A pulsar is a rapidly spinning neutron star – the remnant of a supernova explosion. It has a powerful magnetic field, shooting out jets of radiation that sweep across space like lighthouse beams – when they line up with Earth they appear as a rapidly repeating burst of light, radio waves and other radiations.
A quasar is in fact a distant galaxy with a fluctuating blaze of light and other radiations coming from its central regions. The activity in these galaxies is caused by a giant black hole at their very heart, pulling in material from its surroundings, tearing it to shreds and heating it up to tremendous temperatures before swallowing it up.
So technically these two are complete different thing only name is looking similar.