Argiris,

  I can't tell you right off hand what parts to use with a 555
  to get a 1 second timer, but the 555 may not be all that
  accurate.  If it were me, (and it was me not too long
  ago), I would use one of the 8 pin PICS.  I used the 12C672
  because thats what I had at the time.  With this part, you
  can use the internal 4 Mhz oscillator and not have any external
  parts to contend with.  You would have +5, Gnd, and an output.
  Plus you'd have 5 more I/O pins available for more outputs,
  complementary outputs etc.  The cost is about the same for
  each.  I will probably never use a 555 timer again.  The 8 pin
  PICS are much cleaner, and somewhat more accurate when using
  the built in RC oscillator.   And you can have several outputs
  working at the same time.  And each can be different if need
  be.  IMHO the PIC is a better choice.  If you've never worked
  with a PIC before and need help, don't hesitate to ask.

                                           Regards,

                                             Jim




On Tue, 07 December 1999, Lalakis Parafyadas wrote:

>
> Hi there. I'm interested in making a 1Hz frequency generator with a NE555
> timer. What resistors, capacitors do I need and how should I connect them to
> the chip? Thanks in advance, Argiris

jim@jpes.com