I'm sure you'll get more authoritative answers from other users but my
experience with phasor can be summed up as follows:

Phasor produces a stream of values at a-rate (k-rate also?) running from 0
to 1 and can cycle through these at a cps rate. The output can then be used
to index a function table (such as one containing a sinusoid - although
other shapes are possible) via the table opcodes. In other words, it can
enable your instrument to read values from a table at the audio (or k?) rate
and keep doing so at a specified cps (ie if cps is 1 then phasor will read
through the table once every second; if cps is 440 you'll get a pitch).
That's how it simulates an oscillator. It can, like so much of CSound, be
used in other ways such as indexing the analysis files for phase vocoders.

I'm not sure how your using it but if its being used on its own you will
only get a signal extending to the value of 1 - which is virtually silence.
If you were to amplify this signal by a large number you would, I imagine,
get some sort of sawtooth wave at the specified cps.

Hope that helps,

Richard.