Abstract: An outboard motor includes an engine main body, and an intake device to supply air to the engine main body. The intake device includes a main intake pipe including a first intake pipe and a second intake pipe connected to a downstream end of the first intake pipe and extending at an angle with respect to an axial direction of the first intake pipe and through which the air supplied to the engine main body flows, and an extension pipe extending from a connection between the first intake pipe and the second intake pipe and including a resonance chamber therein. The extension pipe includes an extended peripheral wall and an end wall that closes the resonance chamber except for a portion adjacent to the main intake pipe.

Abstract: A control method for AC pulse arc welding performed upon application of cyclic AC welding current is provided. The welding current has a cycle including an electrode negative polarity period and an electrode positive polarity period subsequent to the electrode negative polarity period. In the control method, an electrode negative polarity base current and a subsequent electrode negative polarity peak current are applied during the electrode negative polarity period. The electrode negative polarity base current has an absolute value smaller than a first critical value, and the electrode negative polarity peak current has an absolute value greater than the first critical value. Then, an electrode positive polarity peak current is applied during the electrode positive polarity period. The electrode positive polarity peak current has a value greater than a second critical value.

Abstract: A control method for AC pulse arc welding performed upon application of cyclic AC welding current is provided. The welding current has a cycle including an electrode negative polarity period and an electrode positive polarity period subsequent to the electrode negative polarity period. In the control method, an electrode negative polarity base current and a subsequent electrode negative polarity peak current are applied during the electrode negative polarity period. The electrode negative polarity base current has an absolute value smaller than a first critical value, and the electrode negative polarity peak current has an absolute value greater than the first critical value. Then, an electrode positive polarity peak current is applied during the electrode positive polarity period. The electrode positive polarity peak current has a value greater than a second critical value.

Abstract: An consumable electrode AC pulsed arc welding is performed by repeatedly executing a cycle of supplying a peak current Ip in an electrode positive polarity, then supplying an electrode negative current Ien in an electrode negative polarity and finally supplying a base current Ib in the electrode positive polarity. During a base current supply time, the rate of increase dVb/dt of the base voltage Vb is detected. Should the base voltage increase rate dVb/dt detected be larger than a predetermined determining value &Dgr;Vu, it means that the arc interruption is likely to occur and, therefore, since that timing, the peak current Ip for the subsequent cycle is supplied to thereby prevent the arc interruption from occurring.

Abstract: An arc length controlling method that is used in the practice of the pulsed welding in which welding is carried out by feeding an consumable electrode at a substantially constant speed while the pulse frequency f is set to a predetermined value. This method is carried out by effecting a welding after the counting time Tr and the target short-circuiting frequency Nr have been set, detecting the detected short-circuiting frequency Nk, and controlling the output voltage Vt to a value effective to allow the detected short-circuiting frequency Nk to be equal to the target short-circuiting frequency Nr.

Abstract: In an integrated-circuit capacitive coupling circuit, first and second diodes are slightly forward-biased to develop bias voltages at their cathode terminals. Input voltages are respectively applied through first and second capacitors to the cathode terminals of the diodes. A differential amplifier is formed by first and second transistors having their bases respectively connected to the cathode terminals of the diodes for receiving the bias voltages via the diodes and the input voltages via the capacitors for developing a differential output voltage. A fast charging circuit is additionally connected to the cathode terminals of the first and second diodes to supply charging currents to the capacitors for a short period in response to a control signal.

Abstract: A constant-current source including a constant-current output circuit for supplying a constant current provided with one or more transistors with the bases biased with the same base potential, a first circuit which provides a first current signal for setting the strength of the constant current to be delivered from the constant-current output circuit, a second circuit which generates a second current signal and provides the same base potential in response to the second current signal, a third circuit which controls the second current signal to minimize any deviation of the second current signal from the first current signal, and a DC power supply for energizing at least the first, second and third circuits.