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???
12/03/07 04:32
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#147758 - 50 percent duty cycle
Responding to: ???'s previous message
The problem with this 300 hZ solution is that when dividing by 5 the output waveform becomes easily a pulse instead of a 50% duty cycle square wave. That kind of signal is not easy to filter.

Dividing the frequency using harmonics would yield better result but the circuit would also become more complex.

A microcontroller sensing the 50 hZ mains signal and producing a sine wave using PWM is very simple, requires very simple RC oscillator (no chrystal) and IMHO is more versatile plus the fact that the PWM signal does not require multi-pole filter to be conditioned properly.

List of 23 messages in thread
TopicAuthorDate
120V ac 60Hz from 230V ac 50Hz            01/01/70 00:00      
   Go back to the USA...            01/01/70 00:00      
      For a clock?            01/01/70 00:00      
         I know of quartz stabilized inverters            01/01/70 00:00      
            Thanks for the ideas..            01/01/70 00:00      
               I confess, the idea with the camping inverter...            01/01/70 00:00      
                  Kai - I know what you meant            01/01/70 00:00      
                     Kai - I know what you meant            01/01/70 00:00      
   Look at the chip inside            01/01/70 00:00      
      done that many times            01/01/70 00:00      
         That was so kind of you.            01/01/70 00:00      
            Maybe you could take a photo of the innards...            01/01/70 00:00      
               OK will post the photo of the innards...            01/01/70 00:00      
   Are you allowed to open the clock?            01/01/70 00:00      
   Buy an Inverter            01/01/70 00:00      
   Alternative            01/01/70 00:00      
      Another alternative            01/01/70 00:00      
         Phase lock loop            01/01/70 00:00      
            Brilliant!            01/01/70 00:00      
            50 percent duty cycle            01/01/70 00:00      
               Horses for Courses            01/01/70 00:00      
               ???            01/01/70 00:00      
                  Avoid butchering the clock            01/01/70 00:00      

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