3B SCIENTIFIC® PHYSICS
Light emitting diodes for determining Planck’s constant (h) 8482460
Instruction sheet
07/06 SP
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.
1 |
Sockets for LED’s (anode) |
2 |
LEDs, blue to infrared |
3 |
Socket for 100 series resistor |
4Series resistor on (rear of) circuit board 100
5 Socket for common cathode
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 current/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.
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