Description
Lascells Plancks Constant-Modern LEDs (light emitting diodes) cover the range from deep blue (430nm) to infrared (950nm). By monitoring the voltage at which each LED just 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 deduced. The system is an excellent illustration of modern electronics and gives a good investigation into a difficult topic in Post-16 physics. The LEDs are mounted in a box with voltage control and monitoring points for current and voltage. A protection resistor is included to prevent damage to the LEDs. Complete with viewing tube but without power supply which should be approximately 5V DC from any laboratory source.