Low Frequency oscillators are used to create regular, complex, or even random slowly changing control voltages to change synthesizer filter, oscillator and parameters. The methods used can be oscillators, shape editors and sample/hold.
Creating an LFO using the standard oscillator
How to make a delayed LFO
Third Party TD LFOs
Complex LFOs
Adding an LFO to a synthesizer
ADSR generator
A looping envelope generator
ED Shape Editor envelope generator
Sample hold