CA1189156A - Mechanically coupled electrical isolator including output stabilization - Google Patents
Mechanically coupled electrical isolator including output stabilizationInfo
- Publication number
- CA1189156A CA1189156A CA000414821A CA414821A CA1189156A CA 1189156 A CA1189156 A CA 1189156A CA 000414821 A CA000414821 A CA 000414821A CA 414821 A CA414821 A CA 414821A CA 1189156 A CA1189156 A CA 1189156A
- Authority
- CA
- Canada
- Prior art keywords
- conductive areas
- amplifier
- type electrical
- electrostatic type
- output
- 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
Links
- 230000006641 stabilisation Effects 0.000 title abstract 2
- 238000011105 stabilization Methods 0.000 title abstract 2
- 230000008878 coupling Effects 0.000 claims description 7
- 238000010168 coupling process Methods 0.000 claims description 7
- 238000005859 coupling reaction Methods 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 229920000131 polyvinylidene Polymers 0.000 claims 2
- 229920000642 polymer Polymers 0.000 abstract description 13
- 239000011888 foil Substances 0.000 description 16
- 230000000452 restraining effect Effects 0.000 description 8
- 239000004020 conductor Substances 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229920006254 polymer film Polymers 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/56—Monolithic crystal filters
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/40—Piezoelectric or electrostrictive devices with electrical input and electrical output, e.g. functioning as transformers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
TITLE
MECHANICALLY COUPLED ELECTRICAL ISOLATOR
INCLUDING OUTPUT STABILIZATION
ABSTRACT OF THE DISCLOSURE
An electrical isolator utilizing the piezo-electric qualities of a polymer lamina having a first driving pair of electrodes, a second pickup pair of electrodes and a third sensing pair of electrodes.
The third pair of electrodes is connected back to control a driving amplifier to cause it to maintain a constant output or driving level thereby compen-sating for changes in the characteristic of the polymer lamina.
MECHANICALLY COUPLED ELECTRICAL ISOLATOR
INCLUDING OUTPUT STABILIZATION
ABSTRACT OF THE DISCLOSURE
An electrical isolator utilizing the piezo-electric qualities of a polymer lamina having a first driving pair of electrodes, a second pickup pair of electrodes and a third sensing pair of electrodes.
The third pair of electrodes is connected back to control a driving amplifier to cause it to maintain a constant output or driving level thereby compen-sating for changes in the characteristic of the polymer lamina.
Description
~ AC~GROUND OF THE INVENTION
Field of the Invention:
______ he present invention relates to ele~trical isolakors and more specifically to a mechanically coupled electrical isolator including an arrangement.
f or compens at i ng for the electrical variations re-sulting f rom changes in the E~roper~ies Gf the iso-lating film.
u _ A~t:
Isolation of two electrical cirs~uits re-quires the transEer of power and/or information through a means other than that of electric current~
Isolators exist using/ for example: magnetic radiation (radio), light (optocouplers).
Piezoelectric polymer films~ such as poly-vinylidene fluoride, can be used to transduce appliedelectrical signals into mechanical strain within that film. The process is revercible hence mechanical strain can be converted into electrical signals.
Mechanical strain is thereEore a further means for use in an isolator of electrical circuits.
Polyvinylidene Fluoride (PVDF or PVF23 is a polymer which has excellent piezoelectric properties~
I1owever the pie~oelectric 'constants' of the material have been observed to vary over the range of tempera-ture associated with human environments (see WO D~
Cragg and N. W~ Tester/ "Telephone Transducers using Piezoelectric Polymer ~oil" t Eleckrical Communication~
No~ 52 1977) and these variations are repeatable provided tha~ a certain maximum temperature is not exceeded. Above such a maximum the change in sensi-tivity becomes irreversible and time dependent (see J. M. Powers, "Effects of Temperature on the Aging Rate of Piezoelectric Polymer"~ presented at the 94th meeting of the Acoustical Society of America, 1977).
