Interactive AC Intuition Builder

3D Phasor & Signal Visualizer

Watch rotating vectors become sine waves. Compare input and output phasors, reveal the phase gap directly, and flip the RC low-pass model on to see why higher frequency signals shrink and lag.

Vin vs VoutRC Low-Pass ModePhase Angle + Waveform Sync

3D View

Rotating Phasors

VinVoutPhase Arc

Input

1.00

Reference amplitude

Output

0.650

65.0% of Vin

Phase Shift

-49.5 deg

1.143 ms lag

Time Domain

Synced Waveform Projection

Blue = VinOrange = Vout

Controls

Tune the Filter

The scene now starts paused in a readable state. Press play when you want to watch the phasors rotate.

Frequency

Higher frequency means faster rotation and more low-pass attenuation.

120.2 Hz

Resistance

Resistance and capacitance together set the cutoff frequency.

4.68 kOhm

Capacitance

Capacitor reactance drops as frequency rises, pulling Vout down.

331.13 nF

RC low-pass modeToggle between ideal unity output and filtered output.Show waveformKeep the time-domain trace visible under the 3D scene.Show phase angleReveal the angle arc between Vin and Vout phasors.

Playback speed

Scales the visual spin rate without changing filter math.

1.0x

Paused on load

Cutoff

102.8 Hz

fc = 1 / (2piRC)

Capacitive Reactance

4.00 kOhm

Xc = 1 / (2pifC)

What to Notice

When 120.2 Hz is below cutoff, the orange vector almost matches the blue one. As it moves above cutoff, the capacitor looks less like an open circuit and more like a path to ground, so Vout loses magnitude and rotates backward.

Why does output lag?

The capacitor needs time to charge and discharge, so the output phasor rotates behind the input phasor by -49.5 deg.

What is impedance doing?

At this setting, Xc is 4.00 kOhm. Comparing Xc with R = 4.68 kOhm tells you how strongly the output is divided down.

How to read the picture

Vector length is amplitude. Vector angle is phase. The waveform is just the rotating tip projected onto one axis over time.