Patents by Inventor Andrew D. Mackrell

Andrew D. Mackrell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Detection of electromagnetic radiation
    Patent number: 4889994
    Abstract: A system for detecting ultra-violet radiation has a cold cathode discharge tube which produces a pulse each time it avalanches. A logic arrangement steers these pulses successively to separate timers in that order. In response to each pulse, each timer sends its own output line HIGH for a preset period, the same for all the timers. An AND gate receives all the timer outputs and produces an alarm signal when all these are HIGH at the same time.
    Type: Grant
    Filed: January 7, 1988
    Date of Patent: December 26, 1989
    Assignee: Graviner Limited
    Inventors: Alfred R. Brown, Andrew D. Mackrell