without changing its polarity . If the input goes up, the output goes up. If the input goes down, the output goes down. This makes it one of the most common and useful op-amp configurations. In a non-inverting amplifier: The input signal is connected to the non-inverting (+) input The output is fed back to the inverting (–) input using two resistors The feedback resistors control how much the signal is amplified The key idea is simple: The op-amp adjusts its output so that the voltage on the – input matches the voltage on the + input. Gain Formula Assumed knowledge: This section builds on the rules and formulas introduced in Part 1 (Op-Amp Basics) and Part 2 (Inverting Amplifier) . We assume you are already familiar with negative feedback, ideal op-amp assumptions, and how resistor ratios set gain. The voltage...