> From:         Dagmar C. Neto[SMTP:dagmarcn@RC.UNESP.BR]
> Sent:         Wednesday, December 17, 2003 12:39 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [EE]: How to generate high voltage symetrical pulses

>         Hi Piclist!
>         I need to generate a low current high voltage (aprox. 80V), low
> current symetrical pulse train, using a 6V or 9V battery. I've made some
> experiences using a "inverted" power transformer and a signal generator,
> but get no pulses out (looking in a osciloscope). The ideia is to use a PIC to
> generate the pulses.
>         I even did buy a low cost "training belt", to passive gymnastics and
> muscle toner, but all that i see when looking at the circuit board is a bunch
> of SMD transistors and resistors, and some caps (I've expected some
> inductors or coils, at last)... and the silicon controller chip sealed by a black
> plastic bubble.
>        Someone can help me? Pointing the error or sugesting some
> schematics...

      You can go wrong in two different directions. First, if the pulses are too short,
      they can be lost in the stray capacitance of the transformer or inductor. This
      is especially a problem if you are using 60 Hz transformers with microsecond
      pulses. Even audio transformers must be used with care. Second, if the pulses
      are too long (wide), and you are using high frequency switching power supply
      transformers, the core of the magnetic device can saturate before the pulse
      ends. This will cause differentiation of the pulse. In other words, only the edges
      of the pulse will appear in the output.
      If you are using a variable frequency and width pulse generator, you should be
      able to find some output from whatever transformer you are using. Once you have
      that, you can go from there to find the limits of that transformer. If you then need
      to go higher in frequency, move on to audio and then switching transformers. If
      you need longer pulses, move in the opposite direction.

      John Power

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu