AC Filters & Resonance

Passive RC Integrator (Square-to-Triangle Wave) Simulator

Convert a square wave into a triangular ramp waveform when RC time constant exceeds half the signal period.

Speed
Compare the AC input wave (CH1) against the filtered capacitor voltage (CH2). Increase the AC frequency to see attenuation and approach -90° phase lag (switch Scope to XY Lissajous!).
● CH1: CH1
● CH2: CH2

Engineering Theory & Mathematical Model

Vout(t) ≈ (1 / RC) ∫ Vin(t) dt (for τ ≫ T/2)

When the time constant τ = RC is significantly larger than the half-period of an input square wave, capacitor voltage stays on the initial linear portion of its exponential curve, integrating constant positive/negative plateaus into clean upward and downward triangle ramps.

Interactive Lab Procedure

  1. Click VAC1 and change Waveform from "Sine" to "Square", and set Frequency to 350 Hz.
  2. Observe CH2 transform into a clean triangular waveform integrated from CH1!
  3. Lower frequency to 30 Hz to see full exponential saturation return.

Technical FAQ

What is the core governing formula for Passive RC Integrator (Square-to-Triangle Wave) Simulator?

Vout(t) ≈ (1 / RC) ∫ Vin(t) dt (for τ ≫ T/2) — When the time constant τ = RC is significantly larger than the half-period of an input square wave, capacitor voltage stays on the initial linear portion of its exponential curve, integrating constant positive/negative plateaus into clean upward and downward triangle ramps.

Can I modify component values and rewire this circuit live?

Yes! The schematic above runs a live MNA SPICE engine. Click any part to adjust parameters, add or delete wires and components, and click Share URL to save your custom topology.

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