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???
08/08/06 14:00
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 		 #121856 - Please do as I have asked: connect the buzzer
Responding to: ???'s previous message
resistor down to merely 27ohm .... I think the reason behind this is that P1.0 could not source enough current to drive the transistor
I do not know which defrivative you use (have you stated it?) but 27 ohms equals ~200mA and I know no derivative that can supply more than 20mA 'safely'

Something is very strange: I know of no transistor with a gain of less than 10 and with a gain of 10 200mA base current equals 2A buzzer current.

Please do as I have asked: connect the buzzer to batteries through an ammeter and post how much current the buzzer sucks. Once that is known, a working design will be easy to come up with. Also, connect a scope across the ammeter to see the 'pulse current' (who knows what the characteristics of the buzzer is)

Erik


List of 40 messages in thread
TopicAuthorDate
Does logic "low" represent 0V?            01/01/70 00:00      
   The diagram does not work            01/01/70 00:00      
      What current are we talking about?            01/01/70 00:00      
      More details needed!            01/01/70 00:00      
   Using a transistor            01/01/70 00:00      
      Yes, but...            01/01/70 00:00      
         bear in mind            01/01/70 00:00      
            Of course, but...            01/01/70 00:00      
         forgot to mention: cookbook was for a piezo buzzer            01/01/70 00:00      
            In such a case...            01/01/70 00:00      
      Low hissing sound            01/01/70 00:00      
         Try            01/01/70 00:00      
            Circuit details and summary of my problem            01/01/70 00:00      
               either a mistype or connecting the buzzer the wron            01/01/70 00:00      
                  Update            01/01/70 00:00      
                     Please do as I have asked: connect the buzzer            01/01/70 00:00      
               What you tell is confusing...            01/01/70 00:00      
                  As mentioned by Kai Klaas            01/01/70 00:00      
                     Do not 'believe' MEASURE and be sure            01/01/70 00:00      
               Solving buzzer problem            01/01/70 00:00      
   Barbecue?            01/01/70 00:00      
   Type of buzzer            01/01/70 00:00      
      who knows how much power, how big spikes            01/01/70 00:00      
      Again...            01/01/70 00:00      
         Yeah            01/01/70 00:00      
            Try this!            01/01/70 00:00      
               just guessing            01/01/70 00:00      
                  guessing the current is below 5A...            01/01/70 00:00      
                     then what if it is 1uA            01/01/70 00:00      
                        Sorry.            01/01/70 00:00      
                     We just do not want to guess!!            01/01/70 00:00      
                        Sorry.            01/01/70 00:00      
                           No need to appologize, dear Leonardo...            01/01/70 00:00      
                           not a metter of apology            01/01/70 00:00      
               Buzzer Problem Solved            01/01/70 00:00      
                  Nice to know            01/01/70 00:00      
   No longer interested, Eugene??            01/01/70 00:00      
      of course not            01/01/70 00:00      

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