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Expired Canadian patentCanada

Electronic thermostat

CA 1114474 A · Owner: Levine, Michael R. · Inventors: Levine, Michael R.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A thermostat for generating control signals for a furnace, air conditioner, or the like, employs a constant frequency periodic source and an oscillator incorporating element having a thermal-sensitive electrical characteristic so the oscillator frequency varies as a function of the ambient temperature. A comparator receives the two outputs and generates a signal representative of the ambient temperature. The stable output is also provided to dividing circuits to generate a signal representative of the time that is used to interrogate a digital memory storing a desired temperature-time program for the thermostat for a repetitive period such as a week or month. The ambient temperature signal …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted December 15, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 15, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 11, 1979
GrantedDecember 15, 1981
Term endedDecember 15, 1998
Patent numberCA 1114474 A
Classification (IPC)G01K7/00

Timeline

Timeline From CIPO dates

1980198219841986198819901992199419961998Application filedDec 11, 1979Patent grantedDec 15, 1981Term endedDec 15, 1998

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.