US2407288A - Resistor device - Google Patents

Resistor device Download PDF

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Publication number
US2407288A
US2407288A US390286A US39028641A US2407288A US 2407288 A US2407288 A US 2407288A US 390286 A US390286 A US 390286A US 39028641 A US39028641 A US 39028641A US 2407288 A US2407288 A US 2407288A
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US
United States
Prior art keywords
tube
thermistor
resistance
bead
leads
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US390286A
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English (en)
Inventor
Joseph J Kleimack
Gerald L Pearson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US390286A priority Critical patent/US2407288A/en
Priority to GB7834/46A priority patent/GB615988A/en
Application granted granted Critical
Publication of US2407288A publication Critical patent/US2407288A/en
Priority to BE471922D priority patent/BE471922A/xx
Priority to FR944647D priority patent/FR944647A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01C7/04—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 having negative temperature coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/08—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B11/00—Generation of oscillations using a shock-excited tuned circuit
    • H03B11/02—Generation of oscillations using a shock-excited tuned circuit excited by spark
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C5/00—Amplitude modulation and angle modulation produced simultaneously or at will by the same modulating signal

Definitions

  • thermistor The type of resistor to which the present invention applies has been called a thermistor. This term is a contraction of the words thermal resistor and has been applied to a resistor, the. resistance of which varies greatly with changes in temperature.
  • One object of this invention is. a thermistor device having its elements so constructed and. arranged that the resistance of said device will closely follow changes in applied power.
  • Fig. 1 is a sectional view of one illustrative embodiment of the invention
  • Fig. 2 is a sectional view of another illustrative embodiment of the invention.
  • Fig. 3 is an enlarged fractional portion of Fig. 2 to show details
  • Fig. 4 is an enlarged fractional section showing details of still another modification of the invention.
  • Fig. 5 is a section taken on line 5--5 of Fig. 4.
  • Fig. 6 is a plot showing the electrical characteristics of a thermistor device.
  • I0 is a thermistor element in the form of a bead having leads II and I2 embedded therein.
  • A- satisfactory lead material is platinum.
  • the bead may be made of any suitable conducting material having a high resistance-temperature coefiicient-
  • One suitable material consists of a mixture of per cent M11203 and 10 per cent NiO, heat treated at about 1300 centigrade in oxygen.
  • the resistance of the bead may be controlled by varying the percentage of these oxide components, by adding other orides such as those of cobalt or copper, or by employing other oxides or oxide combinations.
  • the leads i I and [2 project respectively from opposite sides of the bead.
  • the bead is inserted in the thin walled tube is of insulating material such as glass, adjacent one end, with lead [2 projecting from said end.
  • Lead Il may be made long enough to project from the other end of the tube. or a conductor It may be secured to the end of lead I l as by Welding.
  • One advantage of using the additional conductor 13 is that it may be made; of a material having a thermal expansion coeflicient approximating that of the glass or other insulating material used to enclose the bead. An alloy of copper, nickel and iron in, proper proportions is suitable when a glass tube is used.
  • the tube is sealed around the bead l0 and in intimate contact therewith. If the tube I4 is of glass, the sealing may be done by the application of sufiicient heat to soften the glass. The other end of the tube is sealed around lead I l or conductor [3 depending on which is employed.
  • An insulating closure or plug l5 for receptacle It supports the thermistor-lead assembly, con.-
  • the receptacle l6 may be a glass vial.
  • a suitable material for this purpose is mercury.
  • FIG. 1 The embodiment of the invention shown in Figs, 2 and 3 is similar to that shown in Fig. 1.
  • An assembly of a bead H3, leads H and I2, conductor l3 and tube M has, in addition, a thin 7 otherwise suitably secured thereto.
  • a block 30 of metal such as copper, comprises the body having high thermal capacity and conductivity.
  • the thermistor-lead assembly is secured within a cavity 3
  • a metallic binding material 32 are a low melting point alloy, such as Woods metal, or other similar bismuth alloys, or a mercury alloy, such as dental amalam. If a low melting point alloy is used, the cavity 3! is filled with the alloy, the assembly inserted and held in place until the alloy solidifies. When employing amalgam, the assembly is inserted in cavity 3
  • a conductor [1 may be suitably secured to the block 30 as by soldering in an orifice in said block.
  • a thermistor having more than two connecting leads or electrodes is desirable.
  • a thermistor-lead assembly suitable for such a device is shown in Figs. 4 and 5. This assembly is similar to those previously described but includes in addition another thermistor lead i9 which may have a conductor 29. welded or As may be seen in Fi 4, the seals at the ends of the tube M support the leads and attached conductors in spaced relation.
  • the three leads H, I?” and i9 may be spaced as indicated in Fig. Although. three leads are shown in Figs. 4 and 5, additional leads may be employed a similar manner where necessary.
  • the materials so far disclosed as suitable for rapidly carrying heat away from the thermistor body are all electrical conductors. Since electrical and heat conduction generally go hand in hand. such materials are particularly suitable for this purpose. However, insulating materials having relatively high heat capacity and conductivity may also be employed.
  • the colostrum tion of the devices may be modified by omission of the insulating layer on the thermistor and leads. In such devices it will, of course, be necessary to bring out all of the leads through this insulating material.
