oscillator -Why&When do we need it ?

[smnyoed]

Hello my friends
I have a korg pa3x device.
It has a sampler, so I can load samples to the keyborad.
my questions:
oscillator use just for Electric sounds ? Or can I take an acoustic clarinet sample and add oscillators ?
If I can, what is the purpose to add oscillators for lets say a simple legato clarinet ?
Can I design the sound,so from a simple static clarinet sound it will be more reallistic ?
THANK YOU

[thecontrolcentre]

Do you mean LFO? You would use it to affect the modulation of the sound its applied to.