Why use LDR in an LFO circuit for delay? any subtitutions?

[stratprince]

why? are there any LFO circuits without using LDRs that i can add to my delay?

[R.G.]

There is a whole class of questions that seem logically like they should have simple answers, but don't. This is one of those.

It depends on the details of the delay circuit and the LFO circuit. There are many delays that doe not use an LDR for their LFO, if they have an LFO at all. There are many LFOs without LDRs.

But "LFO" is an abstraction for something that makes a modulation waveform. Exactly how the waveform modulates whatever it modulates depends critically on the circuit being modulated, and whether it takes a variable resistance, variable voltage, variable current, variable amount of light to make it wobble, and once that's picked out, exactly how much DC and AC of each of those to make the circuit perform as expected. Sometimes mating the oscillator portion of an LFO to the modulator portion of the circuit is tricky and picky.

So - there is no way to answer your question without knowing what delay and what LFO.