Posts

Op-Amp Series – Part 5: The Differential Amplifier

-
Image
  The Differential Amplifier A differential amplifier is an operational amplifier circuit that amplifies the difference between two input voltages . Instead of measuring a signal relative to ground, it measures how much one signal differs from another . This makes differential amplifiers incredibly useful for: Rejecting noise Comparing signals Sensor interfaces Audio and measurement circuits In simple mathematical terms: Output = (Input 1 – Input 2) × Gain In the real world, signals are often noisy. Long wires, motors, power supplies, and digital circuits can all introduce interference. A differential amplifier helps by: Amplifying only the difference between inputs Rejecting signals that appear equally on both inputs (called common-mode signals ) The Basic Differential Amplifier Circuit Differential Amplifier Circuit A classic differential amplifier uses four resistors and one op-amp. For proper operation: Resistor ratios must match This ensures accurate subtract...
Post a Comment
Read more

Op-Amp Series – Part 4: The Summing Amplifier

-
Image
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...
Post a Comment
Read more

Op-Amp Series – Part 3: Non-Inverting Operational Amplifier

-
Image
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...
Post a Comment
Read more

Op-Amp Series – Part 2: Inverting Operational Amplifier

-
Image
Inverting Operational Amplifier In this post we explore another important op-amp configuration: the inverting amplifier. Before building the circuit, we’ll look at the theory, understand the equations, and explain every term clearly. This circuit is perfect for learning how op-amps control current, how virtual ground works, and how gain is set using just two resistors. Inverting Op-Amp Theory of the Inverting Amplifier The inverting amplifier does two main things: It inverts the input signal. It scales that signal by a gain set by two resistors. The key concept is virtual ground . The non-inverting input (+) is connected to ground (0V) The op-amp adjusts its output so the inverting input (–) also sits at 0V, even though it isn't physically connected to it. Because the op-amp inputs draw almost no current: All current entering through the input resistor Rin must flow through the feedback resistor Rf. This gives us a simple and powerful relationship that leads to the ga...
Post a Comment
Read more