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 transformer with an electrostatic shield body between its primary and secondary windings, one end of the shield body being connected to a zero potential point of the primary side from the AC standpoint. This reduces the capacity coupling between the primary and secondary windings. This transformer is particularly useful with an inverter.The transformer may include primary and secondary windings, each having a pair of terminals, and a magnetic core provided in connection with the primary and secondary windings magnetically. First and second static shield bodies may be provided at each side of the primary and secondary windings and therebetween, and these first and second static shield bodies are electrically connected to one terminal of the primary and secondary windings, respectively, so as to reduce the capacitance therebetween.
摘要:
A starting circuit for an inverter includes, at least, a control winding provided in connection with a saturable magnetic core of an input transformer of the inverter, a transistor and a capacitor. When a DC voltage source is activated, a discharge current of the capacitor flows through the collector-emitter circuit of the transistor and the control winding so as to start the switching operation of the inverter. A control circuit is provided for detecting a secondary voltage of the inverter so as to cut off the operation of the starting circuit after the inverter starts.
摘要:
A transistor inverter includes a pair of switching transistors each having base, emitter and collector electrodes, each of the collector and emitter circuits of which is connected between a DC voltage source through a primary winding of an output transformer, respectively, the secondary winding of which is connected to a rectifying circuit so as to produce a DC output voltage at its output. The transistor inverter also includes an input transformer with a saturable core and voltage feedback and current feedback circuits. The current feedback circuit has another transformer which controls the amount of current feedback, and the winding ratio of the primary and secondary windings is determined in connection with the current amplification factor of said first and second switching transistors in order to improve a switching speed of the switching transistors.
摘要:
A digital gain control apparatus includes a digital control signal generator producing a plurality of serial-binary coded signals, a clock pulse signal and a strobe signal. A shift register is supplied with the plurality of serial-binary coded signals and the clock pulse signal from the digital control signal generator. A latch circuit is connected to the output of the shift register and is supplied with the strobe signal from the digital control signal generator to convert the plurality of serial-binary coded signals into a plurality of parallel-binary coded signals. A decoder is connected to the output of the latch circuit to produce a plurality of control signals from the plurality of parallel-binary coded signals. A function selector circuit and a volume adjusting circuit for the selected functions is also provided, each being controlled by the plurality of control signals. The shift register, latch circuit and volume adjusting circuit are formed in one chip-integrated circuit. In one embodiment, a bass and treble tone control circuit is provided which is controlled by the output of the decoder.
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:
An amplifier comprised of a field effect transistor whose gate electrode is adapted to receive an input signal. An impedance converter couples the input signal to the gate electrode of the field effect transistor, the impedance converter being formed of n impedance converting stages, each stage having a relatively low output impedance. A voltage limiting circuit is connected between the source of input signal and the gate electrode of the field effect transistor so as to limit the forward biasing of the field effect transistor. This voltage limiting circuit includes m voltage-limiting elements, wherein n and m are integers (1, 2, 3, . . . ) and n is equal to or greater than m. In a preferred embodiment, the amplifier is formed of two field effect transistors connected in push-pull relation, each field effect transistor being provided with an impedance converter and a voltage-limiting circuit as described above.
摘要:
An amplifier having ready application as an amplifier for pulse width modulated signals, is comprised of first and second field effect transistor devices which exhibit triode-type dynamic characteristics. These field effect transistor devices are connected in push-pull amplifying relation for receiving a signal to be amplified and for supplying an amplified signal to a load. A low-pass filter device connects the load to the push-pull field effect transistor devices. The output terminals of the field effect transistor devices are connected in series across a voltage supply which is used to supply the energizing voltages to the transistor devices.
摘要:
A pulse width modulated signal amplifier includes a first input terminal supplied with a rectangular wave signal as a carrier, a second input terminal supplied with a modulating signal, such as an audio signal, an integrator supplied with both the rectangular wave signal and the modulating signal, a high gain amplifier receiving the output of the integrator, a low pass filter receiving the output of the high gain amplifier and producing a demodulated signal corresponding to the modulating signal and which is supplied to an output terminal, and a negative feedback circuit connected between the output of the high gain amplifier and the input of the integrator.
摘要:
A switching circuit with MOS field effect transistors includes a DC voltage source having first and second terminals, first and second MOS field effect transistors each having gate, source, drain electrodes and a substrate, a circuit for connecting the source and drain electrodes of the first and second field MOS effect transistors in push-pull amplifying relation between the first and second terminals of the DC voltage source, a signal input circuit for supplying a signal to drive the gate electrodes of the first and second MOS field effect transistors, an output circuit including an inductor and a load connected in series between the connection point of the first and second MOS field effect transistors and a reference point so that charging and discharging currents of the inductor flow alternately through the source and drain electrodes of each of the first and second MOS field effect transistors when the respective MOS field effect transistors are in their conductive state, and resistors connected between the source electrodes and the substrates of the first and second MOS field effect transistors such that the discharging current of the inductor is prevented from flowing through the respective substrates of the first and second MOS field effect transistors.