Category Everyday Science

A loudspeaker works like a reversed microphone. Electric current flows into a coil of wire, turning it into an electromagnet. This attracts the coil to another magnet inside the loudspeaker, causing the coil to vibrate. This vibrates a diaphragm at the same frequency as the original sound, pushing air in front of it to carry the sound to the ears of the listeners. Many loudspeakers can be connected together, so that sound is heard all around a large outdoor or indoor space.

A loudspeakers (loud-speaker or speaker) is an electroacoustic transducer which converts an electrical audio signal into a corresponding sound.

A loudspeaker consists of paper or plastic moulded into a cone shape called ‘diaphragm.’ When an audio signal is applied to the loudspeaker’s voice coil suspended in a circular gap between the poles of a permanent magnet, the coil moves rapidly back and forth due to Faraday’s law of induction. This causes the diaphragm attached to the coil to move back and forth, pushing on the air to create sound waves.

Voice coil, usually made of copper wire, is glued to the back of the diaphragm. When a sound signal passes through the voice coil, a magnetic field is produced around the coil causing the diaphragm to vibrate. The larger the magnet and voice coil, the greater the power and efficiency of the loudspeaker.

The coil is oriented co-axially inside the gap; the outside of the gap being one pole and the centre post (called as the pole piece) being the other. The gap establishes a concentrated magnetic field between the two poles of the permanent magnet. The pole piece and backplate are often a single piece, called the pole plate.

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Inside a microphone is a metal disc, called a diaphragm. When a sound wave hits the sensitive diaphragm, it makes it vibrate at the same frequency. This causes a wire coil, beneath the diaphragm, to move up and down. As the coil comes near to a magnet below, it creates a pulse of electric current in the wire. The pattern of these pulses matches the pattern of the sound wave. The pulses can be sent along a wire to a loudspeaker, to be turned back into sound, or they can be recorded on a tape or compact disc.

When you speak, sound waves created by your voice carry energy toward the microphone. Remember that sound we can hear is energy carried by vibrations in the air. Inside the microphone, the diaphragm (much smaller than you’d find in a loudspeaker and usually made of very thin plastic) moves back and forth when the sound waves hit it. The coil, attached to the diaphragm, moves back and forth as well.

The permanent magnet produces a magnetic field that cuts through the coil. As the coil moves back and forth through the magnetic field, an electric current flows through it.

The electric current flows out from the microphone to an amplifier or sound recording device. Hey presto, you’ve converted your original sound into electricity! By using this current to drive sound recording equipment, you can effectively store the sound forever more. Or you could amplify (boost the size of) the current and then feed it into a loudspeaker, turning the electricity back into much louder sound. That’s how PA (personal address) systems, electric guitar amplifiers, and rock concert amplifiers work.

Dynamic microphones are just ordinary microphones that use diaphragms, magnets, and coils. Condenser microphones work a slightly different way by using a diaphragm to move the metal plates of a capacitor (an electric-charge storing device) and generate a current that way. Most microphones are omnidirectional, which means they pick up sound equally well from any direction. If you’re recording something like a TV news reporter in a noisy environment, or a rare bird tweeting in a distant hedgerow, you’re better off using a unidirectional microphone that picks up sound from one specific direction. Microphones described as cardioid and hypercardioid pick up sounds in a kind of “heart-shaped” (that’s what cardioid means) pattern, gathering more sound from one direction than another. As their name suggests, you can target shotgun microphones so they pick up sounds from a very specific location because they are highly directional. Wireless microphones use radio transmitters to send their signals to and from an amplifier or other audio equipment (that’s why they’re often called “radio mics”).

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A compact disc (CD) has a plastic surface on which sounds are stored in binary code as very small holes, called pits, and flat areas, called lands. These can be “read” by a laser beam. The laser beam scans across the surface of the disc. When the light falls on a pit, it is scattered, but when it falls on a land, it is reflected back to a light-sensitive detector. This in turn causes a pulse of current to pass to a loudspeaker, which converts it back into sound.

If you have read the HowStuffWorks article How CDs Work, you know that the basic idea behind data storage on a normal CD is simple. The surface of the CD contains one long spiral track of data. Along the track, there are flat reflective areas and non-reflective bumps. A flat reflective area represents a binary 1, while a non-reflective bump represents a binary 0. The CD drive shines a laser at the surface of the CD and can detect the reflective areas and the bumps by the amount of laser light they reflect. The drive converts the reflections into 1s and 0s to read digital data from the disc. See How CDs Work for more information.

Normal CDs cannot be modified — they are read-only devices. A CD-R disc needs to allow the drive to write data onto the disc. For a CD-R disk to work there must be a way for a laser to create a non-reflective area on the disc. A CD-R disc therefore has an extra layer that the laser can modify. This extra layer is a greenish dye. In a normal CD, you have a plastic substrate covered with a reflective aluminum or gold layer. In a CD-R, you have a plastic substrate, a dye layer and a reflective gold layer. On a new CD-R disc, the entire surface of the disc is reflective — the laser can shine through the dye and reflect off the gold layer.

