  We present the V band variability analysis of the point sources in the Faint
Sky Variability Survey on time scales from 24 minutes to tens of days. We find
that about one percent of the point sources down to V = 24 are variables. We
discuss the variability detection probabilities for each field depending on
field sampling, amplitude and timescale of the variability. The combination of
colour and variability information allows us to explore the fraction of
variable sources for different spectral types. We find that about 50 percent of
the variables show variability timescales shorter than 6 hours. The total
number of variables is dominated by main sequence sources. The distribution of
variables with spectral type is fairly constant along the main sequence, with 1
per cent of the sources being variable, except at the blue end of the main
sequence, between spectral types F0--F5, where the fraction of variable sources
increases to about 2 percent. For bluer sources, above the main sequence, this
percentage increases to about 3.5. We find that the combination of the sampling
and the number of observations allows us to determine the variability
timescales and amplitudes for a maximum of 40 percent of the variables found.
About a third of the total number of short timescale variables found in the
survey were not detected in either B or/and I. These show a similar variability
timescale distribution to that found for the variables detected in all three
bands.
