Loud speakers

Newman and Lerner (N2) have used an arrangement where the signal picked up by a microphone attached to the flat surface below the orifice plate is amplified and fed to a loud speaker. The amplified bubble signal is then fed to one pair of fixed contacts of a double-pole double-throw switch of which the other pair of fixed contacts is connected to an audio-frequency generator. The movable contacts of the switch are connected to the vertical and ground terminals of an oscilloscope. This arrangement permits the observation of either the bubble signal or the sine wave as a function of the internal linear time-base of the oscilloscope. 

Several polymers also are effective piezoelectric materials. The best known of these is PVDF (Equation 6.55), which is employed in loud speakers, fire and burglar alarm systems, earphones, and microphones. 

A somewhat detailed description of one complete set of readings (experiment No. 33, on May 24th), taken with the loud speaker, will now be given. Column 1, of table 1, contains the time at which the counting... 

NUMBER OP EXPERIMENT DATE HEATING CURRENT AMPERES TUBE CURRENT MILLIAMP. LOUD SPEAKER COUNTED IN DEGREES OP 5 MINUTES POLARIZATION RECORDER degrees OP POLARIZATION... 

A very sensitive modification of this method has been described by Zisman 1 one of the plates is made to vibrate rapidly parallel to itself, thus periodically altering the distance between the plates. The oscillating current thus caused to flow to and from the plate is amplified and operates a loud speaker. A potentiometer is used to vary the potential applied to the plates, until the sound vanishes, and the value of the applied potential is then the contact potential. 

They also conceived the idea of energizing a dynamic type of loud speaker from an alternating current house-lighting circuit, and reduced the invention to practice on Jan. 25, 1922. On March 21, 1922, they filed an application for a power amplifier. The conception embodied in this patent was devised by the patentees without suggestion, instruction, or assignment from any superior. 

With respect to instrumentation, new and faster Monitrons (ion chambers and associated circuits) were added so that three were in operation at all times and all were connected to the control rod safety system. The time, constants of the safety circuits were about 0.2 to 0,5 sec. Eaterline>Angus recorders installed in the control room were driven by two of the Monitrons so that visual monitoring of the pile was provided. In addition, the usual array of counters, gamma ray and neutron, were in use with mechanical recorders for counting rate purposes and loud speakers for continuous auditory monitoring. 

The spherical loud speakers were also manufactured with a tool that allowed the manufacturing within one single mould. 

The Stokes-layer excitation in a cylindrical duct is one of the effective techniques for dynamic calibration of shear stress sensors [8]. The flow inside the duct is driven by an oscillating pressure gradient generated by a loud speaker (see Fig. 10). The loud speaker driven by an amplifier generates an acoustic wave. The amplifier receives sinusoidal input from a function generator. The microphone and shear stress sensor are mounted at opposite locations of the tube. The data acquisition system records the signal from the microphone and shear stress sensor. 

PLA is used as the base material for hosings for loud speakers. Further, the composition contains aluminum hydroxide as inorganic filler, and a hydrolysis inhibitor (22). 

I started my scientific career in Sony as a researcher on zinc-air hatteries. After 8 years of R D on electrochemistry, my research field was shifted against my will to electroacoustic materials, specifically materials for diaphragms of electroacoustic transducers including loud speakers, headphones, and microphones. 

Extensively used in the woodworking and packaging industries, the adhesives have applications with fabrics and fabric-based components used in engineered products, for example loud-speaker cones. They also bond ceramics well. Normally used for relatively lightly-loaded materials - preferably in good environments. 

Thus there are many piezo devices using these phenomena. Microphone membranes (PE), loud speakers (RPE), sonar (historically the first application RPE), piezoresistors (PR) for pressure measurements, cigarette lighters (PE), and quartz watches (RPE) are examples. 

FIGURE 3.40 Simulated spherical loud-speaker. The housing is perforated with many small holes. The voice coils are connected 180 out of phase. Source Termaine, H.M. 1973. Audio Cyclopedia, 2nd ed., p. 111. Howard Sams.)... 

One type of sonar transducer, primarily used in the surveillance community, is a low-frequency active source. The tonpilz design is commonly used for such projectors at frequencies down to about 2 kHz (a tonpilz at this frequency is almost 0.75-m long). For frequencies below 2 kHz, other types of transducer technology are employed, including mechanical transformers such as flexing shells, moving coil (loud speaker) devices, hydraulic sources, and even impulse sources such as spark gap and air. Explosives are a common source for surveillance, and when used with towed arrays make a very sophisticated system. 

Loud speaker, smart wall paper Flat-paper loudspeakers on walls Active/semiactive noise suppression Dielectric elastomers High voltage... 

PTC devices are available in a range of specifications to meet defined requirements in low voltage electronic circuits where they may, for example, protect automotive electronic circuits, cellular phones, laptop computers, loud speakers, power transformers, rechargeable battery packs, security and fire alarm systems and other products. 

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