Field of the Invention:
______ he present invention relates to ele~trical isolakors and more specifically to a mechanically coupled electrical isolator including an arrangement.
f or compens at i ng for the electrical variations re-sulting f rom changes in the E~roper~ies Gf the iso-lating film.
u _ A~t:
Isolation of two electrical cirs~uits re-quires the transEer of power and/or information through a means other than that of electric current~
Isolators exist using/ for example: magnetic radiation (radio), light (optocouplers).
Piezoelectric polymer films~ such as poly-vinylidene fluoride, can be used to transduce appliedelectrical signals into mechanical strain within that film. The process is revercible hence mechanical strain can be converted into electrical signals.
Mechanical strain is thereEore a further means for use in an isolator of electrical circuits.
Polyvinylidene Fluoride (PVDF or PVF23 is a polymer which has excellent piezoelectric properties~
I1owever the pie~oelectric 'constants' of the material have been observed to vary over the range of tempera-ture associated with human environments (see WO D~
Cragg and N. W~ Tester/ "Telephone Transducers using Piezoelectric Polymer ~oil" t Eleckrical Communication~
No~ 52 1977) and these variations are repeatable provided tha~ a certain maximum temperature is not exceeded. Above such a maximum the change in sensi-tivity becomes irreversible and time dependent (see J. M. Powers, "Effects of Temperature on the Aging Rate of Piezoelectric Polymer"~ presented at the 94th meeting of the Acoustical Society of America, 1977).
2 5 SUMMARY OF T~IE INVENTION
~he present invention concerns a technique for the construction of an inexpensive piezoelectric polymer film isolator. The piezoelectric coupling fil~ is fixed at two or more discrete places 90 as to define the length of the coupling means and stressed to ensure -the presence of a static strain within the coupling film. The film has on opposite surfaces thereof specific patterns of conductive material.
The conductive material forming two or more discrete active elements of -the isolator. ~he conductive material o~ the pa-ttern also forms the electrical connecting means to the active elementsO ~ first pair of the active elements is connected to an electronic circuit for applying an electrical signal theretol and a second of pair of the active elements is asso-ciated with a second electronic circuit for picking up the signal induced in the second pair oE active 5 elements. The second electronic circuit is not con-nected to said first electronic circuit except through the mechanical coupling of said film. A third pair of active elements is connected back to the electronic circuit driving the first pair of active elements -to vary its amplification in accordance with the signal picked up by the elements.
DESCRIPTION OF THE DRAWINGS
Fig~ 1 is a vlew in perspective showing the piezoelectric polymer foil with the conductive areas thereon.
Fig. 2 is a plane view also showing the piezoelectric polymer foil and the relative placement of the conductive areas.
Fig. 3 is a perspective view showing the placement of a strain inducing member.
Fig. 4 i~ a circuit drawing showing how the invention may be interconnected electrically~
Referring to Fig. l; there is shown a side view of a piezoelectric polymer lamina 1, a first restraining means 2, and a second restraining means
~he present invention concerns a technique for the construction of an inexpensive piezoelectric polymer film isolator. The piezoelectric coupling fil~ is fixed at two or more discrete places 90 as to define the length of the coupling means and stressed to ensure -the presence of a static strain within the coupling film. The film has on opposite surfaces thereof specific patterns of conductive material.
The conductive material forming two or more discrete active elements of -the isolator. ~he conductive material o~ the pa-ttern also forms the electrical connecting means to the active elementsO ~ first pair of the active elements is connected to an electronic circuit for applying an electrical signal theretol and a second of pair of the active elements is asso-ciated with a second electronic circuit for picking up the signal induced in the second pair oE active 5 elements. The second electronic circuit is not con-nected to said first electronic circuit except through the mechanical coupling of said film. A third pair of active elements is connected back to the electronic circuit driving the first pair of active elements -to vary its amplification in accordance with the signal picked up by the elements.
DESCRIPTION OF THE DRAWINGS
Fig~ 1 is a vlew in perspective showing the piezoelectric polymer foil with the conductive areas thereon.
Fig. 2 is a plane view also showing the piezoelectric polymer foil and the relative placement of the conductive areas.
Fig. 3 is a perspective view showing the placement of a strain inducing member.
Fig. 4 i~ a circuit drawing showing how the invention may be interconnected electrically~
Referring to Fig. l; there is shown a side view of a piezoelectric polymer lamina 1, a first restraining means 2, and a second restraining means
3 arranged such that both of these means combine to ensure that the lamina 1 is fixed in length between the restraining points 4 and 5O The piezoelectric polymer may be of polyvinilidene fluoride. Cavities 6 and 7 between the polymer lamina 1 and the restrain-ing means 2 and 3 are preferably enclosed to protect the Eoil from external acoustic signals. Areas 8 and 8' are :Layers o conducting material (for example, aluminum), 9 and 9' as well as 10 and 10' are also similar areas of conducting material not connected with either 8 or 8' or each other. Each pair o conduct-ing areas constitutes an active element where these areas overlap.
, :
The application oE an electrical signal between any pair of conducting areas such as the conducting areas 8 and 8l; will cause a strain in the polymer foil due to the piezoelectric properties oE that foil. This strain is present at any part oE the foil between the restraining points 4 and 5;
hence, due to the piezoelectric properties of that foil~ an electrical signal will be produced at each oE
pairs of similar conducting areas 9 and 9' and 10 and 10'.
Fig. 2 shows in a plane v1ew the conducting areas in relation to the surface of the foil.
Referring to Fig. 2; 1 is the piezoelectric polymer foil, 4 and S the restraining points, 11 and 11' are optional holes to as~ist the mechanical and acoustic protection of the active part of the foil, 12 and 12' are the connecting means to the conducting areas 8 and 8', similarly 13 and 13' and 14 and 14' are the connecting means to the conducting areas to 10 and 10l and 9 and 9I respectively.
To ensure that either polarity oE super-imposed strain, resulting from either polarity of electrical signal, can be achieved within ~he foil it must be in a state oE strainu The absence of static pressure would only permit the existance of superimposed tensile strain.
The stakic pressure can be provided by deforming the foil after it has been clamped at the restraining points either by a rigld form 15 as shown in Fig. 3 or by a resilient form; the latter type will result in an acoustic coupling between the active elements in addition to the mechanical coupling be-tween the active elements on the foil and exagerate the need to protect the Eoil Erom external acoustic signals if such protection is necessary for a specific application of the isolator. A rigid form should preferably be as shown in Fig. 3 where 15 is a pro-jection of restraining means 3 so as to stretch the foil 1 to a length 4~15~5 which is longer than the length 4-5. All active element.s are provided on the part of the foil lying between 4 and 15.
The strain in the oil between the restrain-s ing points 4 and 5 is experienced equally by the active elements formed by the areas 9/9' and lO/10';
the electrical signal produced at each of these active elements shoul_ therefore be equalO The source im-pedance of the active elemenl:s 9/9' and 10/lO' depends on the area of these elements and the actual electrical signals ~voltages) are thus dependent on tlle impedance of the electrical circuits connected to those elements;
given that the actual areas are inversely proportional to the actual impedances of the connected circuits then the actual voltages will be equal~
It is not necessary for the areas o any of the active elements to be equal; hence these areas -and their shapes - in a particular implementation can be chosen to optimize the physical separation of the conducting areas so as to achieve the electrical isolation required for a particular application.
Fig. 4 shows an electrical application of the strain coupled mechanical system described in Figs. 1 thru 3. The piezoelectric film is shown as a dashed line betwPen the active elements 8 and 8', 9 and 9' and 10 and 10'. These elements are each shown with the primed element connected to a co~mon ground potential, separate grounds being shown for each side of the isolator. The input or driving elements 8 and 8 t are connected to the output of the input amplifier 16. The input signal is applied at the terminals labeled Vin through a network of resistors Rl and R2 and the input ground to the non~inverting input terminal. The sensed piezoelectric generated signal at the active elements lO and 10' is connected back to the inverting input of the amplifier. The signal from the driving elements 8 and 8' via the network composed of resistors R3 and R4 in the series - ~ -path and capacitor Cl connected to ground from the resistors junction point --- is also connected to the inverting input of the amplifier 16 so as to ensure the correct bias to that ampliier; the capacito~
Cl eEfectively bypasses the variations in output voltage to ground so that the feedback to the amplifier is only of the voltage produced at elements lO/lO'.
The isolated output is taken from the active elements 9 and 9' to an output amplifier 17. This amplifier may be of any convenient typle and is here shown with resistors R5, R6 and R7 to stabilize and control its operation. The resultant output signal is then taken at the terminals labeled V out~
The strain S is related to the voltage applied to the element 8/8', Vxt by some constant Kl; the voltage produced at the element g/g', Vy~
is related to t.he strain S by some other constant K2 and similarly Vz is related to the strain S by a constant K3 (where Kl, K~ and K3 are functions of the physical construction and also of the piezoelectric properties of the foil).
Hence l x Vy = K2.S
V~ = K3.S
25 and to satisEy the operating conditions of the amplifier Vin. R2 = Vy (Rl~R2 ) and of amplif ier 17 Vout. ~7 - Vz (R -~R ) If Area of active element 9/9' .
Area of active element lO/lO' R3 and Cl is "large", ie.
l ( 3 2.lr.f.R3.R4 where f is the lowest frequency of interest for the ~7~
input electrical signal Vin, then K2 = K3 Hence Vy = Vz and Vin. R2 = Vout. ~7 ~ R ) ~R~7) The transconductance Vout is (R6~R7).R,~ which is independent V1n ~Rl-~R2j.R7 of K1, K2 and K3, ie. the isolator transconductance is independent of the piezoe:lectric properties of the polymer foil~
, :
The application oE an electrical signal between any pair of conducting areas such as the conducting areas 8 and 8l; will cause a strain in the polymer foil due to the piezoelectric properties oE that foil. This strain is present at any part oE the foil between the restraining points 4 and 5;
hence, due to the piezoelectric properties of that foil~ an electrical signal will be produced at each oE
pairs of similar conducting areas 9 and 9' and 10 and 10'.
Fig. 2 shows in a plane v1ew the conducting areas in relation to the surface of the foil.
Referring to Fig. 2; 1 is the piezoelectric polymer foil, 4 and S the restraining points, 11 and 11' are optional holes to as~ist the mechanical and acoustic protection of the active part of the foil, 12 and 12' are the connecting means to the conducting areas 8 and 8', similarly 13 and 13' and 14 and 14' are the connecting means to the conducting areas to 10 and 10l and 9 and 9I respectively.
To ensure that either polarity oE super-imposed strain, resulting from either polarity of electrical signal, can be achieved within ~he foil it must be in a state oE strainu The absence of static pressure would only permit the existance of superimposed tensile strain.
The stakic pressure can be provided by deforming the foil after it has been clamped at the restraining points either by a rigld form 15 as shown in Fig. 3 or by a resilient form; the latter type will result in an acoustic coupling between the active elements in addition to the mechanical coupling be-tween the active elements on the foil and exagerate the need to protect the Eoil Erom external acoustic signals if such protection is necessary for a specific application of the isolator. A rigid form should preferably be as shown in Fig. 3 where 15 is a pro-jection of restraining means 3 so as to stretch the foil 1 to a length 4~15~5 which is longer than the length 4-5. All active element.s are provided on the part of the foil lying between 4 and 15.
