This bit from Bitwig's Modular Concepts series covers how to patch an LFO into pitch to create two distinct musical effects: a trill and a vibrato. Starting with a pulse wave LFO, the host shows how switching from an envelope to an LFO produces a stepped trill that jumps between pitches, with an attenuator controlling the interval size.
The more instructive moment comes with vibrato. A standard sine wave LFO seems like the obvious choice, but a unipolar signal pulls the pitch upward from the played note rather than wobbling around it, producing a glissando effect instead. The fix is switching the LFO to bipolar mode, so the modulation oscillates symmetrically above and below the target pitch.
This unipolar-versus-bipolar distinction is one of the most common sources of detuning in synth patches. Any time a modulation source is meant to express variation around a center value rather than offset from zero, bipolar is the right choice.