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The electric part of such a meter is an electromagnetic measuring instrument which is connected to the anode and cathode of a selenium photo cell that produces more or less electric power when exposed to more or less light. The optical part of such a meter is a window in front of the photo cell's light-sensitive side.
A microwave power meter is an instrument which measures the electrical power at microwave frequencies typically in the range 100 MHz to 40 GHz. Usually a microwave power meter will consist of a measuring head which contains the actual power sensing element, connected via a cable to the meter proper, which displays the power reading.
An optical power meter (OPM) is a device used to measure the power in an optical signal. The term usually refers to a device for testing average power in fiber optic systems. Other general purpose light power measuring devices are usually called radiometers , photometers , laser power meters (can be photodiode sensors or thermopile laser ...
For very low-power systems, such as mobile phones, signal strength is usually expressed in dB-microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt . In broadcasting terminology, 1 mV/m is 1000 μV/m or 60 dBμ (often written dBu).
Multi-junction cell efficiency has now reached 44% in production cells. [citation needed] The 44% value given above is for a specific set of conditions known as "standard test conditions". These include a specific spectrum, an incident optical power of 850 W/m 2, and a cell temperature of 25 °C. In a concentrating system, the cell will ...
There were a few particularly sophisticated film SLRs including the Olympus OM-2, the Pentax LX, the Nikon F3, and the Minolta 9000, where metering cells located at the bottom of the mirror box were used for ambient light metering, depending on model either instead or in addition to metering cells in the roof of the camera. Depending on model ...
In a battery electric vehicle (BEV), the state of charge indicates the remaining energy in the battery pack. [4] It is the equivalent of a fuel gauge.. The state of charge can help to reduce electrical car's owners' anxiety when they are waiting in the line or stay at home since it will reflect the progress of charging and let owners know when it will be ready. [5]
The nonlinear I-V curve characteristic of a given cell in specific temperature and insolation conditions can be functionally characterized by a fill factor (FF). Fill factor is defined as the ratio of the maximum power from the cell to the product of open circuit voltage V oc and short-circuit current I sc. Tabulated data is often used to ...