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???
05/05/06 18:18
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#115720 - Re: Why Damaged.
Responding to: ???'s previous message
I believe the 74LCX245 is blowing out do to power surges and 11Vac noise/crosstalk. I don't believe the 110Vac lines is actually making physcial connect. The low and high voltage lines are taped next to each other.

Some individuals use MC14050 hex buffer instead of the 74LCX245 and PK682A unidirection transzorb, a .1uF Caps to ground. This circuit is works ok. I am would like to find better circuit than this. I would like to why this seems to work better than
74LCX245 with a bidirectional transzorb. I am assuming it is the transzorbs.

PK682 UNI 77 Standoff
SMAJ5.0 BI 5.0 Standoff


Is it that one Unidirection or standoff voltage that makes the biggest difference.



List of 66 messages in thread
TopicAuthorDate
High Tolerant Input Pins tvs, otpto,            01/01/70 00:00      
   Use a 'srial chip            01/01/70 00:00      
      But..            01/01/70 00:00      
         what's the problem?            01/01/70 00:00      
      Re: Serial Chip            01/01/70 00:00      
         better or not            01/01/70 00:00      
   Suggestion            01/01/70 00:00      
   Input            01/01/70 00:00      
      Why damaged?            01/01/70 00:00      
         Re: Why Damaged.            01/01/70 00:00      
            Another suggestion...            01/01/70 00:00      
               Yes, but...            01/01/70 00:00      
                  Schottky clamps ?            01/01/70 00:00      
                     Diode clamps            01/01/70 00:00      
                        Tranzorb            01/01/70 00:00      
      Try this...            01/01/70 00:00      
   ST overvoltage protection            01/01/70 00:00      
      A bad situation            01/01/70 00:00      
         Russell            01/01/70 00:00      
            My suggestion?            01/01/70 00:00      
   Look for PLC discrete input circuits            01/01/70 00:00      
      partially right            01/01/70 00:00      
         Even a PLC wouldn't like this circuit            01/01/70 00:00      
            OK, It's a switch - question to Scott            01/01/70 00:00      
               Speed of the input            01/01/70 00:00      
                  at lower detection rates ...            01/01/70 00:00      
                     What I recommended...            01/01/70 00:00      
   Steroids Desing            01/01/70 00:00      
      Analyse the circuit            01/01/70 00:00      
         to fully isolate            01/01/70 00:00      
            how about answering            01/01/70 00:00      
               That's obvious isn't it?            01/01/70 00:00      
                  it's not that obvious            01/01/70 00:00      
                     It's just ignorance            01/01/70 00:00      
                        opto couplers            01/01/70 00:00      
                           true enough!            01/01/70 00:00      
                           Not so strange            01/01/70 00:00      
                              Not strange, perhaps, but WRONG!            01/01/70 00:00      
                     It's just ignorance            01/01/70 00:00      
                     maybe you answered this one yourself            01/01/70 00:00      
                        still waiting            01/01/70 00:00      
                           No, though that might help            01/01/70 00:00      
   is this a newfangled idea            01/01/70 00:00      
      Downunder circuitry            01/01/70 00:00      
   Why I use the opto            01/01/70 00:00      
      Perception vs reality            01/01/70 00:00      
      +5V supply, is it isolated?            01/01/70 00:00      
         already asked and asked again            01/01/70 00:00      
            Yes, last try before I leave the thread!            01/01/70 00:00      
               The +5V is Isolated.            01/01/70 00:00      
                  incomplete answer            01/01/70 00:00      
                     Yes, what about the grounds?            01/01/70 00:00      
                        Scott, where are you?            01/01/70 00:00      
                           he left when we asked questions            01/01/70 00:00      
                              Still lost and confused            01/01/70 00:00      
                                 you do not need a scope to answer the qu            01/01/70 00:00      
                                 We cannot help you, if you do not...            01/01/70 00:00      
                                    COM and E-GND            01/01/70 00:00      
                                       still not answered            01/01/70 00:00      
                                          just a minute ...            01/01/70 00:00      
                                             SO let me rephrase: how many ohms betwee            01/01/70 00:00      
                                                Getting Older            01/01/70 00:00      
                                                   if you want help, start with some answer            01/01/70 00:00      
                                                   Problem is much more complex            01/01/70 00:00      
                                                   what do you mean by "dying"            01/01/70 00:00      
                                                      Scott, could you...            01/01/70 00:00      

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