This specification discloses a novel dynamic microphone using a flat annular magnet formed of an anisotropic barium ferrite as a permanent magnet to establish a magnetic circuit. The present microphone is extremely flat and of an excellent tone quality, and it can be manufactured at low cost. Various modifications to the microphone of this type become easily possible, and therefore a variety of examples with unidirectional characteristics or other characteristics are disclosed in this specificat...

An electromagnetic loudspeaker with a magnetic structure provided with a cylindrical gap and a frame supporting a diaphragm, the diaphragm carrying a voice coil suspended in the gap of the magnetic structure, the magnetic structure being provided with a thin coating of plastic such as teflon or nylon confronting the voice coil to prevent abrasion or shorting of the voice coil in the event the voice coil contacts the magnetic structure.

A dynamic seal is provided, comprising a gland, fixedly connectible to a housing around a rotatable shaft and having a first side, facing interior of the housing; a second side, facing exterior of the housing; a center opening, communicating between the first and second sides; and having a diameter greater than that of the shaft; an annular inner face, countersunk into the second side adjacent to the center opening so as to form an interior groove between the shaft and the gland; an annular firs...

When half-size dummy cells are used in a dynamic memory, it is difficult to increase the relative accuracy of the capacitors in the half-size dummy cells and the capacitors in memory cells. According to the present invention, a pair of full-size dummy cells is provided connected to a pair of bit lines. High-level and low-level signals amplified by the sense amplifier are written into the full-size dummy cells, the capacitors of the pair of full-size dummy cells are then short-circuited by a shor...

A dynamic damper includes a metallic weight having a predetermined resonance frequency, a support member to be connected to an oscillating member in a vehicle to which the damper is applied, a rubber resilient member bonded by vulcanization to the metallic weight and the support member, a cover member attached to the support member in fluid-tight sealing relation thereto and encircling the support member, the resilient member and a part of the metallic weight, and a membrane secured on the metal...

In a dynamic RAM, the refreshing operation is performed during one cycle of the read or write operation. A switch circuit selects either a row address signal output from address input circuit or a refresh row address signal output from a refresh circuit. By controlling the switch circuit by a switch selector, the refresh is performed during the operation delay time of the address input circuit or an input/output circuit for inputting and outputting data.

In a dynamic optometer, a variation in the direction of a subject's eye, namely, in the direction of gaze is measured by a direction detector to tilt a bi-axial rocking mirror according to the output of the detector, and an actual image of an eyeball formed by a pair of concave spherical mirrors is reflected to an optical system by the rocking mirror varying the direction of incidence. A second actual image which is formed immediately before a light source by the optical system is stably fixated...

A dynamic memory having pairs of bit lines. A sense amplifier is connected between each pair of bit lines for detecting data from the potential difference between these bit lines. The memory further comprises first and second pair of dummy word lines. A capacitor is coupled between the first of each pair of bit lines, on the one hand, and the first pair of dummy word lines, on the other. Similarly, a capacitor is coupled between the second of each pair of bit lines, on the one hand, and the seco...

A screening apparatus is provided for removing cartiledge, gristle and bone fragments from a ground moist product such as ground meat, the screening process comprising a form of extrusion between closely spaced helically corrugated revolving cylinders. The corrugations have sinusoidal contours with the contours of adjacent cylinders displaced 180 degrees from each other. The cylinders all revolve in the same direction so that spacing between the adjacent cylinders remains fixed and uniform while...

An automatic dynamic equalization circuit has a potentiometer having a tap shunted by an active resonator circuit including a capacitor shunted by an active circuit presenting a high Q inductive reactance that is resonant at substantially 50 Hz and provides essentially no boost in the middle range of frequencies above 150 Hz with roll-off below about 45 Hz.