Eur. Phys. J. Appl. Phys. 34, 117-121 (2006)
https://doi.org/10.1051/epjap:2006044

A theory of filament lamp's failure statistics

¹ Department of Physics, Banaras Hindu University, Varanasi 221005, India
² Department of Farm Engineering, Banaras Hindu University, Varanasi 221005, India

Corresponding author: dca_bhu@yahoo.com

Received: 23 September 2005
Revised: 8 March 2006
Accepted: 17 March 2006
Published online: 18 May 2006

Abstract

We model the ejection of tungsten atoms from a hot filament by a binomial distribution. A normal approximation is made and the lamp is supposed to fail if the undecayed atomic fraction drops below a critical value. The resulting formula for the lamp survival probability has no free parameter and is shown to be in excellent agreement with the experimental mortality curve.