Description

This apparatus is designed to determine the
approximate value of Planck’s Constant using the
elbow voltage inthe characteristics curves of a
number of LEDs. There are seven LEDs covering
from deep blue at 470 nm to near IR 940 nm
mounted on the box with sockets for voltage
and current measurements. By monitoring
the voltage at which each LED begins to emit
light a graph of energy input as a function of
light emitted frequency can be plotted and an
approximate value of Planck’s Constant can be
deduced. External 9V power source or 9V battery
and connecting leads required.