What is h parameters transistor?

Hybrid Parameters are the values which is used to find FREQUENCY RESPONSE of a low frequency transistors.

you may have doubt like why we are using only H-PARAMETERS why not HYBRID-PI models because...,

h-parameters values are constant at low frequency

moreover, at low frequency transition model we have assumed that the response of transistor to changes of input current or input voltage is instantaneous this is the reason why we had neglected shunt capacitances . as there were no shunt capacitances there is no chance of using hybrid-pi model.

i hope you got answer for your question