#Light intensity equation circuit free#

Photojunction devices are specifically designed for detector application and light penetration with their spectral response tuned to the wavelength of incident light. Photo-junction Devices – These photodevices are mainly true semiconductor devices such as the photodiode or phototransistor which use light to control the flow of electrons and holes across their PN-junction.The most common photovoltaic material is Selenium used in solar cells. Light energy falls on to two semiconductor materials sandwiched together creating a voltage of approximately 0.5V. Photo-voltaic Cells – These photodevices generate an emf in proportion to the radiant light energy received and is similar in effect to photoconductivity.The most common photoconductive material is Cadmium Sulphide used in LDR photocells. Thus, more light increase the current for a given applied voltage. Photoconductivity results from light hitting a semiconductor material which controls the current flow through it. Photo-conductive Cells – These photodevices vary their electrical resistance when subjected to light.The amount of energy the photons have depends on the frequency of the light and the higher the frequency, the more energy the photons have converting light energy into electrical energy.

#Light intensity equation circuit free#

Photo-emissive Cells – These are photodevices which release free electrons from a light sensitive material such as caesium when struck by a photon of sufficient energy.Photoelectric devices can be grouped into two main categories, those which generate electricity when illuminated, such as Photo-voltaics or Photo-emissives etc, and those which change their electrical properties in some way such as Photo-resistors or Photo-conductors. Light sensors are more commonly known as “Photoelectric Devices” or “Photo Sensors” because the convert light energy (photons) into electricity (electrons). The light sensor is a passive devices that convert this “light energy” whether visible or in the infra-red parts of the spectrum into an electrical signal output. The lower the energy the light, the less work can be done with it by the atom when it absorbs that light.A Light Sensor generates an output signal indicating the intensity of light by measuring the radiant energy that exists in a very narrow range of frequencies basically called “light”, and which ranges in frequency from “Infra-red” to “Visible” up to “Ultraviolet” light spectrum. Radio waves cause nuclear spin transitions which is when a proton changes its spin state. Microwaves cause rotational motion where a molecule rotates. The bonding atoms of a molecule vibrate back and forth like an oscillating spring. Infrared light causes molecular vibrations. The electrons are able to move between the energy levels within the atom, but do not have enough energy to escape. Low energy UV and visible light cause electron transitions. They transfer enough energy to electrons so they can escape from the pull of the atom’s nucleus and turn the atom into an ion. Higher energy light such as gamma rays, X-rays, and high energy UV light cause ionizations. And since energy and frequency are directly proportional, the trend we describe using energy will be the same for frequency. The different effects light has on atoms can best be understood when considering the energies of types of light.