  • fluent insulating material such as alcohol, glycerin, oil or a mixture of oil and sand could be used.
  • Various self-sustaining insulat-- ing materials having reasonably high heat conductivity may be employed for the Fig. 2 type of device. Some such materials are aluminum oxide; a silicon, zircon, phosphoric acid compost tion and like materials.
  • a negative resistance-temperature coeflicient thermistor is subjected to a direct current of increasing magnitude, the voltage drop across it is found to increase to a maximum and then decrease.
  • the static voltage-current curve of a typical thermistor is shown in Fig. 6. Dynamically, the alternating current resistance is negative in the region beyond the voltage maximum Em for sufficiently low frequencies. The dynamic characteristics of a thermistor are shown for several frequencies in Fi 6. If a direct current of value It) greater than I0 (that current corresponding to Em) be applied to the thermistor, a superposed alternating current of frequency approaching zero will trace out a curve aob approximating the static characteristic.
  • the superposed current has a very high frequency, the thermal lag of the thermistor will prevent any change in temperature, and hence in resistance, from taking place.
  • the voltage current trace therefore, will be along the ohmic resistance line cod.
  • the superimposed current will produce traces as shown at e, f and g in the order of increasing frequencies.
  • the eifective alternating current resistance is negative, at high frequencies it is positive and at intermediate frequencies it may be either positive or negative; thus for some critical frequency it becomes equal to zero. This latter is the maximum frequency at which the thermistor can be made to act as an oscillator.
  • the thermistor has a positive resistance-temperature coefficient its characteristic may be illustrated by a current-voltage curve similar to the voltage-current curve of Fig. 5. Such a curve will have a current maximum similar to the voltage maximum Em of Fig. 6.
  • a thermistor the temperature of which will increase and decrease with suffici nt rapidity to follow currents varying at audio frequency, has
  • the temperature will increase rapidly if (1) the increase in current or power is large, (2) the thermal capacity is small, and (3) the rate at which heat can get away from the thermistor is small.
  • a thermistor comprising a relatively small body of thermistor material having a pair of leads embedded therein and mounted in an evacuated vessel will satisfy the first five conditions but the sixth condition is not satisfied and consequently the thermistor does not cool rapidly enough when the power is decreased.
  • the speed of this thermistor can be increased by covering the thermistor body with a of material having high heat conductivity and large heat capacity, as is pointed out in the description of the devices illustrative of this invention.
  • a resistor having a declining voltage-current characteristic comprising a small bead of high negative resistance-temperature coefficient material, having a plurality of electrically conductive leads embedded therein, a tube of glass enclosing said leads and sealed around said bead, a container, a closure for said container, said closure supporting said glass tube Within the container, and a body of mercury in said container and surrounding the glass tube.
  • a resistor having a declining voltage-current characteristic and comprising a small bead of high negative resistance-temperature coefficient material, having plurality of electrically conductive leads embedded therein, a tube of glass having one end thereof sealed around said bead, one of said leads projecting outside of said tube through the glass seal and the others enclosed in said tube and projecting from the other end thereof, a container, a closure for said container, said closure supporting said glass tube within the container, and a body of mercury in said container and surrounding the glass tube, said one lead being in contact With said mercury and a conductor secured through said closure and making contact with the mercury.
  • a resistor having a declining voltage-current characteristic comprising a small body of negative resistance-temperature coefiicient material sealed in one end of a tube of insulating material, a plurality of electrical conductors secured to said body, one of said conductors projecting from the sealed end of the tube and the others extending through said tube and projecting from the opposite end thereof, a layer of metal on the sealed end of said tube, a body of metal having high thermal conductivity and large thermal capacity having a cavity contain ing the previously named elements, and a mass of metallic binding material filling the remainder of the cavity and securing said elements in place Within said metal body, said one conductor being in electrical connection with said metal body and said other conductors and tube projecting from said metal body.
  • a resistor device comprising a small body of material having a high temperature coefilcient of resistance, a plurality of electrically conductive leads embedded in said body and projecting therefrom, a tube of insulating material enclosing said body and a portion of each of said leads, the remaining portion of each lead projecting from the tube to serve as electrical connectors from said body to an external circuit, said tube being sealed around said body and the adjacent portion of said leads, and a mass of high thermal conductivity, large thermal capacity material enclosing and in intimate thermal contact with the major portion of said tube including the part containing said body.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
US390286A 1941-04-25 1941-04-25 Resistor device Expired - Lifetime US2407288A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US390286A US2407288A (en) 1941-04-25 1941-04-25 Resistor device
GB7834/46A GB615988A (en) 1941-04-25 1946-03-13 Improvements in electrical resistor devices or thermistors
BE471922D BE471922A (enrdf_load_stackoverflow) 1941-04-25 1947-03-18
FR944647D FR944647A (fr) 1941-04-25 1947-04-02 Perfectionnements aux resistors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US390286A US2407288A (en) 1941-04-25 1941-04-25 Resistor device

