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Photodiode Definition of  Photodiode The photodiode is an optoelectronic device whose region of operation is limited to the reverse bias region. It carries current in reverse bias condition that depends upon the intensity of light falling on a P-N junction Principle of Photodiode The photodiode is a simple P-N junction diode that is reverse-biased with a battery of voltage V (Figure 4,9) Under normal conditions, a reverse saturation current (lo) flows due to thermally generated minority carriers. It is called dark current. The reverse saturation current is independent of applied reverse voltage (reverse voltage opposes the flow of majority carriers and diffusion of minority carriers is unaffected).  Minority carrier depends upon temperature, therefore, reverse solution current is a function of temperature When light falls at the P-N junction, light photons impart their energy to valence electrons to break the covalent bond. So electron and hole pairs are generated and their concentrati

Difference between Beam and Arch Today we are discussing the Difference between Beam and Arch. This Is the topic of civil engineering. ARCH CURVED SHAPED. HAVE MORE STRENGTH THAN BEAM or a curved symmetrical structure spanning an opening and typically supporting the weight of a bridge, roof, or wall above it. BEAM STRAIGHT SHAPE.LESS STRENGTH THAN ARCH or a long, sturdy piece of squared timber or metal used to support the roof or floor of a building. Difference A curved  beam  can be an  arch  but an  arch  is not necessarily made from a curved  beam . An  arch  can be fabricated from many materials. One form of an  arch  is a gravity  arch  where properly shaped stones or blocks are correctly shaped and laid so gravity holds the  arch  in place. The structural behavior of a beam is in a state of equilibrium if the constraints permit no rigid body movement upon the application of loads. Whereas an arch may be looked upon as a curved girder, either a solid rib or braced supported at it

Hydraulic Clutch Work Fig. shows a Hydraulic Clutch Work. When the clutch pedal has pressed the fluid under pressure from the master cylinder reaches the slave cylinder which is mounted on the clutch itself. The Huid under pressure actuates the slave cylinder push rod which further operates the clutch release fork to disengage the clutch. In the engaged condition when the clutch pedal is in the released position, the push rod rest against its stop due to the pedal return spring. Hydraulic Clutch Diagram The flange at the end of the valve shank contacts the spring retainer. As the plunger has moved to its rear position, the valve shank has the valve seal lifted from its seat and the seal spring compressed. Hydraulic fluid can then How past the three distance pieces and valve seal in either direction. However, when the clutch pedal is pressed to disengage the clutch, the initial movement of the pushrod and plunger permits the seal spring to press the valve to the shank and seal against i

Biochemical oxygen demand Biochemical oxygen demand (BOD) is the measurement of oxygen consumed by living microorganisms (primarily bacteria) while utilizing the organic matter present in a water or waste sample under conditions as close as possible to those that occur in nature. Microbial conversion of nitrate to nitrite will also contribute to BOD . Non-biodegradable (or refractory) organic compounds will not contribute to BOD . In order to make BOD test quantitative, the samples must be protected from the air to prevent reoxygenation as the dissolved oxygen concentration diminishes. Also, high-concentration wastes must be diluted to ensure that dissolved oxygen will be present throughout the test duration. It is important that the environmental conditions during the test be suitable for living organisms. Therefore nutrients are added to the dilution water. Nutrient blanks must be included in the test to ensure that the nutrient-enriched dilution water does not contribute to  BOD .

Depreciation Depreciation is taken from the Latin word Depretium. De Means Decrease and premium mean price. Thus the meaning of Depreciation is decreased in princes. The reduction of the value of equipment and building is known as Depreciation. Normally the power plant has age is 50 to 60 years. after its useful life, we need to maintain or change the machine or equipment of the power plant. Thus to change the machine or equipment we have to save money, this is the amount that is saved every year known as the Depreciation charge. Types of Depreciation Method 1. Straight-line method The straight-line method is a simple method to calculate  depreciation. In this method, we calculate the amount based on the initial cost divided by the useful life of the equipment if the salvage value is zero. If a salvage value is few amounts then we subtract the initial value from the salvage value and divide it by helpful life. Depreciation charge = initial value  - salvage value / Useful life Strai

Rotameter Rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It consists of a tube and float. The rotameter is standard as a result of its linear scale, relatively long measurement range, and low-pressure drop. It is very simple to install and maintain.  In the construction of the rotameter tube, it is marked in the division, and the reading of the meter is obtained from the scale reading at the reading edge of the float, which is taken at the largest cross-section of the float. Rotameter Is Used The rotameter is an Associate in Nursing industrial flowmeter wont to live the flowrate of liquids and gases. The rotameter consists of a tube and float. The float response to flow rate changes is linear, and a 10-to-1 flow varies or nonacceptance is customary. within the case of OMEGA™ laboratory rotameters, so much larger flexibility is feasible through the utilization of correlation equations. The rotameter is standard as a result of its linear scale, a c

Coherence In Physics Two waves are said to be coherent if they have the same frequency (or wavelength) and are in phase ( or have a constant phase difference between them). The coherence of a wave depends on the characteristics of its supply. The light produced by lasers is coherent light. Light from light bulbs or the sun is incoherent light. A high  coherence means high fringe visibility with excellent contrast (i.e. good black and white fringes or black and whatever color the light is) and low coherence means washed-out fringes and zero coherence means no fringes. Another necessary condition (for waves to be coherent) is therefore that both waves travel at the same speed. It can be well understood from Fig. (1) and (2). Fig. ( 1) shows a typical beam of light waves from an ordinary source traveling through space. It is a concept that establishes the limits within which a real light source can be considered ideal. It is a measure f the correlation that exists betwee