US3861589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature control system and thermostat therefor
Assignee: TDK Micronas GmbH
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Filing: 1974-03-12
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Granted: 1975-01-21
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Expires: 1994-03-12
Abstract
Abstract A two wire thermostat utilizing at least four resistors and a differential amplifier. The amplifier output is connected to one lead of the two wire line. One of the resistors is variable. Another is a thermistor. A first auxiliary resistor which may be employed in one power lead of the amplifier performs two functions. It provides positive feedback for a more stable regenerative snap on and off. It also makes the amplifier gain more nearly constant over an applied voltage swing of from about 0 to 12 or 0 to 24 volts. The applied voltage may be obtained from any source of D.C. or A.C. potential. If the source is A.C., the voltage may be a half wave or full wave rectified sine wave. A second auxiliary resistor may be employed in the other power lead of the amplifier to provide additional positive feedback to the inverting input of the amplifier. This provides a cleaner opening of the circuit when the voltage across the thermostat is low. A diode in one lead of the two wire line can perform three functions. It can provide rectification. It can also provide reverse voltage protection. Further, it can provide heat anticipation. A capacitor connected between the amplifier inputs provides some memory during off periods of a half wave A.C. cycle.
Inventors
- 👤 Elmer A Carlson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:42
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906; G05D23/1909
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
329 words
A temperature control system comprising: a thermostat located in a space, the temperature of which is to be controlled, said thermostat having first and second leads; a power supply having first and second leads; and a device actuable to change the heat content of said space, said device having first and second leads, the second lead of said device being connected to the second lead of said power supply, the first lead of said power supply being connected to the first lead of said thermostat, the first lead of said device being connected to the second lead of said thermostat, said thermostat including a first resistor, a second resistor, a third resistor, a fourth resistor, a first junction, a second junction, a third junction, a fourth junction, a fifth junction, and a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said thermostat first lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth junction, said third resistor being variable, said fourth resistor being temperature sensitive, said fourth junction being connected to said fifth junction, said fifth junction being connected to said thermostat second lead, said thermostat also including a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said thermostat first lead.
Claim 2
Dependent Claim
329 words
A temperature control system comprising: a thermostat located in a space, the temperature of which is to be controlled, said thermostat having first and second leads; a power supply having first and second leads; and a device actuable to change the heat content of said space, said device having first and second leads, the second lead of said device being connected to the second lead of said power supply, the first lead of said power supply being connected to the first lead of said thermostat, the first lead of said device being connected to the second lead of said thermostat, said thermostat including a first resistor, a second resistor, a third resistor, a fourth resistor, a first junction, a second junction, a third junction, a fourth junction, a fifth junction, and a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said thermostat first lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth junction, said third resistor being variable, said fourth resistor being temperature sensitive, said fourth junction being connected to said fifth junction, said fifth junction being connected to said thermostat second lead, said thermostat also including a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said thermostat first lead.
Claim 3
Dependent Claim
268 words
The invention as defined in claim 1, wherein said thermostat includes a fifth resistor, a sixth resistor, and first and second capacitors, said fifth resistor being connected from said third junction to said sixth junction, said sixth resistor being connected from said fourth junction to said fifth junction, said first capacitor being connected from said first junction to said second junction, said second capacitor being connected between said first and second thermostat leads, said power supply including a battery having a positive pole connected to said thermostat first lead, and a negative pole connected to the said second lead of said device, said device including a gas furnace having a valve including an operator winding, said winding having first and second leads connected to the first and second leads of said device, respectively, the first signal input lead of said differential amplifier being the inverting input lead thereof, the second signal input lead of said differential amplifier being the noninverting input lead therEof, said thermostat further including a diode connected from said fifth junction to the second lead of said thermostat and poled to be conductive in a direction toward said thermostat second lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode, said fourth resistor being a thermistor, said third resistor being connected from said sixth junction to said first junction, said fourth resistor being connected from said fourth junction to said first junction, a light emitting diode connected between said amplifier output lead and said first thermostat lead.
Claim 4
Dependent Claim
321 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said third junction to said sixth junction; a sixth resistor connected from said fourth junction to said fifth junction; a diode connected from one of said fifth and sixth junctions to one of said first and second main leads, respectively, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 5
Dependent Claim
321 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said third junction to said sixth junction; a sixth resistor connected from said fourth junction to said fifth junction; a diode connected from one of said fifth and sixth junctions to one of said first and second main leads, respectively, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 6
Dependent Claim
81 words
The invention as defined in claim 3, wherein the first signal input lead of said differential amplifier is the inverting input lead thereof, the second signal input lead of said differential amplifier being the noninverting input lead thereof, a capacitor connected from said first junction to said second junction, said fourth resistor including a thermistor, said third resistor being connected from said sixth junction to said first junction, said fourth resistor being connected from said fourth junction to said first junction.
Claim 7
Dependent Claim
313 words
A thermostat comprising: a first main lead, a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction; said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable reSistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said third junction to said sixth junction; a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 8
Dependent Claim
313 words
A thermostat comprising: a first main lead, a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction; said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable reSistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said third junction to said sixth junction; a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 9
Dependent Claim
81 words
The invention as defined in claim 5, wherein the first signal input lead of said differential amplifier is the inverting input lead thereof, the second signal input lead of said differential amplifier being the noninverting input lead thereof, a capacitor connected from said first junction to said second junction, said fourth resistor including a thermistor, said third resistor being connected from said sixth junction to said first junction, said fourth resistor being connected from said fourth junction to said first junction.
Claim 10
Dependent Claim
313 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said fourth junction to said fifth junction; a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 11
Dependent Claim
313 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; a fifth resistor connected from said fourth junction to said fifth junction; a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 12
Dependent Claim
81 words
The invention as defined in claim 7, wherein the first signal input lead of said differential amplifier is the inverting input lead thereof, the second signal input lead of said differential amplifier being the noninverting input lead thereof, a capacitor connected from said first junction to said second junction, said fourth resistor including a thermistor, Said third resistor being connected from said sixth junction to said first junction, said fourth resistor being connected from said fourth junction to said first junction.
Claim 13
Dependent Claim
302 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; and a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 14
Dependent Claim
302 words
A thermostat comprising: a first main lead; a second main lead; a first resistor; a second resistor; a third resistor; a fourth resistor; a first junction; a second junction; a third junction; a fourth junction; a fifth junction; a sixth junction, said third resistor being connected from one of said fourth and sixth junctions to said first junction, said fourth resistor being connected from the other of said fourth and sixth junctions to said first junction, said third and sixth junctions being connected together, said first main lead being connected to said sixth junction, said first resistor being connected from said third junction to said second junction, said second resistor being connected from said second junction to said fifth resistor, said third resistor having an adjustable resistance, said fourth resistor having a resistance which changes with a predetermined variable, said fourth junction being connected to said fifth junction, said fifth junction being connected to said second main lead; a differential amplifier having a first signal input lead, a second signal input lead, a first power input lead, a second power input lead, and an output lead, said first power input lead being connected to said third junction, said second power input lead being connected to said fourth junction, said first signal input lead being connected from said first junction, said second signal input lead being connected from said second junction, said output lead being connected to said first main input lead; said fourth resistor being a temperature sensitive resistor; and a diode connected from said fifth junction to said second main lead and poled to be conductive in a direction toward said second main lead, said diode being fixed relative to and contiguous to said fourth resistor in heat exchange relationship therewith to heat the same when current passes through said diode.
Claim 15
Dependent Claim
81 words
The invention as defined in claim 9, wherein the first signal input lead of said differential amplifier is the inverting input lead thereof, the second signal input lead of said differential amplifier being the noninverting input lead thereof, a capacitor connected from said first junction to said second junction, said fourth resistor including a thermistor, said third resistor being connected from said sixth junction to said first junction, said fourth resistor being connected from said fourth junction to said first junction.
References Cited (Backward Citations)
US3535561A
Cited
US3623545A
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