Photodetector
Photodetector
Protective tariff
<i>Photosensors</i> or <i>photodetectors</i> are <a href="Sensor">sensors</a> of <a href="Light">Light</a> or other <a href="Electromagnetism">electromagnetic</a> energy and can appear in several varieties:<ul><li><a href="Photoresistor">Photoresistors</a> or Light Dependant Resistors (LDR) which change <a href="Resistance">Resistance</a> when illuminated </ul><ul><li><a href="Solar cell">Photovoltaic</a> cells or <a href="Solar cell">solar cells</a> which produce a <a href="Volt">voltage</a> and supply an <a href="Current (electricity)">electric current</a> when illuminated </ul><ul><li><a href="Photodiode">Photodiodes</a> which can operate in photovoltaic mode or photoconductive mode </ul><ul><li><a href="Photomultiplier">Photomultiplier tubes</a> containing a <a href="Photocathode">Photocathode</a> which emits <a href="Electron">electrons</a> when illuminated, the electrons are then amplified by a chain of <a href="Dynode">dynodes</a>. </ul><ul><li><a href="Photomultiplier">Phototubes</a> containing a <a href="Photocathode">Photocathode</a> which emits <a href="Electron">electrons</a> when illuminated and in general behaves as a photoresistor. </ul><ul><li><a href="Photodiode">Phototransistors</a> incorporating one of the above sensing methods </ul><ul><li>Sensors that detect light via a change in <a href="Temperature">Temperature</a> due to illumination, such as <a href="Pyroelectricity">pyroelectrics</a> </ul>