Abstract: In a circuit arrangement for rectifying a signal, in which two transconductors are controllable with opposite phase by means of the signal to be rectified, the outputs of the transconductors are connected to a first circuit point via a first diode and to a second circuit point via a second diode having an opposite polarity with respect to the first diode. The circuit points are connected to a predetermined potential. A rectified signal can be derived from at least one of the circuit points.

Abstract: A semiconductor device includes a differential level converter circuit that receives a first signal and outputs a second signal of greater amplitude. The differential level converter has a first MISFET pair for receiving the first signal, a second MISFET pair for enhancing the withstand voltage of the first MISFET pair, and a third MISFET pair with cross-coupled gates for latching the second signal from output. The film thickness of the gate insulating films of the second and third MISFET pairs is made thicker than that of the first MISFET pair, and the threshold voltages of the first and second MISFET pairs are made smaller than that of the third MISFET pair. This level converter circuit operates at high speed even if there is a large difference in the signal amplitude before and after level conversion.

Abstract: A digital multiplexer circuit includes an input transmission line structure receiving input signals, multiplexing blocks having input terminals that are successively coupled together by the input transmission line structure, and an output transmission line that successively couples output terminals of the multiplexing blocks and receives output signals from multiplexing blocks.

Abstract: A half-bridge circuit including a low-side drive module (110) and a high-side drive module (210) for driving respective lower (T1) and upper (T2) transistors. Each drive module (110, 210) is a charge trap circuit in that the low-side drive module (110) drives the low-side transistor (T1) with the charge on a capacitive load (C), and the high-side drive module (210) alternately recharges the capacitive load (C) as it is driven by a high-voltage supply. Each charge trap circuit (110, 210) also includes a diode (D1, D2) that prevents unintentional loss of charge on a gate of a driven transistor (T1, T2), and a zener diode (Z1, Z2) that clamps the gate voltage at a safe level. In this manner, the half-bridge circuit is efficiently driven without the need of an auxiliary power supply.

Abstract: An apparatus for biasing a body voltage of a silicon-on-insulator transistor includes an operational amplifier that generates an output voltage that is proportional to the voltage difference between a desired gate-source threshold voltage and a reference voltage. A reference biasing transistor has a gate that is electrically coupled to the output. A reference mirror transistor has both a gate and a drain that are electrically coupled to the current source node, and also has a body that is electrically coupled to the drain of the reference biasing transistor. A device biasing transistor has a gate that is electrically coupled to the output voltage and has a drain that is electrically coupled to the body of the silicon-on-insulator transistor. The device biasing transistor maintains a voltage at the body of the silicon-on-insulator transistor so that it has a gate-source threshold voltage within a predetermined range of the desired gate-source threshold voltage.

Abstract: The present invention provides an improved current mirror circuit. For example, in a voltage controlled oscillator of a phased-locked loop circuit, MOS device is used to replace a fixed resistor in the control circuit before the current mirror circuit for controlling the mirror currents of the related MOS devices in the phased-locked loop circuit, and for controlling the operating frequency of the phased-locked loop circuit.

Abstract: A voltage reference circuit is provided, including a plurality of switching elements connected to a reference node, a voltage divider for providing a different voltage to each of the switching elements, and logic circuitry for selectively actuating the switching elements in response to a control signal provided to all of the switching elements.

Abstract: A power supply circuit includes a transistor, a variable resistance circuit, a second resistance, and an operational amplifier. The variable resistance circuit includes a plurality of first resistances. The plurality of first resistances are selected in response to control signals. The selected first resistances are connected in series, the unselected first resistances are connected to a ground voltage. The second resistance is connected between the variable resistance circuit and the ground voltage. The operational amplifier compares the voltage of the other end of the variable resistance circuit with a reference voltage and feeds a signal indicating a comparison result back to the gate of the transistor.

Abstract: A semiconductor integrated circuit includes a plurality of functional blocks, each of which starts and stops an operation thereof in response to assertion and negation, respectively, of a corresponding command signal, a clock generation circuit which generates a clock signal, a clock control circuit which starts supplying the clock signal to each of the functional blocks in response to the assertion of the corresponding command signal, and stops supplying the clock signal to each of the functional blocks in response to the negation of the corresponding command signal.

