<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt"><div>
</div><div style="margin-bottom: 0cm;"> Following inquest for water level
detector. The Atmospheric Environment Service are using
</div><div>
</div><div style="margin-bottom: 0cm;">trysistor, (rectifier with a gate )
ever since the silicon devise was commercialize, for there rain gauge
instrument. With absolutely no problem, with accuracy better than 1/2
a mm. Two little aluminium feelers adjustable with a mechanical
screws to adjust and lock into position. No problem with the natural
rain fall ( presumably rain fall is not absolutely pure,) or the
container (rain gauge) provide enough conductivity, this was not ever
a problem when a was working there. Now the rain gauge is replaced by
a more accurate standard (word wide) a 10 X 10 cm. flat plate, with a
pressure sensor. to record rate of water fall, integration provide
the total rain fall. But here and there rain bucket still exist for
voluntary weather amateurs or scientist. In my time at the AES. the
firing of the trysistor activated a small relay with normally close
contact the relay was passing the trysistor currant when normally
closed, the opening of the contact would cut off the trysistor
current and provide a pulse, recorded on paper or other devices. Most
of instrumentation for the weather service function not attended and
minimum batteries current is necessary.</div><div>
</div><div style="margin-bottom: 0cm;">P.S. A trysistor turn off or on in
microsecond when the circuit has no reactive component, a fast small
relay takes milisecond. With rective component the trysistor is
subject to high inpulse voltage and must be protected from those. Michel Moschos</div><div>
<br></div></div></body></html>