US3764951A - Non-linear resistors - Google Patents

Non-linear resistors Download PDF

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Publication number
US3764951A
US3764951A US00327175A US3764951DA US3764951A US 3764951 A US3764951 A US 3764951A US 00327175 A US00327175 A US 00327175A US 3764951D A US3764951D A US 3764951DA US 3764951 A US3764951 A US 3764951A
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United States
Prior art keywords
sintered
oxide
superposed
wafers
weight percent
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Expired - Lifetime
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US00327175A
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English (en)
Inventor
M Ono
K Tachibana
M Nishioka
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Mitsubishi Mining and Cement Co Ltd
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Mitsubishi Mining and Cement Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/105—Varistor cores
    • H01C7/108—Metal oxide
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49082—Resistor making

Definitions

  • ABSTRACT New non-linear resistors having a remarkably stable volt-ampere characteristic are provided.
  • Such resistors comprise several sintered wafers superposed, said sintered wafer consisting of iron oxide as the main component and the respective prescribed quantities of calcium oxide, rare earth oxide and the like, and electrodes applied to opposite surfaces of said several sintered wafers superposed and are based on utilization of the property of the contact surfaces between said several sintered wafers superposed.
  • This invention relates to economical non-linear resistors having a remarkably stable volt-ampere charecteristic manufactured by superposing several sintered wafers, each sintered wafer comprising, as the main component, iron oxide which contains calcium oxide, rare earth oxide, etc. and has resistance of about or not more than [K0, and also small thermal negative resistance, and applying electrodes to opposite surfaces of the several sintered wafers superposed.
  • non-linear resistors (the term nonlinear resistor is referred to as varistor” hereinafter) comprise silicon carbide varistors, silicon varistors, barium titanate varistors and the like.
  • Equation (1) The volt-ampere characteristic of such a varistor is generally given by the following Equation (1):
  • I is the current flowing through the varistor
  • V is the voltage accross the varistor
  • exponent a an index representing non-linearity is a numerical value greater than I, usually 3-5.
  • Silicon varistors and barium titanate varistors are limited in used because their V, values are both only 0.5-l.2V, while silicon carbide varistors have large a above 30V, but small a under 30V. Moreover, in such varistors based on utilization of the mutual contact between internal particles of sintered bodies as silicon carbide varistors, it is difficult to completely control the state of said mutual contact between the internal particles even under the same manufacturing conditions, consequently the products are inevitably variable in the characteristics.
  • This invention has been devised to overcome the defects of the conventional varistors as described hereinabove.
  • a primary object of this invention is to provide a varistor which has a remarkably stable volt-ampere characteristic.
  • Another object of this invention is to provide a varistor which is inexpensive in cost.
  • a nonlinear resistor comprising several sintered wafers superposed, said sintered wafer consisting of iron oxide as the main component, 0.] -34 weight percent of calcium oxide and 0.1-34 weight percent of rare earth oxide, and electrodes applied to opposite surfaces of said several sintered wafers superposed.
  • the sintered wafer may also comprise iron oxide as the main component, O.1-34 weight percent of calcium oxide (CaO), 0.1 -34 weight percent of rare earth oxide and 0.1 weight percent of at least one oxide selected from the group comprising aluminum oxide (A1 0 zirconium oxide (ZrO and cobalt oxide (C00).
  • iron oxide as the main component, O.1-34 weight percent of calcium oxide (CaO), 0.1 -34 weight percent of rare earth oxide and 0.1 weight percent of at least one oxide selected from the group comprising aluminum oxide (A1 0 zirconium oxide (ZrO and cobalt oxide (C00).
  • FIG. 1 is a sectional view of an embodiment of this invention, a non-linear resistor manufactured by superposing two sintered wafers, each sintered wafer comprising iron oxide as the main component.
  • FIG. 2 shows the volt-ampere characteristic of the non-linear resistor of FIG. 1.
  • This invention provides for, example, a non-linear resistor manufactured, as shown in FIG. 1, by superposing two sintered wafers 1, I, each sintered wafer obtained by sintering a molded material comprising iron oxide as the main component and the respective prescribed quantities of calcium oxide (CaO) and rare earth oxide, or a molded material comprising iron oxide as the main component and the respective prescribed quantities of calcium oxide (CaO), rare earth oxide and at least one oxide selected from the group consisting of aluminum oxide (A1 0 zirconium oxide (ZrO and cobalt oxide (CaO), applying electrodes for example silver electrodes 2, 2 to the opposite surfaces of the two sintered wafers superposed respectively, attaching lead wires 5, 5 to the silver electrodes 2, 2 by using solder 4 and fixing the whole with suitable insulating coating material 6.
  • A1 0 zirconium oxide ZrO and cobalt oxide (CaO)
  • the wafer 1 is a sintered plate having any one of various shapes such as circular, square, rechtangular, etc.
  • non-linear resistor of this invention shows both very stable V, and or, especially V of a little less than 20V, it proves to have an aptitude for a varistor. Such stable V and a also makes the yield rate of the product to be improved greatly.
  • the non-linear resistor of this invention utilizes iron oxide as the main raw material, it is also advantageous in cost.
  • This invention also provides non-linear resistors manufactured by superposing more than three plates of said sintered wafer and applying electrodes to opposite surfaces of said sintered wafers superposed respectively.
  • the thus manufactured resistors also have remarkably stable volt-ampere characteristics, proving to be suitable for a varistor.
  • This invention provides varistors having remarkably more stable characteristics at much higher yield rate and at quite lower cost, as compared with the conventional varistors, consequently it is industrially of great value.
  • EXAMPLE 1 The sintered body is prepared by a conventional technique.
  • the starting material in the composition defined inTable l is respectively mixed in a pot mill so as to produce a homogeneous mixture.
  • the mixture is dried in a dryer, pressed in a mold at a pressure of about l ,000kg/cm into a disc of 15mm in diameter and 2mm in thickness.
  • The'molded disc is sintered in air at above 1,200 C, thus the sintered disc 1 is obtained.
  • Example 1 shows that 5 wt percent of La o is required to make a up to 5.
  • Example 2 is carried out.
  • the starting materials in Example 2 are l e O containing 'l5wt percent of CaO and 0.lwt percent of La o added with 0.l-l0wt percent of at least one oxide selected from the group consisting of M 0 ZrO and C00 as shown in Table 2.
  • the starting material is respectively processed and sintered in the same manner as Example 1, thus the sintered disc is obtained respectively.
  • a non-linear resis-- tor is manufactured by using said sintered disc in the same manner as Example 1.
  • the measured values of R, a, V of the thus manufactured varistors are shown in Table 3.
  • Table 4 shows that varistors of good quality having different V, values can be manufactured by superposing more than three plates of such sintered bodies as shown in Table 3.
  • a non-linear resistor comprising several sintered wafers superposed, said sintered wafer consisting of iron oxide as the main component, 0.1 -34 weight percent of calcium oxide (CaO) and 0.l-34 weight percent of rare earth oxide, and electrodes applied to opposite surfaces of said several sintered wafers superposed respectively,
  • CaO calcium oxide
  • ZrO zirconium oxide
  • C00 cobalt oxide