Abstract: An amplification circuit of the present invention includes a first MOS transistor having a gate to which a first input terminal for inputting a positive logic input signal or a reference potential is connected and a drain to which a first load is connected, a second MOS transistor having a gate to which a second input terminal for inputting a negative logic input signal, which composes differential input signals with the positive logic signal, or the reference potential is connected and a drain to which an output terminal and a second load are connected, and pairing up with the first MOS transistor, and a current source to which sources of the first and second MOS transistors are connected, for supplying a constant current when the difference in voltage between the first and second input terminals is in a predetermined range, and varying the current to be supplied when the difference in voltage is beyond the predetermined range.

Abstract: Methods and devices for demodulators for continuous phase modulation waveforms. A modulated sampled signal is received. A consecutive sequence of the modulated sampled signal is buffered. The consecutive sequence is compared with all possible valid modulated sampled signals. A bit decision representing a demodulation of the consecutive sequence of the modulated sampled signal is determined based on a closest valid modulated sampled signal located closest to the consecutive sequence of the modulated sample signal in a constellation.

Abstract: A method and circuitry for implementing programmable gain. More particularly, embodiments of the present invention provide an amplifier circuit which can be used as a CDS-amp or an instrumentation amplifier. Included is a two-stage amplifier, each stage having a few as one transistor. A current source biases one stage of the two-stage amplifier. A load resistor network couples to the two-stage amplifier and is configured to set gain values for the two-stage amplifier.

Abstract: A modulated signal is connected to a full bridge switching amplifier (16, 18, 28, 30) and is compensated to remove a predetermined frequency and its odd harmonics. The compensation inverts and delays (26) a signal that is connected to a first half of the full bridge and applies the delayed inverted signal to a second half of the full bridge. By delaying by an odd number of half cycles, the carrier and its odd harmonics are cancelled because the same signal exists on both sides of the full bridge output. When these two same signals are subtracted by the full bridge action, the carrier and odd harmonics are suppressed. Spectral nulls may be provided for various signal applications, not just audio, and when various types of modulation techniques are used, such as PWM and PDM.

Abstract: The present invention relates to a radio frequency amplifier and a method of driving the radio frequency amplifier, and an object of the present invention is to provide a radio frequency amplifier and a method of driving the radio frequency amplifier which are excellent in the controllability at the time of a low power output while keeping the advantage of a high efficiency and give the heating generated by a power loss of such a degree that dewing generated due to over-cooling by the cooling system is not generated at the time of a low power output. The radio frequency amplifier is structured by a variable wave height and variable wave width pulse wave generating circuit 11 that generates a pulse wave (rectangular wave) having an arbitrary pulse height and pulse width, and a power amplifier 12 that is driven by the rectangular wave.

Abstract: A predistortion system compensates or equalizes the phase and/or amplitude response over frequency of at least a portion of a signal path prior to the distortion generating circuitry, such as an amplifier, and/or of at least a portion of a feedback path after the distortion generating circuitry. For example, in a power amplification system using predistortion, an equalizer on the signal path adjusts the phase and amplitude of a predistorted signal across frequency to compensate for the amplitude and phase response of circuitry on the signal path, such as the amplitude and phase response of analog filters in the up-conversion process. After amplification, an equalizer on a feedback path adjusts the phase and amplitude across frequency of the signal representing the output of the amplifier to compensate for the amplitude and phase response of circuitry, such as analog filters in the down-conversion process, on the feedback path.

Abstract: A group delay adjusting circuit. The group delay adjusting circuit comprises an electronically adjustable variable capacitance, and an electronically variable virtual inductor coupled in parallel to the electronically variable capacitance at a node.

Abstract: A differential buffer/driver has a switch network that connects an IOH current source to a differential output to be drive high, and connects an IOL current source to the other differential output to be driven low. Each output can be connected to a pull-down boost current sink. A boost pulse momentarily connects a boost current sink to the differential output being driven low. The differential buffer generates a pair of boost pulses to activate the boost current for either differential output. One boost pulse is activated when one differential output is driven low, while the other boost pulse is activated when the other differential output is driven low.