When you write data to a CD-R, the writing laser (which is much more powerful than the reading laser) heats up the dye layer and changes its transparency. The change in the dye creates the equivalent of a non-reflective bump. This is a permanent change, and both CD and CD-R drives can read the modified dye as a bump later on.

It turns out that the dye is fairly sensitive to light — it has to be in order for a laser to modify it quickly. Therefore, you want to avoid exposing CD-R discs to sunlight.

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By putting collars with radio transmitters onto wild animals, naturalists have been able to track their movements, night and day, adding enormously to our knowledge of animal behaviour. The collars do not interfere with the animals’ normal lives. As well as learning about animal migrations and hunting patterns, naturalists are also able to discover more about the life span of animals in the wild, which may differ enormously from that of those kept in zoos and wildlife parks.

Since a protracted durable the tightlipped animals are studied by man, creating use of the many a method. Of course, within the starting it had been the employment of the fundamental explanation that helped them study animals. Folks would watch them, follow their tracks, creating interpretations etc. Those were the times of the co–existence for man and animal. The diversity of the kingdom is exploited so as that each little and enormous animals is tracked and monitored victimization constant system. Application of geoinformatics (remote sensing, Geographic system (GIS) associate degreed GPS) has enjoying an progressively vital role in conservation biology and life management by providing means that for grouping point and habitats data of life. Another advantage of the system is that the facility to integrate non–spatial knowledge directly, purpose knowledge collected from the sphere, GPS knowledge of life observance, pugmarks, scats, pellets etc. are fed directly and might generate a separate layer. But the trendy research goes on the far side the radio signals. It helps researchers to urge additional precise answers to the targeted queries concerning environs, migration patterns among others. And these answers are quantitative and analytical. Also, the advancement in technology has helped scientists to try to analysis victimization additional non–invasive means that and besides create the invasive ways safer. Each time a GPS radio collars tries to record a location it records data on the date, time and latitude. This data is then utilized to calculate the gap between locations, travel speed, location methods, direction, daily activity levels, home ranges, and analysis of spatial and temporal variations in behavior.

Recent technologies have helped solve the matter of untamed life following. Some electronic tags provide off signals that are picked up by radio devices or satellites whereas alternative electronic tags may embody deposit tags. Scientists will track the movement and locations of the labeled animals. These electronic tags will offer a good deal of information. Also, owing to their size and weight, electronic tags could produce drag on some animals, fastness them down. However, they’re costlier than the low–tech tags that are not electronic.

Tracking an animal by radio involves 2 devices. A VHF receiver picks up the signal, a bit like a home radio picks up a station’s signal. The receiver is sometimes during a truck, an ATV, or an airplane. To stay track of the signal, the soul follows the animal victimization the receiver. A transmitter attached to the animals sends out a proof within the type of radio waves, even as a radio station does. A soul would possibly place the transmitter around associate degree animal’s ankle, neck, wing, carapace, or dorsal fin. This approach of victimization radio following is accustomed track the animal manually however is additionally used once animals are equipped with alternative payloads.

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A video recorder stores television sound and pictures on a magnetic tape. It receives the electric signal that comes through a cable or aerial into the machine, then records it on tape in much the same way as a tape recorder does, although the video recorder makes diagonal tracks so that more information can be held on the tape. A record – replay head in the video recorder enables the information on tape to be sent to a television set.

Video tape recorder, also called Video Recorder, electromechanical device that records and reproduces an electronic signal containing audio and video information onto and from magnetic tape. It is commonly used for recording television productions that are intended for rebroadcasting to mass audiences. There are two types of video tape units: the transverse, or quad, and the helical.

The transverse unit uses four heads rotating on an axis perpendicular to the direction of 2-inch (5-centimetre) tape. The transverse format achieves a 1,500-inch-per-minute head-to-tape speed necessary for high picture quality. For broadcast industry needs, an audio track, control track, and cue track are added longitudinally. These units follow the standards of the North American Television Standards Commission—i.e., the electron beam sweeps 525 horizontal lines at 60 cycles per second.

The helical unit, designed for home and amateur use, uses half- or three-quarter-inch tape traveling around a drum in the form of a helix. There are various forms of these recorders: the playback deck can play back recorded programs but cannot record or erase; the video-record deck can record directly from a camera but cannot record off-the-air programs; the TV-record deck has an antenna and tuner for recording off-the-air programs. Portable reel-to-reel or cassette recorders are also produced.

Videotape has many uses in sport. For example, it may be used for an “action replay”, to check what really happened in a fast-moving sport. Athletes are also able to study videotape in order to see where they are making errors and so improve their technique.

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