Calculator Input
Choose a circuit. Enter the values matching that circuit.
Example Data Table
| Circuit | Sample Inputs | Main Formula | Expected Result |
|---|---|---|---|
| Non-inverting amplifier | Vin = 0.2 V, R1 = 10 kΩ, Rf = 100 kΩ | Av = 1 + Rf/R1 | Gain = 11, Vout = 2.2 V |
| Inverting amplifier | Vin = 0.2 V, Rin = 10 kΩ, Rf = 100 kΩ | Av = -Rf/Rin | Gain = -10, Vout = -2 V |
| Comparator | Vin = 0.7 V, Vref = 0.5 V, rails = 5 V and 0 V | Vin greater than Vref | Output = high rail |
| Low-pass filter | R = 10 kΩ, C = 10 nF | fc = 1/(2πRC) | fc ≈ 1591.55 Hz |
Formula Used
Inverting amplifier: Av = -Rf / Rin. Output equals Av multiplied by Vin.
Non-inverting amplifier: Av = 1 + Rf / R1. Output equals Av multiplied by Vin.
Voltage follower: Av = 1. Output ideally follows the input voltage.
Differential amplifier: Vout = (R2 / R1) × (V2 - V1), using balanced ratios.
Summing amplifier: Vout = -Rf × (V1/R1 + V2/R2 + V3/R3).
Integrator: |Av| = 1 / (2πfRinC), for a sine wave estimate.
Differentiator: |Av| = 2πfRfC, for a sine wave estimate.
Active filters: fc = 1 / (2πRC). Magnitude depends on frequency ratio.
Comparator: Output switches high when Vin exceeds Vref. Otherwise it switches low.
How To Use This Calculator
- Select the operational amplifier circuit from the list.
- Enter input voltage values needed by that circuit.
- Enter resistor values in kilo-ohms.
- Enter capacitance in nano-farads for filter or timing circuits.
- Enter supply rails to check output clipping.
- Press the calculate button.
- Review the result shown above the form.
- Download the CSV or PDF report when needed.
Operational Amplifier Circuit Planning
An operational amplifier can solve many signal problems. It can invert a signal, raise its level, compare two voltages, or shape frequency response. This calculator helps you test those choices before wiring a circuit. It treats the op amp as ideal for most modes. That keeps the result clear and useful for quick design checks.
Why These Calculations Matter
Gain is the first value to review. In an inverting circuit, feedback and input resistors set a negative gain. In a non-inverting circuit, the same parts set a positive gain. The output voltage then depends on input voltage and supply rails. If the ideal output exceeds the rails, a real op amp clips. The calculator shows this condition so you can change gain or supply voltage early.
Frequency And Timing Checks
Filters, integrators, and differentiators need resistance, capacitance, and frequency. These values decide cutoff, gain magnitude, and phase behavior. A low-pass circuit keeps slower signals and reduces faster signals. A high-pass circuit does the opposite. Integrator output falls as frequency rises. Differentiator output rises as frequency rises. These checks are helpful when testing sensors, audio paths, and control loops.
Using Results In Design
The calculator also supports summing, differential, follower, and comparator work. A summing amplifier combines three inputs through separate resistors. A differential amplifier measures the difference between two input voltages. A follower buffers a signal without changing its ideal voltage. A comparator switches between supply rails when the input crosses a reference. These modes cover many lab and product tasks.
Practical Notes
Real devices have limits. Input bias current, slew rate, offset voltage, output drive, and bandwidth can change performance. Always compare the calculated result with the selected data sheet. Use the result as a design guide, not as a final guarantee. After choosing parts, test the circuit on a bench. Then export the report for records, assignments, or team review.
Good resistor scaling matters too. Very low values waste current and load previous stages. Very high values raise noise and bias errors. Choose capacitor values with tolerance in mind. Keep input signals inside the common mode range. Leave output headroom for peaks. These habits make the calculated design more reliable during real use daily.
FAQs
What is an operational amplifier calculator?
It estimates gain, output voltage, cutoff frequency, and comparator output for common op amp circuits. It helps review designs before building them.
Does this calculator include rail clipping?
Yes. It compares the ideal output with the entered supply rails. If the result exceeds the rails, it reports a limited output.
Which resistor unit should I enter?
Enter all resistor values in kilo-ohms. The calculator converts them internally for current, gain, and filter calculations.
Which capacitor unit should I enter?
Enter capacitance in nano-farads. This is used for filters, integrators, and differentiators.
Can it calculate active filter cutoff?
Yes. It calculates first-order low-pass and high-pass cutoff frequency using resistance and capacitance values.
Is the result exact for real op amps?
No. It uses ideal equations. Real parts have bandwidth, slew rate, offset, bias current, and output drive limits.
Can I use it for comparator circuits?
Yes. Enter Vin, Vref, and supply rails. The calculator reports whether the output goes high or low.
Why export CSV or PDF?
CSV is useful for spreadsheets. PDF is useful for reports, lab records, design notes, and project documentation.