Abstract: A programmable, rail-to-rail, low-voltage, micro-power harmonic-mean class-AB output stage with MOS devices employed in weak inversion is provided. The output stage MOS devices are arranged in the translinear loop, which avoids having a plurality of MOS devices in series between the power supply rails and thus enables low-voltage operation. The MOS devices in the translinear loop are used to implement the harmonic mean function x*y=z*(x+y) where x and y are mirrored to the output and represent the quiescent push and pull currents, respectively. Circuit operational parameters may be varied to suit a variety of different applications. Increasing the supply voltage for given quiescent current will advantageously increase the maximum current load. Increasing the quiescent current for given supply voltage will advantageously lower the distortion of the output stage.

Abstract: An operational amplifier that decreases idling current, widens a voltage output range, and increases load driving capacity. The operational amplifier includes a first output transistor connected to a high potential power supply. A second output transistor is connected between the first output transistor and a low potential power supply. The first and second output transistors generate an output signal at a node between the first output transistor and the second output transistor. An idling current control circuit controls the collector current of the first output transistor in accordance with the base voltage of the second output transistor to control the idling current of the first and second output transistors.

Abstract: A single ended input differential output amplifier (100) and integrated circuit including such an amplifier (100). A pair of load resistors (102, 104) are connected between a supply voltage (Vdd) and differential outputs OUTP and OUTM. An inductor (106) is connected between input RFIN and a source bias voltage VBs. A first field effect transistor (FET) (108) is connected, drain to source, between load resistor (102) at output OUTP and inductor (106) at RFIN. A second FET (110) is connected, drain to source, between the second load resistor (104) at output OUTM and the source bias voltage VBS. A gate bias voltage VBg is connected to the gate of FET (108) and through resistor (112) to the gate of FET (110). A coupling capacitor (114) is connected between the input RFIN and the gate of FET (110).

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: An object of this invention is to provide a phase synchronizing circuit capable of automatically adjusting a VCO such that the VCO satisfies a predetermined frequency range even in a frequency range in which the VCO oscillates by a leak current generated if a low threshold process is applied. The phase synchronizing circuit is composed of a PLL consisting of a phase comparator, a charge pump, a loop filter, a VCO, and a divider, and a calibration circuit for automatically adjusting a frequency range of the VCO. Before a convergence operation is started, a switch is closed in response to a signal Rst of the calibration circuit such that an output of the loop filter is leveled to the ground and the PLL is set to be an open loop. A VCO output Fo is set at an upper limit frequency or a lower limit frequency in response to a Vcal signal, and its frequency is measured by comparing its period with a period of a reference signal Fr, and signals Hb, Lb used for adjusting the frequency of the VCO are updated.

Abstract: A phase-locked loop including an oscillator, controlled by a control signal generated by a comparison circuit comparing a reference frequency and the oscillator frequency and filtered by an integrator low-pass filter; a control and adjustment circuit for, with a predetermined frequency smaller than the reference frequency, taking into account the value of the filtered controlled signal and, if this value is out of a range of predetermined values, adjusting the operating range of the oscillator; and an inhibition circuit for deactivating the comparison circuit for a predetermined duration before taking into account the value of the filtered control signal.

Abstract: A RC oscillator circuit with a stable output frequency, having an oscillating integrated circuit working under an operation voltage, the resistor, a first capacitor, a second capacitor, and a transistor. The first and second capacitors construct a RC circuit. The resistor has first and second terminals coupled to output and input terminals of the oscillating integrated device, respectively. The first capacitor has first and second terminals coupled to the input terminal of the oscillating integrated device and the second terminal of the resistor, respectively. The second capacitor has first and second terminals coupled to the second terminal of the first capacitor and ground, respectively. The transistor has a gate coupled to the operation voltage, a drain coupled to the first terminal of the second capacitor, and a grounded source. The RC oscillator circuit with a modulable frequency can work under difference operation voltages and output the same frequency.

Abstract: The oscillator includes an active device, a substrate, a microstrip line formed on the substrate, and a dielectric block. The resonator is made up with the microstrip line and the dielectric block that is disposed so as to couple with the microstrip line. The active device produces a negative resistance in a desired oscillation frequency band. The dielectric block is set such that a resonance frequency of the lowest order mode of the dielectric block is lower than a desired oscillation frequency, and the resonance frequency of one of the higher order modes coincides with the desired oscillation frequency. The oscillator is generated with the higher order mode of the resonator. Thus, the invention provides at a low cost a millimeter wave band oscillator of a low phase noise by using this oscillator, and a transmitter-receiver module and a radar system applying this oscillator to the local signal generator.

Abstract: A conventional voltage-controlled oscillator, when formed as an integrated circuit, suffers from a low Q factor of its resonant portion and thus poor phase noise characteristics. To overcome this, a voltage-controlled oscillator of the invention has a resonant portion including at least one variable-capacitance device and at least one inductor, an active portion including differential pair transistors and supplying electric power to the resonant portion in such a way as not to attenuate the oscillation of the resonant portion, and a current source connected to the emitters or sources of both of the differential pair transistors. The current source is a circuit having a resistor and a capacitive device connected in parallel.

Abstract: An electromagnetic enclosure is provided that this configured to enclose an electrical assembly. The enclosure includes a waveguide defining a channel that one or more cables from the electrical assembly pass through. The waveguide is dimensioned to attenuate radiation having a selected frequency range. With the present invention, shielding emitted or transmitted radiation around an opening in an enclosure and around cables can be easily done.

Abstract: An advanced electronic signal conditioning circuit and associated housing elements. In one embodiment, the circuit comprises a plurality of coupled inductors and capacitors arranged in a signal filtering configuration which achieves enhanced voice- and DSL-band performance through the use of complex-impedance modeling during the circuit design phase. Free-standing and fixed device housings are also disclosed. Methods for manufacturing the aforementioned components are also described.

Abstract: A component that includes a first structure that is integrated with a second structure. The first structure is a lumped balanced to unbalanced circuit (balun) and the second structure is a resonator-based filter. The function of the balun is to move a signal from a differential form to a single ended form or from a single ended form to a differential form. The component has an area that is comparable to the area needed to implement the balun alone. However, the component now provides a filter function. Preferably, the substrate of the first structure also acts as a substrate for the second structure.

Abstract: On one surface of a dielectric substrate having a thickness of one quarter of a signal wavelength, a ground electrode, and a strip line, one end thereof being connected to a high-frequency element via a wire, are formed. On the opposite surface thereof, which opposes a waveguide, a ground electrode is formed, a first electrode opening having a predetermined length and width is formed, opposite to a proximity of an open end of the strip line, and a second electrode opening is formed so that a center line of a width thereof is separated outward by one quarter of the signal wavelength from a conductor wall of the wave guide. Furthermore, via holes having a length of one quarter of the signal wavelength, electrically connecting the ground electrodes on either surface, are formed. The waveguide is disposed in proximity to the dielectric substrate so that a center of the first electrode opening coincides with that of the waveguide.

Abstract: A high performance diplexer is disclosed having a common conductor which branches into two resonators in distributive form. The diplexer may be used reciprocally, has low insertion loss, is tuneable, has high signal isolation and impedance matching, and may be readily produced to meet the space requirements relating to size, temperature, radiation and performance. A method of tuning the resonators of the diplexer is also disclosed. Specific applications for the diplexer are also disclosed and include use in a GPS transmitter, GPS receiver and as part of an electronic scan array (ESA) antenna. The diplexer's small size and weight, and its resistance to the conditions of space make it ideal for use in satellite applications.

Abstract: A filter structure (900, 1300, 1400, 1610) comprises a filter section (900) having at least two branches (901, 902) connected in parallel. A first branch (901) of said at least two branches comprises a first plurality (921, 701) of piezoelectric resonators connected in series, and a second branch (902) of said at least two branches comprises a second plurality (922, 702) of piezoelectric resonators and phase shifting means (910) connected in series. The phase shifting means are arranged to provide a phase shift of substantially 180 degrees.

Abstract: A dielectric duplexer device is provided with an output terminal pad formed on a side surface of a dielectric block in the vicinity of an open end associated with a plurality of resonators of a reception section in such a manner as to face the resonators. An extension electrode extends from the output terminal pad onto an end face of the dielectric block where the open end is present, to thereby be capacitively coupled with the resonators. The coupling capacitance can be readily corrected by adjusting the position of the end of the extension electrode. In one specific form, when the dielectric duplexer is mounted, the extension electrode is exposed and is also joined to a predetermined conductive path by means of solder. Accordingly, the output terminal pad is soldered at the bottom and side surfaces thereof to thereby be fillet-soldered, thereby providing visibility of electrical and mechanical connections thereof to the predetermined conductive path and thus enhancing the reliability of the mounted state.

