3B Scientific Determination of Planck's Constant (h) Apparatus - Manual

3B SCIENTIFIC® PHYSICS
1
Light emitting diodes for determining Planck’s constant (h)
8482460
Instruction sheet
07/06 SP
1 Sockets for LED’s (anode)
2 LEDs, blue to infrared
3 Socket for 100 series resistor
4 Series resistor on (rear of) cir-
cuit board 100
5 Socket for common cathode
1. Safety instructions
• When the diodes are brightly illuminated, avoid
looking directly at the radiating surface.
• Do not exceed the maximum current.
• Do not operate the diodes without the series
resistor.
• Do not allow any liquid to enter the equipment.
2. Description
The equipment is used to determine Planck’s constant
h by measuring the diffusion voltage of multicoloured
LEDs as a function of wavelength or frequency. It is
also possible to determine wavelengths by means of
lattice diffraction, as well as the relation between
luminous intensity and current. In addition, the
equipment can also be used to determine the cur-
rent/voltage characteristic curves for the LEDs. The
circuit board is equipped with six LEDs in the colours
blue, green, yellow, and three different wavelengths
of red. The cathodes are lall connected to a common
rail. The resistor serves as a protection and should
always be connected in series when operating the
diodes.