US3766404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite d.c. amplifier for use with a touch sensitive electronic switch
Assignee: Magic Dot Inc
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Filing: 1971-11-16
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Granted: 1973-10-16
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Expires: 1991-11-16
Abstract
Abstract A composite D.C. amplifier for use with a touch sensitive electronic switch which has no moving parts and is actuated by the skin resistance of an operator causing a lowering of D.C. resistance across the switch is disclosed. The composite amplifier, in the preferred embodiment, includes five direct coupled transistors and various current limiting and leakage preventing resistors. The amplifier is arranged to accept an input current on the order of nanoamperes from the touch sensitive switch when actuated and provide an output current in the milliampere range or higher to an electrical load and thus appear as an electronic switch which is in a closed or ON condition. The amplifier is also arranged to avoid providing an output current when the switch is not actuated to thus appear as an electronic switch which is in an open or OFF condition.
Inventors
- 👤 W Larson
- 👤 R Warner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:08
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/94; H03K17/96; H03K17/9645
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
545 words
A composite amplifier for providing an output signal in response to a D.C. input signal actuated by the skin resistance of an operator causing a lowering of D.C. resistance across a skin resistance actuated electronic switch, comprising: means for supplying a direct current including first and second terminals, the first and second terminals comprising one common terminal and one terminal of a D.C. voltage differing from the common terminal; first amplifier means including input means and at least two output means, the first amplifier means requiring a D.C. voltage offset of a first polarity be reached before an output signal is provided by the first amplifier means in response to an input signal; current limiting resistive means for connecting the skin resistance actuated electronic switch to the input means of the first amplifier means to provide a D.C. input signal to the first amplifier means upon the lowering of the D.C. resistance path across the skin resistance actuated electronic switch; means for connecting a first output means of the first amplifier means to the first supply terminal; second amplifier means including input means and at least two output means and at least first and second amplifying stages with the first amplifying stage including input means and output means and the second amplifying stage including input means and at least two output means, the second amplifier means requiring a D.C. voltage offset of a second polarity be reached before an output signal is provided by the second amplifier means in response to an input signal, the second polarity being opposite from the first polarity required by the first amplifier means, with the input means of the first amplifying stage comprising the input means to the second amplifier means and the output means of the second amplifying stage comprising the output means for the second amplifier means, and with a junction means within the second amplifier means connecting an output means of the first amplifying stage to the input means of the second amplifying stage; means for connecting a second output means of the first amplifier means to the input means of the second amplifier means; means for connecting the first output means of the second amplifier means to the first supply terminal; leakage resistance means for connecting the junction means of the second amplifier means to the second supply terminal for providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifier, the leakage resistance means having a maximum resistance value of approximately 1/10 of the nonconductive input resistance of the second amplifying stage of the second amplifier means; third amplifying means including input means and at least two output means; means for connecting a second output means of the second amplifier means to the input means of the third amplifier means; means for connecting a first output means of the third amplifier means to one of the first and second supply terminals; and means connected to a second output means of the third amplifier means for providing an output signal from a third amplifier means in response to an input signal to the first amplifier means actuated by the skin resistance of an operator causing a lowering of D.C. resistance across a skin resistance actuated electronic switch.
Claim 2
Dependent Claim
545 words
A composite amplifier for providing an output signal in response to a D.C. input signal actuated by the skin resistance of an operator causing a lowering of D.C. resistance across a skin resistance actuated electronic switch, comprising: means for supplying a direct current including first and second terminals, the first and second terminals comprising one common terminal and one terminal of a D.C. voltage differing from the common terminal; first amplifier means including input means and at least two output means, the first amplifier means requiring a D.C. voltage offset of a first polarity be reached before an output signal is provided by the first amplifier means in response to an input signal; current limiting resistive means for connecting the skin resistance actuated electronic switch to the input means of the first amplifier means to provide a D.C. input signal to the first amplifier means upon the lowering of the D.C. resistance path across the skin resistance actuated electronic switch; means for connecting a first output means of the first amplifier means to the first supply terminal; second amplifier means including input means and at least two output means and at least first and second amplifying stages with the first amplifying stage including input means and output means and the second amplifying stage including input means and at least two output means, the second amplifier means requiring a D.C. voltage offset of a second polarity be reached before an output signal is provided by the second amplifier means in response to an input signal, the second polarity being opposite from the first polarity required by the first amplifier means, with the input means of the first amplifying stage comprising the input means to the second amplifier means and the output means of the second amplifying stage comprising the output means for the second amplifier means, and with a junction means within the second amplifier means connecting an output means of the first amplifying stage to the input means of the second amplifying stage; means for connecting a second output means of the first amplifier means to the input means of the second amplifier means; means for connecting the first output means of the second amplifier means to the first supply terminal; leakage resistance means for connecting the junction means of the second amplifier means to the second supply terminal for providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifier, the leakage resistance means having a maximum resistance value of approximately 1/10 of the nonconductive input resistance of the second amplifying stage of the second amplifier means; third amplifying means including input means and at least two output means; means for connecting a second output means of the second amplifier means to the input means of the third amplifier means; means for connecting a first output means of the third amplifier means to one of the first and second supply terminals; and means connected to a second output means of the third amplifier means for providing an output signal from a third amplifier means in response to an input signal to the first amplifier means actuated by the skin resistance of an operator causing a lowering of D.C. resistance across a skin resistance actuated electronic switch.
