US3833859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature control system and thermostat therefor
Assignee: TDK Micronas GmbH
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Filing: 1973-03-23
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Granted: 1974-09-03
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Expires: 1993-03-23
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 zero to 12 or zero 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
- 👤 E Carlson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:14
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906; G05D23/1909
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
275 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 junction, 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; and 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, and a sixth resistor connected from said fourth junction to said fifth junction.
Claim 2
Dependent Claim
275 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 junction, 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; and 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, and a sixth resistor connected from said fourth junction to said fifth junction.
Claim 3
Dependent Claim
75 words
The invention as defined in claim 1, 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 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 4
Dependent Claim
329 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 junction, 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; and 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, 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 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 5
Dependent Claim
329 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 junction, 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; and 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, 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 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)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |