Tag: Applied Physics
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Microwave Spectroscopy: Features, Types & Applications
Microwave Spectroscopy The section of the electromagnetic spectrum extending approximately from 1 mm (300,000 MHz) to 30 cm (1000 MHz) is referred to as the microwave region. Spectroscopic applications of microwaves consist of almost exclusively of absorption work in gaseous samples. With some exceptions, the various types of spectra are distinguished by their energy origins.…
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Microwave Active Devices: Types, Features & Operation
Generally microwave devices can be categorized as either passive components or active components. We have already talked about microwave passive components in this other article. This article focuses on microwave active devices. They may be classified into two types: low-power solid-state devices and high-power vacuum tube devices. Communications involving the gigahertz bandwidths cannot employ conventional…
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How Cellular Communication Systems Works
In cellular communication systems, there is a two-way wireless transmission between the cellular phone handset and the base station tower. The cell phone converts the audio signals into electrical form using a microphone. This information is imposed on a high frequency carrier signal by the process of modulation. The modulated carrier is radiated into free…
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How the Photoelectric Effect Influences Semiconductors
A photoelectric effect is any effect in which light energy is converted to electricity. When light strikes certain light-sensitive materials, it may cause them to give electrons or change their ability to conduct electricity or may cause them to develop an electrical potential or voltage across two surfaces. When a surface is exposed to electromagnetic…
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Metal Oxide Semiconductor FET (MOSFET)
The Metal oxide semiconductor FET (MOSFET) also known as the insulated-gate FET (IGFET) is similar to JFET but exhibits even larger resistive input impedance due to the thin layer of silicon dioxide that is used to insulate the gate from the semiconductor channel. This insulating layer forms a capacitive coupling between the gate and the…
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The Junction Field Effect Transistors (JFET)
The bipolar transistor has several disadvantages: it has low input impedance because of forward biased emitter junction, it has small high-frequency gain, it has considerable noise level and it is non-linear when |VCE| < 2V. Although low input impedance problem may be improved by careful design and use or more than one transistor, even so…
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Bipolar Junction Transistors (BJT)
By placing two PN junctions together we can create a bipolar junction transistor. In a PNP transistor the majority charger carriers are holes and typically germanium is favored for these devices. In NPN transistors the majority charger carriers are electrons; for this case, silicon is typically used. The thin and lightly doped central region is…
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The Basics Facts about Photons
Photons are the elemental units of electromagnetic spectrum. For example, white light is composed of a number of different kinds of photons, some are red photons, some are blue photons, etc. Note that, there is no white photon; instead the combination of the various colored photons when they interact with your eyes, your brain perceives…