Zero crossing detection circuit
CA 2069168 A1 · Owner: Hoekman, Earl B. · Inventors: Hoekman, Earl B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A zero crossing detection circuit produces an output signal which changes state to indicate the occurrence of a positive-going zero crossing of an AC input signal. The circuit includes first and second input terminals a current sensitive switch such as an opto-isolator first and second, current regulators, and a voltage limiter. The first current regulator is connected in series with the current sensitive switch, and the voltage limiter is connected in parallel with the first current regulator and the current sensitive switch. The second current regulator is connected between the first input terminal and the parallel combination of the voltage limiter and the first current regulator and the …
Read the whole patent
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
- Filed May 21, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 21, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 21, 2014.
- 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.