An
op-amp integrator is a circuit that performs the mathematical operation of integration. In simple terms, it converts a changing voltage (input signal) into a proportional output voltage that is the
integral of the input signal over time.
How it works:
- Basic Components:
- An
operational amplifier (op-amp), which is the heart of the circuit.
- A
resistor (R) connected to the input voltage.
- A
capacitor (C) connected to the feedback loop from the output to the inverting input.
- Principle: The input voltage is applied through the resistor, and the capacitor in the feedback loop stores charge as the input voltage changes. The output voltage is a result of the integration of the input signal. This means that as the input signal changes over time, the output will "accumulate" or integrate that change.
- Output Equation:
- The output voltage \(V_{out}(t)\) is related to the input voltage \(V_{in}(t)\) by the equation:
\[
V_{out}(t) = - \frac{1}{RC} \int V_{in}(t) \, dt
\]
- Here, \(R\) is the resistance, \(C\) is the capacitance, and the negative sign indicates a phase inversion (this is typical in an inverting configuration for the op-amp).
- What does integration mean in this context?:
- In the case of a voltage signal, the integrator takes the "area under the curve" of the input voltage. If you think of the input signal as a graph of voltage vs. time, the output voltage will change depending on how much the input voltage has been over time.
Key Points:
- Input signal: A voltage that changes over time (e.g., a sine wave, square wave, etc.).
- Output signal: A voltage that represents the integral (the "sum" or accumulated value) of the input over time.
- Phase inversion: The output is inverted (opposite polarity) compared to the input signal.
- Usage: Op-amp integrators are often used in signal processing, analog computers, waveform generation, and other applications where integration is required, like converting time-domain signals to frequency-domain information.
Example:
If you apply a constant voltage to the integrator, the output will steadily increase (or decrease) over time, creating a ramp signal. If the input is a sine wave, the output will be a cosine wave.
In short, the op-amp integrator "remembers" how the input changes and outputs a voltage that reflects that accumulated change over time.