Sunlamp delayed extinction circuit
CA 1046576 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Van Der Meulen, Andries
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a sunlamp device which is provided with a high pressure mercury vapour discharge tube and with an auxiliary device for extinguishing the discharge tube with a given time delay on termination of the desired irradiation period. According to the invention a switch connected in series with the discharge tube is shunted by a resistor having a positive temperature coefficient of resistance (PTC resistor). This ensures that after the switch has been opened on termination of the desired irradiation period the PTC resistor passes current for some time. As a result the resistance of this PTC resistor is increased, which causes the current through the discharge tube to be …
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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 January 16, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 16, 1996.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.