The strain in the oil between the restrain-s ing points 4 and 5 is experienced equally by the active elements formed by the areas 9/9' and lO/10';
the electrical signal produced at each of these active elements shoul_ therefore be equalO The source im-pedance of the active elemenl:s 9/9' and 10/lO' depends on the area of these elements and the actual electrical signals ~voltages) are thus dependent on tlle impedance of the electrical circuits connected to those elements;
given that the actual areas are inversely proportional to the actual impedances of the connected circuits then the actual voltages will be equal~
It is not necessary for the areas o any of the active elements to be equal; hence these areas -and their shapes - in a particular implementation can be chosen to optimize the physical separation of the conducting areas so as to achieve the electrical isolation required for a particular application.
Fig. 4 shows an electrical application of the strain coupled mechanical system described in Figs. 1 thru 3. The piezoelectric film is shown as a dashed line betwPen the active elements 8 and 8', 9 and 9' and 10 and 10'. These elements are each shown with the primed element connected to a co~mon ground potential, separate grounds being shown for each side of the isolator. The input or driving elements 8 and 8 t are connected to the output of the input amplifier 16. The input signal is applied at the terminals labeled Vin through a network of resistors Rl and R2 and the input ground to the non~inverting input terminal. The sensed piezoelectric generated signal at the active elements lO and 10' is connected back to the inverting input of the amplifier. The signal from the driving elements 8 and 8' via the network composed of resistors R3 and R4 in the series - ~ -path and capacitor Cl connected to ground from the resistors junction point --- is also connected to the inverting input of the amplifier 16 so as to ensure the correct bias to that ampliier; the capacito~
Cl eEfectively bypasses the variations in output voltage to ground so that the feedback to the amplifier is only of the voltage produced at elements lO/lO'.
The isolated output is taken from the active elements 9 and 9' to an output amplifier 17. This amplifier may be of any convenient typle and is here shown with resistors R5, R6 and R7 to stabilize and control its operation. The resultant output signal is then taken at the terminals labeled V out~
The strain S is related to the voltage applied to the element 8/8', Vxt by some constant Kl; the voltage produced at the element g/g', Vy~
is related to t.he strain S by some other constant K2 and similarly Vz is related to the strain S by a constant K3 (where Kl, K~ and K3 are functions of the physical construction and also of the piezoelectric properties of the foil).
Hence l x Vy = K2.S
V~ = K3.S
25 and to satisEy the operating conditions of the amplifier Vin. R2 = Vy (Rl~R2 ) and of amplif ier 17 Vout. ~7 - Vz (R -~R ) If Area of active element 9/9' .
Area of active element lO/lO' R3 and Cl is "large", ie.
l ( 3 2.lr.f.R3.R4 where f is the lowest frequency of interest for the ~7~
input electrical signal Vin, then K2 = K3 Hence Vy = Vz and Vin. R2 = Vout. ~7 ~ R ) ~R~7) The transconductance Vout is (R6~R7).R,~ which is independent V1n ~Rl-~R2j.R7 of K1, K2 and K3, ie. the isolator transconductance is independent of the piezoe:lectric properties of the polymer foil~
Claims (10)
1. An electrostatic type electrical isolating arrangement comprising: a piezoelectric film as a coupling means;
a first plurality of electrically conductive areas disposed on opposing overlapping surfaces of said film;
a second plurality of electrically conductive areas disposed on opposing overlapping surfaces of said film, remote from said first plurality of elec-trically conductive areas;
and a third plurality of electrically con-ductive areas disposed on opposing overlapping sur-faces of said film, remote from said first and second plurality of electrically conductive areas;
separate electrodes for each of the elec-trically conductive areas;
an input amplifier including an inverting input and a non-inverting input as well as an output;
means connecting said amplifier output to said electrodes of said first plurality of electrically conductive areas;
second means connecting said electrodes of said third plurality of electrically conductive areas to said first amplifier inverting input;
said amplifier operated upon the application of electrical signals to said amplifier non-inverting input to apply signal to said first plurality of elec-trically conductive areas via said corresponding electrodes, said amplifier inverting input connected to said third plurality of electrically conductive areas so that the signals sensed by said third plurality of electrically conductive areas modify said amplifier output and accordingly the corresponding signals generated on said electrodes for said second plurality of conductive areas.
