| 摘要 |
<p>A system for detecting UV radiation has a cold cathode discharge tube 10 which produces a pulse on a line 18 each time it avalanches. Logic 20 steers these pulses successively to separate timers 22,24,26,28,30,22,24,.. (and so on) 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 32 receives all the timer outputs and produces an alarm signal when all these are HIGH at the same time.</p> |
