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Switch Mode Power Supply Plug Packs and dataTaker data loggers

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					www.datataker.com                                                             ~                            ®




          Switch Mode Power Supply Plug Packs and dataTaker
          data loggers.




                                                                                                           Tech Note
          Datataker P/L does not recommend the use of switch mode power supply plug packs. We
          have found that these types of power supplies cause too much noise to be introduced
          into the dataTaker data loggers measurement systems. All dataTaker data loggers are
          generally supplied with an appropriate transformer based plug pack.


          Understanding the problem
          An Audio amplifier and a dataTaker data logger are very similar. Both are designed to
          respond to very small signals. The Amplifiers role is to replicate the original signal without
          distortion. The data logger’s role is to measure and store this signal.

          Just like the audio amplifier the data logger can be affected by unwanted noise.

          One noise source that has been identified is the Common Mode noise generated by
          Universal Switch Mode Power Supply Plug Packs. DataTaker has tested numerous of this
          type of plug pack and found that most have significant common mode noise which gets
          coupled into the precision amplifier section and leads to measurement errors.

          As with good quality audio amplifiers we have decided to supply standard transformer
          based plug packs. These inherently have very low common mode noise.


          Universal Plug Packs (Not recommended)
          A common switched mode power supply plug pack is a “universal” plug pack. These are
          supplied with several power point adaptors for use in many countries that feature different
          voltage and plug arrangements. This type of adaptor will almost certainly be a switch
          mode power supply as this is required to support the large input voltage range to the
          supply. They are generally smaller and obviously more versatile than transformer based
          plug packs, which is the reason for considering the use of these power supplies.




Datataker Pty Ltd
7 Seismic Court Rowville                        Tel: +61 3 9764 8600   Email: support@datataker.com.au
Victoria 3178 Australia                         Fax: +61 3 9764 8997           Web: www.datataker.com
dataTaker is a registered trademark of Datataker Pty Ltd.

TN-0025-A0                                           Page 1 of 1                       14 October 2004

				
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Description: Switch Mode Power Supply Plug Packs and dataTaker data loggers