Experimental determination of the Planck’s constant by observation of the discharge current of a capacitor

Abstract

In this paper, we present an experimental method for the determination of Planck’s constant, based on the measurement of the discharge current of a capacitor on a LED, without the use of resistors. To develop this, we use a capacitor connected in parallel to a LED and observe the voltage on the capacitor during its discharge along with the current flowing through the ammeter connected in series to the LED. At the instant when the current becomes zero, the voltage applied on the LED corresponds to the cutoff voltage, by which we can determine the Planck’s constant. Moreover, we treat some important concepts about the quantum phenomena of the LED operation and present the results from this methodology, with some discussions.