Claim 3
Dependent Claim
24 words
The composite amplifier of claim 1, wherein the leakage resistance means comprises A resistor of a value substantially between 1 megohm and 10 megohms.
Claim 4
Dependent Claim
192 words
The composite amplifier of claim 2, wherein: the first amplifier means comprises a first transistor wherein the input means to the first amplifier means comprises the base of the first transistor, the first output means of the first amplifier means comprises the emitter of the first transistor, and the second output means of the first amplifier means comprises the collectOr of the first transistor; and the second amplifier means comprises a Darlington arrangement of transistors wherein the input means of the second amplifier means comprises the base of the first Darlington transistor, the first output means of the second amplifier means comprises the collector of the last Darlington transistor, and the second output means of the second amplifier means comprises the emitter of the last Darlington transistor, and the junction means connects the emitter of the first Darlington transistor with the base of a second Darlington transistor to thereby connect the leakage resistance means from the emitter of the first Darlington transistor to the second supply terminal for providing a shunting path for leakage current from the first Darlington transistor to aid in preventing an increased output current from the composite amplifier.
Claim 5
Dependent Claim
45 words
The composite amplifier of claim 3, including a leakage resistor between the emitter of each transistor in the Darlington arrangement and the second supply terminal for providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifier.
Claim 6
Dependent Claim
81 words
The composite amplifier of claim 4, wherein the first amplifier comprises a PNP transistor; the Darlington arrangement of transistors is formed of NPN transistors; and the third amplifier means comprises an NPN transistor wherein the input to the third amplifier means comprises the base of the NPN transistor, the first output means of the third amplifier means comprises the emitter of the NPN transistor, and the second output means of the third amplifier means comprises the collector of the NPN transistor.
Claim 7
Dependent Claim
61 words
The composite amplifier of claim 5, wherein the means for connecting the collector of the first transistor to the base of the first Darlington transistor includes a leakage resistor connecting the collector of the first transistor to the second supply terminal for providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifier.
Claim 8
Dependent Claim
36 words
The composite amplifier of claim 6, including a resistor from the collector of the first Darlington transistor to the first supply terminal to aid in reducing the effect of any parasitic oscillations in the composite amplifier.
Claim 9
Dependent Claim
27 words
The composite amplifier of claim 7, including a to the first supply terminal to aid in reducing the effect of anY parasitic oscillations in the composite amplifier.
Claim 10
Dependent Claim
76 words
The composite amplifier of claim 1, wherein the first amplifying stage of the second amplifier means includes first and second output means, the junction means connecting the first output means of the first amplifying stage to the input means of the second amplifying stage; and resistance means for connecting the second output means of first amplifying stage to the first supply terminal to aid in reducing the effect of any parasitic oscillations in the composite amplifier.
Claim 11
Dependent Claim
42 words
The composite amplifier of claim 9, wherein the means for connecting the first output means of the second amplifier means to the first supply terminal comprises resistance means to aid in reducing the effect of any parasitic oscillations within the composite amplifier.
Claim 12
Dependent Claim
68 words
The composite amplifier of claim 1, wherein the means for connecting the second output of the first amplifier means to the input means of the second amplifier means includes leakage resistance means for connecting the second output means of the first amplifier means to the second supply terminal foR providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifIer.
Claim 13
Dependent Claim
192 words
The composite amplifier of claim 1, wherein: the first amplifier means comprises a first transistor wherein the input means to the first amplifier means comprises the base of the first transistor, the first output means of the first amplifier means comprises the emitter of the first transistor, and the second output means of the first amplifier means comprises the collector of the first transistor; and the second amplifier means comprises a Darlington arrangement of transistors wherein the input means of the second amplifier means comprises the base of the first Darlington transistor, the first output means of the second amplifier means comprises the collector of the last Darlington transistor, and the second output means of the second amplifier means comprises the emitter of the last Darlington transistor, and the junction means connects the emitter of the first Darlington transistor with the base of a second Darlington transistor to thereby connect the leakage resistance means from the emitter of the first Darlington transistor to the second supply terminal for providing a shunting path for leakage current from the first Darlington transistor to aid in preventing an increased output current from the composite amplifier.
Claim 14
Dependent Claim
45 words
The composite amplifier of claim 11, including a leakage resistor between the emitter of each transistor in the Darlington arrangement and the second supply terminal for providing a shunting path for leakage current to aid in preventing an increased output current from the composite amplifier.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |