555 Timer

[Mark]

Well I was just about to finish putting together my 555 times opto isolator and scr part of the SSG, page 47 in the book. Got all the parts out and low and behold my 555 timer has no schamtic on it! 4 legs on 2 sides but dont know which was is 1, 2, 3, etc. DANG IT! Is there a specific kind of 555 timer or are they generally all the same. I have a JIM-PAK of 6 timers, LM555CN-Linear Series. I paid $5.00 for all 6. Are these the right kind? And other than a little dot over 1 of the terminals there are no other numbers indicating which posts are which. Can anybody help.

[Jetijs]

This might help you:



Put the 555 chip on the desk so that it stands on its legs. Now align it so that the dot is pointing up. The upper left pin will be pin1, the second (from top) left pin will be pin2 and so on till the pin4. The pin5 is the one on bottom right and now the count goes upwards. The upper right is then pin8.
Hope this helps

[Mark]

Thanks Jetijs!!

[Bob Smith]

Links to 555 Tutorials/Info

Mark,
Here are also some links to tutorials that might help you better understand the 555:

555 Timer Calculator

http://www.doctronics.co.uk/555.htm

555 Timer/Oscillator Tutorial (my favourite -van Roon has a number of helpful tutorials online).

Have fun!
B

[Radiant-1]

555 and other circuit simulator

@ Mark and all

This an excellent application that has many good circuits...and you can design your own...It's an applet so you'll need Java
Circuit Simulator Applet
For 555s got to the top menu click "circuits" then "555 timer chip" then "square wave generator"

[Jetijs]

Thank you Radiant-1,
great link. Already bookmarked it

[Radiant-1]

Your welcome

Glad you liked it Jetjis...I used it alot when picking 555 operating frequency ranges.