a first plurality of electrically conductive areas disposed on opposing overlapping surfaces of said film;
a second plurality of electrically conductive areas disposed on opposing overlapping surfaces of said film, remote from said first plurality of elec-trically conductive areas;
and a third plurality of electrically con-ductive areas disposed on opposing overlapping sur-faces of said film, remote from said first and second plurality of electrically conductive areas;
separate electrodes for each of the elec-trically conductive areas;
an input amplifier including an inverting input and a non-inverting input as well as an output;
means connecting said amplifier output to said electrodes of said first plurality of electrically conductive areas;
second means connecting said electrodes of said third plurality of electrically conductive areas to said first amplifier inverting input;
said amplifier operated upon the application of electrical signals to said amplifier non-inverting input to apply signal to said first plurality of elec-trically conductive areas via said corresponding electrodes, said amplifier inverting input connected to said third plurality of electrically conductive areas so that the signals sensed by said third plurality of electrically conductive areas modify said amplifier output and accordingly the corresponding signals generated on said electrodes for said second plurality of conductive areas.
2. An electrostatic type electrical isolating arrangement as claimed in claim 1 and further including a resistor network con-nected to said amplifier non-inverting input to achieve a required signal level at said second plurality of electrically conductive areas for a given input signal level.
3. An electrostatic type electrical isolating arrangement as claimed in claim 1 and further including an output amplifier having an input and an output, with said input connected to said second plurality of conductive areas.
4. An electrostatic type electrical isolating arrangement as claimed in claim 2 and further including an output amplifier having an input and an output, with said input connected to said second plurality of conductive areas.
5. An electrostatic type electrical isolating arrangement as claimed in claim 3 and further including a resistor network con-nected to said amplifier to achieve a required output signal level for a given input signal level.
6. An electrostatic type electrical isolator as claimed in claim 1 wherein said piezoelectric film is polyvinylidene flouride.
7. An electrostatic type electrical isolator as claimed in claim 2 wherein said piezoelectric film is polyvinylidene flouride.
8. An electrostatic type electrical isolator as claimed in claim 6 wherein each said plurality of conductive areas is two.
9. An electrostatic type electrical isolator as claimed in claim 6 wherein said piezoelectric film is oriented.
10. An electrostatic type electrical isolator as claimed in claim 6 wherein said conductive areas are of aluminum.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US33324281A | 1981-12-21 | 1981-12-21 | |
| US333,242 | 1981-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189156A true CA1189156A (en) | 1985-06-18 |
Family
ID=23301958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000414821A Expired CA1189156A (en) | 1981-12-21 | 1982-11-04 | Mechanically coupled electrical isolator including output stabilization |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS58111517A (en) |
| BE (1) | BE895400A (en) |
| CA (1) | CA1189156A (en) |
| IT (1) | IT1155024B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4964302A (en) * | 1984-09-25 | 1990-10-23 | Grahn Allen R | Tactile sensor |
-
1982
- 1982-11-04 CA CA000414821A patent/CA1189156A/en not_active Expired
- 1982-12-20 JP JP57222224A patent/JPS58111517A/en active Pending
- 1982-12-20 IT IT24860/82A patent/IT1155024B/en active
- 1982-12-20 BE BE2/59965A patent/BE895400A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| IT8224860A0 (en) | 1982-12-20 |
| JPS58111517A (en) | 1983-07-02 |
| BE895400A (en) | 1983-04-15 |
| IT1155024B (en) | 1987-01-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |