Abstract: A harmonic bridge for use with guitars and other string instruments having fretted fingerboards includes a frame above the strings and transverse to the fingerboard in a position directly over a fret. A string contacting member is mounted in the frame above a string. Height adjustment, of the frame supports or/and of the string contacting member with respect to the frame, is provided so that the lower surface of the string contacting member can be caused to depress the string by an amount just sufficient to stop string vibration at the contact point when the string is plucked, but not far enough to cause the string to touch the fret or fingerboard.

Abstract: An electric flash apparatus of the present invention is actuated to emit light by application of a trigger signal issues by a trigger circuit (5) after a power transistor (4), such as, an I.G.B.T. (insulated gate bipolar transistor) connected in series with a flash tube (3), is certainly turned to sufficient ON state.

Abstract: An exposure apparatus comprising lighting means such as ultra-violet lamp and reflecting mirror placed in an exposure room and also tray arranged to move in and out from the exposure room, wherein cooling means is provided. The cooling means blows cold air onto the surface of the tray.A cooling room is formed next to the exposure room. The cooling means is composed of air radiator and air fan. Refrigerant such as cold water passes through the air radiator and the air fan blows air in the cooling room onto the surface of the tray through the radiator. Exhaust fan arranged to send air in the exposure room into the cooling room is also provided between the exposure room and the cooling room.

Abstract: A musical instrument comprises a tremolo apparatus which may be converted from a semi-floating mode in which a spring urged stop engages a movable sustain block in some positions thereof to a free-floating mode in which the spring-urged stop does not engage the sustain block in any position thereof. The spring-urged stop is provided with a releasable latch for latching it into the non-engaging position, the latch including a bayonet joint. An indicator apparatus indicates the position of the sustain block relative to a fixed reference target, to enable rapid location of the sustain block for the tuned position of the strings of the instrument. A pusher block of magnetic material is provided for insertion between the sustain block and the spring-urged stop for assistance in urging the spring to the position in which it is locked out of engagement with the sustain block, to establish the free-floating mode.

Abstract: An electromagnetic drive circuit comprises a coil for detecting and driving a permanent magnet; a comparator for generating an output when the induced voltage of the coil exceeds a reference voltage; a pulse generator for generating a drive pulse train in response to generation of the output of the comparator; a driver responsive to the drive pulse train for feeding a drive current to the coil; and a controller responsive to interruption of the output of the comparator for interrupting generation of the drive pulse train of the pulse generator. The permanent magnet is detected and driven by the single coil so that the output may be generated by the comparator when the induced voltage of the coil exceeds the reference value, and the drive pulse train is generated during generation of that output to feed the drive current to the coil. The coil can always be efficiently driven at the maximal point of the induced voltage, and the permanent magnet can be driven with a stable amplitude.

Abstract: Static neutralizer for a tape dispenser in which a roll of tape is rotatably supported for drawing off selected lengths in strips comprises first brush means in juxtaposition with a surface of a tape portion radially peeled from the roll, second brush means in juxtaposition with an outer surface of the tape which has just been bared by the tape portion previously peeled from the roll, and a conductive path electrically interconnecting the first and second brush means, whereby any charges developed on the peeled-away portions of the tape are neutralized prior to dispensing. The respective brush means may be made of carbon or stainless steel fibers whose ends can be adjacently spaced from the corresponding charged surface thereby acting as an induction ionizer with respect thereto or in actual contact with such surfaces and defining a passive static eliminator.

Abstract: A polarity insensitive flash driver circuit for use in a photographic system including a camera for generating a flash trigger signal, and an electronic flash unit having a trigger circuit actuatable responsive to the flash trigger signal to initiate a flash illumination. This flash driver circuit includes a two conductor, polarity insensitive connector for connection to the flash driver circuit. A first gate controlled rectifier is connected between the two conductors for controllably conducting a current in a first polarity. A second gate controlled rectifier is connected between the two conductors for controllably conducting a current in a second polarity. Actuating means responsive to the flash trigger signal simultaneously actuate the first and second gate controlled rectifiers to conduct a current.