----------------------------------- DtY Mon Sep 15, 2014 4:06 pm Wiring logic gates ----------------------------------- Hey guys, I've just been ordering a bunch of electronics stuff lately. I got a grab bag full of assorted logic gate ICs. But I can't seem to wire them correctly. I've tried three or four (different logic functions, different manufacturers) and either my output comes on, or it doesn't. Changing the inputs doesn't make any difference. I've looked at the wiring diagrams over and over. It seems consistent too, if the output is coming on, all of the outputs will come on. I am powering from a 9V battery on a 5V regulator. My volt metre reports there's 4.98V across positive and negative. If I wire the LED directly to power, it works. I'm pretty sure I have the polarity correct---more on that in a minute. This is how I currently have it wired. The light is coming on with both switches open (it shouldn't, it's an and gate): http://i.imgur.com/IJnfVno.jpg The IC that's in there now is a http://i.imgur.com/QBLC536.jpg I have the little hole-orientation thing facing up. The only thing I can think of, and it's hard to see in the photo, is on the opposite end there's a smaller slightly indented circle, but it seems much more obvious that the one on the top (of that photo) is what is being shown on the wiring diagram. But, I tried flipping it around and it's doing the same thing. I'm hoping there's something completely silly I'm doing wrong here. Thank you! - jeffrey ----------------------------------- DtY Mon Sep 15, 2014 4:58 pm RE:Wiring logic gates ----------------------------------- Figured it out! The inputs aren't just switches, when they're open, they need to be grounded.