- The term "loudspeaker" may refer to individual transducers (known as "drivers") or to complete speaker systems consisting of an enclosure including one or more drivers.
- The diaphragm is usually manufactured with a cone- or dome-shaped profile. A variety of different materials may be used, but the most common are paper, plastic, and metal
- The chassis, frame, or basket, is designed to be rigid, avoiding deformation which would change critical alignments with the magnet gap, perhaps causing the voice coil to rub against the sides of the gap
- The suspension system keeps the coil centered in the gap and provides a restoring (centering) force that returns the cone to a neutral position after moving.
- The advantage of aluminum is its light weight, which raises the resonant frequency of the voice coil and allows it to respond more easily to higher frequencies
- Modern driver magnets are almost always permanent and made of ceramic, ferrite, Alnico, or, more recently, rare earth such as neodymium and Samarium cobalt
- The size and type of magnet and details of the magnetic circuit differ, depending on design goals
- Individual electrodynamic drivers provide optimal performance within a limited pitch range. Multiple drivers
- Full-range drivers often employ an additional cone called a whizzer: a small, light cone attached to the joint between the voice coil and the primary cone.
- A woofer is a driver that reproduces low frequencies. The driver combines with the enclosure design to produce suitable low frequencies
- A sound card (also known as an audio card) is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs.
- Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education, and entertainment
- Sound cards usually feature a digital-to-analog converter (DAC), which converts recorded or generated digital data into an analog format. The output signal is connected to an amplifier, headphones, or external device using
- An important characteristic of sound cards is polyphony, which is more than one distinct voice or sound playable simultaneously and independently, and the number of simultaneous channels
- Sound cards for computers compatible with the IBM PC were very uncommon until 1988, which left the single internal PC speaker as the only way early PC software could produce sound and music
- The Sound Blaster line of cards, together with the first inexpensive CD-ROM drives and evolving video technology, ushered in a new era of multimedia computer applications
- Most new soundcards no longer have the audio loopback device commonly called "Stereo Mix” that was once very prevalent and that allows users to digitally record speaker output to the microphone input
- Professional soundcards are special soundcards optimized for real-time (or at least low latency) multichannel sound recording and playback, including studio-grade fidelity
- USB sound "cards" are mostly external boxes that plug into the computer via USB. They are sometimes called audio "interfaces" rather than sound-cards,
- Soundcards using the PCMCIA cardbus interface were popular in the early days of portable computing when laptops and notebooks did not have onboard sound.
- An image scanner—often abbreviated to just scanner— is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image
- Modern scanners typically use a charge-coupled device (CCD) or a Contact Image Sensor (CIS) as the image sensor, whereas older drum scanners use a photomultiplier tube as the image sensor
- scanner is digital camera scanners, which are based on the concept of reprogramming cameras
- Drum scanners capture image information with photomultiplier tubes (PMT), rather than the charge-coupled device (CCD) arrays found in flatbed scanners and inexpensive film scanners
- A flatbed scanner is usually composed of a glass pane (or platen), under which there is a bright light (often xenon or cold cathode fluorescent) which illuminates the pane, and a moving optical array in CCD scanning.
- Hand scanners come in two forms: document and 3D scanners. Hand held document scanners are manual devices that are dragged across the surface of the image to be scanned
- One printer manufacturer has introduced all-in-one printer which is provided with a desktop digital camera scanner that has 10 megapixel image sensors. For scanning a business card or a full 8.5x11 inch image
- Cameras in smartphones have reached a resolution and quality that reasonable quality scans can be achieved by taking a photo with the phone and using a scanning app for post-processing
- Scanners typically read red-green-blue color (RGB) data from the array. This data is then processed with some proprietary algorithm to correct for different exposure conditions
- Scanning the document is only one part of the process. For the scanned image to be useful, it must be transferred from the scanner to an application running on the computer.
- A printer is a peripheral which produces a text and/or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies
- Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most newer printers, a USB cable to a computer which serves as a document source
- Consumer and some commercial printers are designed for low-volume, short-turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given document
- A virtual printer is a piece of computer software whose user interface and API resemble that of a printer driver, but which is not connected with a physical computer printer.
- A laser printer rapidly produces high quality text and graphics. As with digital photocopiers and multifunction printers (M Fps), laser printers employ a xerographic printing process
- Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized page. They are the most common type of computer printer used by consumers.
- Solid ink printers, also known as phase-change printers, are a type of thermal transfer printer. They use solid sticks of CMDR-colored ink, similar in consistency to candle wax,
- A dye-sublimation printer (or dye-sub printer) is a printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, paper or canvas.
- Thermal printers work by selectively heating regions of special heat-sensitive paper. Monochrome thermal printers are used in cash registers, At Ms, gasoline dispensers and some older inexpensive fax machines.
- Most microphones today use electromagnetic induction, capacitance change , piezoelectric generation, or light modulation to produce an electrical voltage signal from mechanical vibration.
- The sensitive transducer element of a microphone is called its element or capsule. A complete microphone also includes a housing
- RF condenser microphones use a comparatively low RF voltage, generated by a low-noise oscillator.
- Condenser microphones span the range from telephone transmitters through inexpensive karaoke microphones to high-fidelity recording microphones.
- An electron microphone is a relatively new type of capacitor microphone invented at Bell laboratories in 1962 by Gerhard Sessile and Jim West.
- Dynamic microphones work via electromagnetic induction. They are robust, relatively inexpensive and resistant to moisture.
- A carbon microphone, also known as a carbon button microphone (or sometimes just a button microphone), use a capsule or button containing carbon granules pressed between two metal plates like the Berliner and Edison microphones
- A crystal microphone or Pietro microphone uses the phenomenon of piezoelectric — the ability of some materials to produce a voltage when subjected to pressure — to convert vibrations into an electrical signal.
- A fiber optic microphone converts acoustic waves into electrical signals by sensing changes in light intensity, instead of sensing changes in capacitance
