Im new to the forum so quick Hi

Ok basically i'm building a basic alarm set up as part of a project work i have everything sorted apart from a simple astable 555 timer to run a flashing led and a siren. for some reason Tina Pro the software i use keeps bringing up errors. ill add a screen shot if somebody could shed a little light on this i would be most appreciative.

Thanks in advance
Anthony

http://yfrog.com/mufaildip <<<<<screenshot

 

You have DISCHARGE tied close to Vcc, try disconnecting it, or a bypass cap to ground and see what happens.

 

great thanks i stuck a 0.01u cap in and work great

looks like a jumped the gun there a little its not actualy creating a pulse if i grond the discharge here is the schmatic im following http://www.instructables.com/id/A-fairly-simple-555-tester/step2/Putting-it-all-together/

 

When you use those test points (VF1), you must have a ground somewhere.

How fast did you want those led's to flash? You have them flashing very quickly right now.

 

just fast enough to creatt a flashing led this was another shot at it
http://img809.imageshack.us/img809/715/faill.png

 

since you keep guessing, I'm going to recommend you read the 555 portion of the ebook here ... http://www.allaboutcircuits.com/vol_6/chpt_8/1.html

Are you pressing the DC button on the top of your simulation program?

 

im using transiants as 555 dosnt have a DC floating point and im not guessing im following diagrams from the net iv found but no luck.

 

Do you know what parameters you set for the transients? Also set the transients to

In the interactive transient mode, check the timing you want, and then select zero initial values. The default is calculate operating point. If you want that VF1 test point to display properly, place a ground on the negative terminal of the battery.

I still stand by my earlier recommendation about you reading the ebook section.

Here are the results from your latest guess. You will notice the duty cycle is large ... the off time (zero volts) is very, very short.