Abstract: Air-dielectric sandwich structures for electrically tunable microwave devices provide two types of layered structures; one type comprising a first dielectric material, a second dielectric material, an air gap between the first and second dielectric materials and an electromechanical actuator for adjusting the width of the air gap by moving the first or second dielectric materials, and the other type comprising a dielectric material, a metal wall, an air gap between the dielectric material and the metal wall and an actuator for adjusting the width of the air gap by moving the dielectric material or the metal wall. The tunable microwave devices including the air-dielectric sandwich structure are elaborated such as a tunable dielectric resonator, a band stop and a band pass filter, a phase shifter and a phase array antenna.

Abstract: A leaky surface acoustic wave resonator includes reflectors each having metal fingers on the piezoelectric substrate. The metal fingers have a ration of finger width to finger width plus the width of the space therebetween of from 0.75 to 1.0.

Abstract: A surface acoustic wave filter unit having three interdigital transducers arranged along the surface acoustic wave propagation direction is disposed on a piezoelectric substrate. An unbalanced signal terminal and balanced signal terminals are provided for the surface acoustic wave filter unit. At least one of the three interdigital transducers is out of phase relative to the other interdigital transducers. Reflectors are arranged so as to sandwich the three interdigital transducers therebetween. The reflectors are grounded. Thus, a surface acoustic wave filter having a balance-to-unbalance conversion function and having high balance between the balanced signal terminals is achieved.

Abstract: A TE dual-mode resonator is provided. The TE dual-mode resonator has first and second modes. The resonator includes an enclosure having a cavity with an interior surface. The resonator further includes a dielectric resonator body, having a central portion with a plurality of members extending outwardly from the central portion. The dielectric resonator body is coupled directly to the interior surface.

Abstract: A vertical transition device for differential stripline paths, connects differential microstrip paths on a horizontal plane with differential triplate paths on another horizontal plane in a multilayered architecture. The differential microstrip paths include a pair of differential microstrip lines. The differential triplate paths include a pair of triplate lines. The differential microstrip lines are connected with the differential triplate lines by via-holes within the transition device, respectively.

Abstract: A waveguide assembly including a waveguide, a backshort member, and an adjustment member, where the adjustment member is capable of receiving or input and transforming it into an output that causes the backshort member to be displaced in response to said input.

Abstract: A microrelay device is described including a substrate with a first pair of contacts, a ferromagnetic material and a conductive coil surrounding the ferromagnetic material. The microrelay also includes an actuator having a permanent magnet and a contact area. The actuator is fixed at a first end and movable between a first position and a second position. The contact area of the actuator is spaced from the pair of contacts on the substrate in the first position and in contact with the first pair of contacts on the substrate in the second position. A method of fabricating a microrelay device is also described including forming a conductive coil embedded in an insulating material.

Abstract: A circuit breaker (100) for use between a load and a power source, comprising at least two movable contacts (212/222) for electrical connection to the load and power source respectively, a movable contact holder (220) holding the first contact (222), a first spring (224) biassing the contact holder (220) to move, and an actuator (210) arranged to move the second contact (212) into contact with the first contact (222). A locking frame (230) is arranged to lock the contact holder (220) and in turn the first contact (222) at a specific position into the path of movement of the second contact (212), against the action of the spring (224), for contact by the second contact (212). The locking frame (230) is supported for pivotal movement between a first position locking the contact holder (220) in said specific position and a second position releasing the contact holder (220) from said specific position. A second spring (238) biasses the locking frame (230) towards the second position.

Abstract: A modular magnetic tool system utilizes one or more magnet modules and attachable components to enable selective assembly of a wide variety of magnetic tools. Channels of the magnet modules are connectable in series and in parallel, either by integral connectors or attachable components which can be selectively attached to the magnet modules singularly, in series, or in parallel to form different types of magnetic tools with different functions for different applications.

