  A photometric variability study of a sample of northern field stars, which
previously classified as either PMS or Herbig Ae/Be objects, has been
undertaken with the purpose of detecting {\delta} Scuti-type pulsations.
Determination of physical parameters for these stars has also been carried out
to locate them on the HR diagram and check the instability strip for this type
of pulsators. Multichannel photomultiplier and CCD time series photometry in
the uvby Str\"omgren and BVI Johnson bands were obtained during four
consecutive years from 2007 to 2010. The light curves have been analysed, and a
variability criterion has been established. Among the objects classified as
variable stars, we have selected those which present periodicities above 4
d^(-1), which was established as the lowest limit for {\delta} Scuti-type
pulsations in this investigation. Finally, these variable stars have been
placed in a colour-magnitude diagram using the physical parameters derived with
the collected uvby{\beta} Str\"omgren-Crawford photometry. Five PMS {\delta}
Scuti- and three probable {\beta} Cephei-type stars have been detected. Two
additional PMS {\delta} Scuti stars are also confirmed in this work. Moreover,
three new {\delta} Scuti- and two {\gamma} Doradus-type stars have been
detected among the main-sequence objects used as comparison or check stars.
