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Re: 555 timer...

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Chip,

You just need to invert the output. Lot's of ways to do that. A low cost solution is:

                      R Resistor
|---------> = Low Output. When the transistor is on, this point is low.
High                  /
Output              |/
pin 3 ----->---RRR--| NPN
of 555              |\

You could always just use an inverter chip such as a CMOS CD40106BE or equivalent or even a simple opto-coupler to do the same thing. I have a plethora of chips on hand and usually go that route. But if not, the above would do the trick with a simple 2N2222A or similar.

Take care,
PS: If above ascii-art looks ugly, set email to view in a fixed width font (which I "always" view TCML with).

Tesla list wrote:

Original poster: "Chip Ford" <chipford@xxxxxxxxxxxxxx>

This is kinda off topic but, can someone please help me with this...I am trying to get a 555 timer rectangle pulse (Basic Astable) to stay low longer then it is high...Is this possible? I have achieved near equal (square) but never longer low then it is high?? Thanks for any help.

Chip Ford