Filtraphor

Filtraphor is a hands-on signal lab for learning analog filters. Build RC, LC, and Butterworth topologies, drive them with classic stimuli, and watch time-domain ringing and frequency response update together.
SIGNAL LAB
• First- and second-order RC low-pass and high-pass
• LC low-pass, high-pass, and band-pass
• Butterworth 2nd and 4th order (maximally flat magnitude)
• Adjust cutoff / center frequency, damping ζ, and band-pass bandwidth
• Excite with sine, square, pulse, triangle, or chirp sweep
SEE TIME AND FREQUENCY TOGETHER
• Waveform view for edge rounding, overshoot, and ringing
• Bode magnitude and phase from the same settings
• Cutoff markers and readout chips for phase lag and key metrics
• Capture windows sized for educational insight, not lab certification
COMPARE AND KEEP
• Side-by-side topology comparison on shared stimuli
• Local Archive to save and reopen experiments on device
• Field Guide articles on poles, damping, Butterworth intent, LC resonance, and phase
BUILT FOR LEARNING
Filtraphor is a numerical teaching tool. It synthesizes signals on device and does not connect to instruments or hardware. Preferences and experiments stay on your iPhone—no account and no analytics in this build.
Whether you are brushing up on −20 dB/decade slopes, ζ and Q, or Butterworth flatness, Filtraphor turns filter theory into something you can dial, see, and save.