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???
03/28/08 01:15
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 		 #152641 - Sorry, but I see a contradiction...
Responding to: ???'s previous message
You earlier wrote:

Asok said:
Relay solenoid is driven by Mains near neutral since here there is no sensitive triac.In this case if mains polarities,LIVE and NEUTRAL,are not reversed even touching CPU Vcc will not give shock.These equipments has to be installed by the manufacturers.


This doubtlessly means, that reversing neutral and phase WILL or CAN give a shock. Or am I wrong?

If I'm right, than even telling the manufacturer how to connect the thingy to mains will not give you any safety guarantee.

By the way, why, at all, omitting the mains transformer? There are ultra small mains transformers available today, offering nearly ideal isolation.
With your relay solution, you would need to choose a safety relay, providing safety gaps between the terminals. These relays must also have been tested against high voltages.

Kai

List of 44 messages in thread
TopicAuthorDate
Possibly noisy Relay/Switch Inputs            01/01/70 00:00      
   Schmitt inverter            01/01/70 00:00      
      Thanks Steve but please note change            01/01/70 00:00      
         Steve's suggestion is certainly valid!            01/01/70 00:00      
            Thanks Richard            01/01/70 00:00      
               Do you really need the optoisolators?            01/01/70 00:00      
         Why Schmitt Gates            01/01/70 00:00      
            That is the purpose of Schmidt-triggers ...            01/01/70 00:00      
   This is how I would do it            01/01/70 00:00      
      I'd probably do that too, except ...            01/01/70 00:00      
      Thanks            01/01/70 00:00      
         The waters have been muddied ...            01/01/70 00:00      
            Thanks            01/01/70 00:00      
               Yes, it's clearer, but ...            01/01/70 00:00      
                  Priority Encoder Not a Good Idea            01/01/70 00:00      
                     Yes, highest priority input would mask others            01/01/70 00:00      
                     Welcome Sir Michael Karas            01/01/70 00:00      
                        Note Length & Cadence on One Timer            01/01/70 00:00      
         Noise            01/01/70 00:00      
            It's all analog            01/01/70 00:00      
   Another way to do this            01/01/70 00:00      
   how fast do you need to detect the contacts            01/01/70 00:00      
      Hello Erik,Hello Kai,            01/01/70 00:00      
         what are you describing?            01/01/70 00:00      
            actual distance test(ohmically)            01/01/70 00:00      
               please answer questions            01/01/70 00:00      
                  Part success            01/01/70 00:00      
                     In the last analysis, it is up to you            01/01/70 00:00      
                        Provocative            01/01/70 00:00      
                           totally irrelevant            01/01/70 00:00      
                     what 'common'            01/01/70 00:00      
                     Transformerless supply...            01/01/70 00:00      
                        Thanks            01/01/70 00:00      
                           I do not understand, parallelling switches            01/01/70 00:00      
                              Absolutely deadly dangerous!!!!            01/01/70 00:00      
                              parallelling switches            01/01/70 00:00      
                                 Sorry, but I see a contradiction...            01/01/70 00:00      
                                    shock? touching what?            01/01/70 00:00      
                                       Come on!            01/01/70 00:00      
                                          The standard to which we designed ...            01/01/70 00:00      
         I believe you may have missed the point            01/01/70 00:00      
   Current rating of relay?            01/01/70 00:00      
      not to nitpick, but            01/01/70 00:00      
         Thank you very much Erik            01/01/70 00:00      

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