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
US00327175A 1972-02-16 1973-01-26 Non-linear resistors Expired - Lifetime US3764951A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47016303A JPS52556B2 (de) 1972-02-16 1972-02-16

Publications (1)

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US3764951A true US3764951A (en) 1973-10-09

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US00327175A Expired - Lifetime US3764951A (en) 1972-02-16 1973-01-26 Non-linear resistors

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US (1) US3764951A (de)
JP (1) JPS52556B2 (de)
DE (1) DE2307321C3 (de)
FR (1) FR2172133B1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924148A (en) * 1972-11-15 1975-12-02 Mitsubishi Mining & Cement Co Small size DC motors
US4272754A (en) * 1979-12-17 1981-06-09 General Electric Company Thin film varistor
US4290041A (en) * 1978-02-10 1981-09-15 Nippon Electric Co., Ltd. Voltage dependent nonlinear resistor
US4371860A (en) * 1979-06-18 1983-02-01 General Electric Company Solderable varistor
US4706060A (en) * 1986-09-26 1987-11-10 General Electric Company Surface mount varistor
US20040155750A1 (en) * 2003-02-10 2004-08-12 Kazutaka Nakamura Voltage-dependent resistor and method of manufacturing the same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496512A (en) * 1966-05-16 1970-02-17 Matsushita Electric Ind Co Ltd Non-linear resistors
US3632528A (en) * 1968-10-22 1972-01-04 Matsushita Electric Ind Co Ltd Lead-modified zinc oxide voltage variable resistor
US3682841A (en) * 1970-12-01 1972-08-08 Matsushita Electric Ind Co Ltd Voltage dependent resistors in a bulk type

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB579994A (en) * 1944-02-25 1946-08-22 Colin Henry William Clark Improvements in or relating to electric potential sensitive resistances
US3150342A (en) * 1960-02-10 1964-09-22 Morganite Resistors Ltd Non-linear resistors

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496512A (en) * 1966-05-16 1970-02-17 Matsushita Electric Ind Co Ltd Non-linear resistors
US3632528A (en) * 1968-10-22 1972-01-04 Matsushita Electric Ind Co Ltd Lead-modified zinc oxide voltage variable resistor
US3682841A (en) * 1970-12-01 1972-08-08 Matsushita Electric Ind Co Ltd Voltage dependent resistors in a bulk type

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3924148A (en) * 1972-11-15 1975-12-02 Mitsubishi Mining & Cement Co Small size DC motors
US4290041A (en) * 1978-02-10 1981-09-15 Nippon Electric Co., Ltd. Voltage dependent nonlinear resistor
US4371860A (en) * 1979-06-18 1983-02-01 General Electric Company Solderable varistor
US4272754A (en) * 1979-12-17 1981-06-09 General Electric Company Thin film varistor
US4706060A (en) * 1986-09-26 1987-11-10 General Electric Company Surface mount varistor
US20040155750A1 (en) * 2003-02-10 2004-08-12 Kazutaka Nakamura Voltage-dependent resistor and method of manufacturing the same
US7015787B2 (en) * 2003-02-10 2006-03-21 Murata Manufacturing Co., Ltd. Voltage-dependent resistor and method of manufacturing the same

Also Published As

Publication number Publication date
FR2172133A1 (de) 1973-09-28
DE2307321C3 (de) 1978-09-07
DE2307321A1 (de) 1973-09-06
JPS52556B2 (de) 1977-01-08
JPS4886091A (de) 1973-11-14
FR2172133B1 (de) 1979-01-12
DE2307321B2 (de) 1977-12-15

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