Publications (1)

Publication Number Publication Date
US2407288A true US2407288A (en) 1946-09-10

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Application Number Title Priority Date Filing Date
US390286A Expired - Lifetime US2407288A (en) 1941-04-25 1941-04-25 Resistor device

Country Status (3)

Country Link
US (1) US2407288A (enrdf_load_stackoverflow)
BE (1) BE471922A (enrdf_load_stackoverflow)
FR (1) FR944647A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540600A (en) * 1945-12-29 1951-02-06 Asea Ab Means for generating or influencing an alternating current
US2816997A (en) * 1955-02-23 1957-12-17 Waters Corp Resistance thermometer
US3016506A (en) * 1960-02-01 1962-01-09 Specialties Dev Corp Semi-conductive element
US3024435A (en) * 1960-02-03 1962-03-06 Specialties Dev Corp Semi-conductive element
US3381253A (en) * 1966-03-04 1968-04-30 Victory Engineering Corp High speed wide range surface sensor thermistor
US3479631A (en) * 1965-12-22 1969-11-18 Owens Illinois Inc Thermistors
US3789191A (en) * 1972-09-01 1974-01-29 Ppg Industries Inc Temperature sensor
US4280508A (en) * 1979-12-27 1981-07-28 Barrada M Ismail Method for positioning a fluid withdrawing means by detecting local temperature

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540600A (en) * 1945-12-29 1951-02-06 Asea Ab Means for generating or influencing an alternating current
US2816997A (en) * 1955-02-23 1957-12-17 Waters Corp Resistance thermometer
US3016506A (en) * 1960-02-01 1962-01-09 Specialties Dev Corp Semi-conductive element
US3024435A (en) * 1960-02-03 1962-03-06 Specialties Dev Corp Semi-conductive element
US3479631A (en) * 1965-12-22 1969-11-18 Owens Illinois Inc Thermistors
US3381253A (en) * 1966-03-04 1968-04-30 Victory Engineering Corp High speed wide range surface sensor thermistor
US3789191A (en) * 1972-09-01 1974-01-29 Ppg Industries Inc Temperature sensor
US4280508A (en) * 1979-12-27 1981-07-28 Barrada M Ismail Method for positioning a fluid withdrawing means by detecting local temperature

Also Published As

Publication number Publication date
BE471922A (enrdf_load_stackoverflow) 1947-04-30
FR944647A (fr) 1949-04-11

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