Abstract: An inductor with multiple air-gap separations comprises a magnetic core and an enameled wire around the magnetic core. The magnetic core has an air gap with at least a large-gap portion and a small-gap portion. The small-gap portion provides enough inductance in case of low load input to prevent harmonic distortion. The large-gap portion provides enough inductance in case of heavy load output and low input voltage to prevent saturation and temperature rise, thus enhancing power efficiency.

Abstract: A choke coil has small difference of wire wound resistances between coils to obtain sufficient unbalance attenuation amount, superior in workability in winding and reduced leakage inductance and line capacity. The choke coil includes first and second coils divided into first and second segments wound on a single spool disposing intermediate insulations layers between respectively adjacent coil segments. The coil segments of the first and second coils are wound alternately. The first coil segment of the first coil and the second coil segment of the second coil being wound in a first winding number and the second coil segment of the second coil and the first coil segment of the second coil being wound in a second winding number. The second winding number being greater than the first winding number for reducing difference of winding resistance between the first and second coils less than or equal to 4%.

Abstract: A yoke of an electromagnetic clutch includes a ring case, a coil assembly, a connector, and at least one contact. The ring case includes an annular groove and an opening. The coil assembly is positioned in the annular groove. The connector is positioned in the opening of the ring-case and includes a first groove to receive an end portion of the coil assembly, a second groove to receive a lead wire of a diode, and a third groove to receive an end portion of an external wire. The at least one contact includes three pairs of slits and may be inserted in the connector so that each of the three pairs of slits is aligned with a respective one of the first groove, the second groove, and the third groove to form an electrical connection between the end portion of the coil assembly, the lead wire of the diode, and the end portion of the external wire.

Abstract: The multiple concentric coil wattage converter is a non-conventional type of concentric, closely wound coil component, that can be applied to either increasing voltage or amperage, or a combination of both, as required by each specific load application.

Abstract: A new structure and method is provided for the creation of an inductor on the surface of a silicon semiconductor substrate. The inductor is of a helix coil design having upper level and lower level conductors further having an axis whereby the axis of the helix coil of the inductor is parallel to the plane of the underlying substrate. Under the first embodiment of the invention, the height of the helix coil that is created on the surface of a silicon substrate is uniform. Under the second embodiment of the invention the height of the helix coil of the inductor of the invention is uniform while a ferromagnetic core is inserted between the upper and the lower level conductors of the helix coil. Under the third embodiment of the invention, the height of the helix coil that is created on the surface of a silicon substrate is non-uniform.

Abstract: An advanced circuit breaker system and method includes first and second terminals to electrically couple the advanced circuit breaker to an electrical circuit. A cam applies a first torque to a rotatable contact arm, having an arm contact electrically coupled to the first terminal, from a first position to a second position of the contact arm and a second torque to the contact arm from the second position to a third position. A bimetal blade, having a blade contact electrically coupled to the second terminal, changes shape when electrical current flowing through it exceeds a threshold for at least a predetermined amount of time. The arm contact maintains contact with the blade contact when the first torque occurs and separates from the blade contact when the second torque occurs. The blade contact changes shape to increase separation from the arm contact if electrical current exceeds at least a certain amount above the threshold.

Abstract: A precipitate film having plating resistance may be formed on the surface of a varistor element during sintering process. Accordingly, the manufacturing process can be shortened, thereby improving the productivity. The manufacturing method comprises (a) a first process of forming the varistor element whose main component is zinc oxide; (b) a second process of sintering the varistor element and precipitating zinc compound having at least one of acid resistance and alkali resistance on the surface of the varistor. Preferably, the manufacturing method further comprises (c) a process of attaching an external electrode to the varistor element, and the external electrode attaching process is executed after finishing the varistor element sintering process.

Abstract: A precipitate film having plating resistance may be formed on the surface of a varistor element during sintering process. Accordingly, the manufacturing process can be shortened, thereby improving the productivity. The manufacturing method comprises (a) a first process of forming the varistor element whose main component is zinc oxide; (b) a second process of sintering the varistor element and precipitating zinc compound having at least one of acid resistance and alkali resistance on the surface of the varistor. Preferably, the manufacturing method further comprises (c) a process of attaching an external electrode to the varistor element, and the external electrode attaching process is executed after finishing the varistor element sintering process.