Found 575 Articles for Physics

The dipole antenna is a widely popular antenna that is used mostly for the reception. The dipole antenna is cut and bent for effective radiation. The length of the total wire, which is being used as a dipole, equals half of the wavelength (i.e., l = λ/2). Such an antenna is called as a half-wave dipole antenna, also known as Hertz antenna. This antenna which is mostly used in radio receivers operates is around 3KHz to 300GHz.Construction & Working of Half-Wave DipoleThe edge of the dipole has maximum voltage. This voltage is alternating (AC) in nature. At the positive peak ... Read More

This is a simple diode that exhibits non-linear impedance. These diodes are mostly used at microwave detection and mixing.ConstructionA semi-conductor pellet is mounted on a metal base. A spring-loaded wire is connected with a sharp point to this silicon pellet. This can be easily mounted into coaxial or waveguide lines. The below figure gives a clear picture of this.OperationWith the contact between semiconductor and the metal, a depletion region is formed. The metal region has a smaller depletion width, comparatively. When contact is made, electron flow occurs from semi-conductor to the metal. This depletion builds up a positive space charge ... Read More

A voltage variable capacitance of a reverse biased junction can be termed as a Varactor diode. A varactor diode is a semiconductor device in which the junction capacitance can be varied as a function of the reverse bias of the diode.The CV characteristics of a typical Varactor diode and its symbols are shown in the below figure.The junction capacitance depends on the applied voltage and junction design. If the junction is reverse biased, the mobile carriers deplete the junction, resulting in some capacitance, where the diode behaves as a capacitor, with junction acting as a dielectric. The capacitance decreases with ... Read More

Generally, if the frequency of a signal or a particular band of signals is high, the bandwidth utilization is high as the signal provides more space for the other signals to get accumulated. But the high-frequency signals can’t travel long distances without getting attenuated. We have studied the transmission lines that help the signals to travel longer distances.A WaveguideMicrowaves propagate through microwave circuits, components and devices, which act as a part of Microwave transmission lines, broadly called as Waveguides.DefinitionA hollow metallic tube of the uniform cross section for transmitting electromagnetic waves by successive reflections from the inner walls of the ... Read More

Electromagnetic Spectrum has all the ranges of electromagnetic radiation. Radiation is the energy that travels and spreads out, as it propagates. Of all the waves, Microwaves are a special type of electromagnetic radiation that is used in many ways from cooking simple popcorn to study the nearby galaxies !!!ApplicationsThere are a wide variety of applications for Microwaves, which are not possible for other radiations. They are:Wireless CommunicationsFor long distance telephone callsBluetoothWiMAX operationsIn Outdoor broadcasting transmissionsIn broadcast auxiliary servicesRemote pickup unitStudio/transmitter linkDirect broadcast satellite (DBS)Personal communication systems (PCSs)Wireless local area networks (WLANs)Cellular video systems (CV)Automobile collision avoidance systemElectronicsFast jitter-free switchesPhase shiftersHF ... Read More

Geiger Muller Counter is named after its developers: Geiger and Muller. It is a metal cylinder filled with low-pressure gas sealed with a plastic or ceramic window at one end. This counter works in Geiger region with two specialities.The gas multiplication factor is so large that an avalanche dies in at one point but spreads all over the entire length of the central wire.Large output pulses are obtained as the output pulse is independent both of the energy and nature of the particles detected.The Principle of Working of GM CounterThe ionizing particle passing through the tube ionizes the gas and ... Read More

Noise is an unwanted signal which interferes with the original message signal and corrupts the parameters of the message signal. This alteration in the communication process makes the message to get altered after reaching. It is most likely to be entered at the channel or the receiver.The noise signal can be understood by having a look at the example figure below.Hence, it is understood that noise is some signal which has no pattern and no constant frequency or amplitude. It is quite random and unpredictable. Measures are usually taken to reduce it, though it can’t be completely eliminated.Most common examples ... Read More

Among the modulation systems in the communication field, the DSBSC and SSB are the mostly used once till the VSB was invented. If the carrier is suppressed and the power saved is distributed to the two sidebands, such a process is called as Double Side Band Suppressed Carrier system, or simply DSBSC.The process of suppressing one of the sidebands, along with the carrier and transmitting a single sideband is called as Single Side Band Suppressed Carrier system, or simply SSBSC or SSB. In the case of Single Sideband modulation, when a sideband is passed through the filters, the bandpass filter ... Read More

Multiplexing is the process of combining multiple signals into one signal, over a shared medium. If analog signals are multiplexed, it is Analog Multiplexing and if digital signals are multiplexed, that process is Digital Multiplexing.The process of multiplexing divides a communication channel into several number of logical channels, allotting each one for a different message signal or a data stream to be transferred. The device that does multiplexing can be simply called as a MUX while the one that reverses the process which is demultiplexing, is called as DEMUX.Types of MultiplexersThere are mainly two types of multiplexers, namely analog and ... Read More

It is quite a common view if you stay in Eastern countries that you see mirages under the hot scorching sun while driving on roads, especially during afternoons. You can find yourself to see a small pool of water on the road while there won’t be anything when you approach there. Though it is a bit surprising, there is a simple theory behind it.Why Does It Occur?Mirages happen when the land is hot and the air is cool. When the land (the asphalt road or a desert land) gets heated up due to hot sun, the air just above it ... Read More