Isolating harmonics with band-pass filter

[Fischer777]

If electric waveforms such as square waves, sawtooth waves, and triangle waves are really no more than sine waves with added harmonics, one could run such a wave through a bandpass filter (or several) and isolate one of the harmonics as a sine wave?

 

[yungman]

Yes! You need good and sharp BPF though. Also, it's all relative, it's all about how low you want to suppress the unwanted harmonics.