  Large Area X-ray Propositional Counter (LAXPC) instrument on AstroSat is
aimed at providing high time resolution X-ray observations in 3 to 80 keV
energy band with moderate energy resolution. To achieve large collecting area,
a cluster of three co-aligned identical LAXPC detectors, is used to realize an
effective area in access of about 6000 cm2 at 15 keV. The large detection
volume of the LAXPC detectors, filled with xenon gas at about 2 atmosphere
pressure, results in detection efficiency greater than 50%, above 30 keV. In
this article, we present salient features of the LAXPC detectors, their testing
and characterization in the laboratory prior to launch and calibration in the
orbit. Some preliminary results on timing and spectral characteristics of a few
X-ray binaries and other type of sources, are briefly discussed to demonstrate
that the LAXPC instrument is performing as planned in the orbit.
