This apparatus is designed to determine the approximate value of Planck's constant, using a range of LEDs of known wavelength, to allow the electron/photon energy to be calculated. The apparatus includes 7 LEDs, covering the light range from deep blue at 470nm to near IR at 940nm, mounted on a box with 4mm sockets for attachment to a voltmeter and ammeter for voltage and current measurements. 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 can be deduced. * Requires 9V DC power supply https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2024-11-12 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2025-04-07 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2025-05-25 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2025-09-21 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2025-10-12 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2026-05-07 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2026-07-13 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2026-08-06 https://elecena.pl/product/27243904/eisco-planck-s-constant-apparatus 2026-09-22