Planck'S Constant Apparatus Standard Model

BESTO Planck's constant Appt. is an instrument to obtain Planck's Constant. A suitable light source provides light energy to photo tube. Three different colours of filters are used is between light source & photo tube to select the different wavelength. A vacuum photo tube is kept inside the tube housing. DC variable regulated power supply of 0-1V, provides stopping potential for electrodes & the ammeter gives accurate current output (in range of few microamperes) measurement facility.