摘要:
A pulse width modulated signal amplifier comprises a DC power supply for rectifying an AC input voltage to produce a pair of DC voltages of opposite polarity, a pulse width modulated signal amplifying circuit supplied with a pulse width modulated signal to produce a demodulated signal through a low pass filter, and a detecting circuit responsive to an abnormal level of the DC voltages to produce a detecting signal when a smoothing condenser of the DC power supply is overcharged by a current flowing through the low pass filter in one direction. Such detecting signal is desirably employed to prevent the appearance of the output signal from the pulse width modulated amplifying circuit.
摘要:
A transistor amplifier including a bipolar transistor supplied with an input signal and a field effect transistor which is directly connected to an output electrode of the bipolar transistor to amplify a signal applied thereto. The transistor amplifier has a protective circuit which senses the load impedance and actuates a protective means across an input terminal of the transistor amplifier when the sensed load impedance is lower than a predetermined value. Accordingly, the transistor amplifier is protected against overload conditions.
摘要:
A transistor inverter includes at least a pair of switching transistors, a transformer with primary and secondary windings, a DC voltage source with a pair of output terminals and a voltage reference terminal, and a rectifying circuit connected to the secondary winding of the transformer. A collector electrode of one of the switching transistors is insulated from a chassis by an insulation means comprising a first insulating layer, a conductive layer such as a heat sink and a second insulating layer. The conductive layer is electrically connected to the voltage reference terminal of the DC voltage source so as not to produce an undesirable radiation through the chassis.
摘要:
A low-noise, small-signal transistor amplifier particularly suited for use as a preamplifier in an acoustic or audio apparatus employs a field effect transistor having triode-type characteristics in a common source type amplification circuit, with the gate of the field effect transistor being connected directly to an input terminal which receives the audio signals to be amplified, the drain of the field effect transistor being connected to an output terminal, preferably through a capacitor for DC cutting, and the source of the field effect transistor being connected to a point of reference potential, such as the ground, through a parallel circuit of a resistor and a capacitor.
摘要:
A protective circuit for a transistor amplifier is disclosed which includes a load impedance detecting circuit provided between an output terminal of a transistor amplifier and a load terminal, a circuit for detecting an abrupt surge voltage of a voltage source for the amplifier and a muting circuit are provided between an input terminal of the amplifier and a reference point, the muting circuit being operative to limit an input signal applied to the input terminal of the amplifier in response to output signals of the load impedance detecting circuit. A protective circuit having a thermal sensing circuit for detecting a temperature rise of an output transistor above a predetermined level which shuts off the amplifier is described as one embodiment.
摘要:
A wireless communication module is arranged such that a radio frequency circuit board stands vertically on a first earth plate. The radio frequency circuit board includes first and second radio frequency transmission and reception circuits at both end portions, respectively. The radio frequency circuit board includes a second earth plate serving as a grounding electric potential of the radio frequency transmission and reception circuits. Feed lines from the radio frequency transmission and reception circuits are connected to the first earth plate, respectively. Ground lines of the feed from the radio frequency transmission and reception circuits, respectively, are connected to the second earth plate. Thus, vertical exciting currents flow at both end portions of the second earth plane, enabling transmission and reception of vertical polarization waves.
摘要:
Binary information previously recorded in an innermost rim side area is enabled to be stably reproduced. A record medium is formed by sequentially laminating a first information layer 2, an intermediate layer 3, a second information layer 4, and a cover layer 5 onto a substrate 1. First grooves are previously formed in the innermost rim area of the substrate 1. Second grooves are previously formed in an area where data is recorded. The first grooves are set to be shallower and narrower than the second grooves. Thus, such a situation that a BCA signal is modulated by diffraction due to the grooves can be reduced.
摘要:
In an optical device, a number of structures having higher portions or lower portions are arranged at a fine pitch equal to or shorter than a wavelength of visible light on a surface of a base. Each of the structures is arranged to form a plurality of arc track rows on the surface of the base, and to form a quasi-hexagonal lattice pattern, and the structure has an elliptical cone or truncated elliptical cone shape having a major axis in a circumferential direction of the arc tracks.
摘要:
A dial type switch mechanism is developed in which an installation space can be made as small as possible. In a dial type switch mechanism 10 furnished with a push type switch part provided in its center, and a dial switch part which operates a dial fitted around the push type switch part, there are provided: a substantially cylindrical dial knob 21, in the center of which a cavity is provided for the push type switch part to be installed; a ring-shaped joint ring 23, which is supported such that it can rotate freely relative to a front panel 6, and connects and rotates together with the dial knob 21; and a rotary bracket 24, which is joined to the joint ring 23, and in which a switch rotation shaft 24b that operates the dial type switch part is connected together with a ring-shaped member 24a via an arm 24c.
摘要:
Audio-centered information is stored on a unitary medium by using a Table-of-Contents (TOC) mechanism that specifies an actual configuration of various audio items on the medium. In particular, each one of a set of one or more Track Areas gets at least two mutually logically conforming Sub-TOCs assigned. This allows to retrieve any constituent Sub-TOC part from at least any correct copy of the Sub-TOCs. Furthermore, one or more Master-TOCs are provided for specifically pointing to each of the Sub-TOCs.