74hct374

[petemoore]

  Dude at RS showed me a box full of 'stuff'
  Many of them are "Flip-Flop's, 3 state trigger...whatever that means .
  I downloaded a data sheet, didn't see any diagrams, having trouble with the terminology or getting near to be able to figure what/why/how to wire it or what they might be useful for.
  74hct'xxx'
  the ____574 says, octal D-Type Flip flop positive edge-trigger 3 state
  the 374 says, octal D type flip flop Pos Dge trigger 3 state
   the 273 says octal D type flip flop with reset: positive edge trigger.
  Any schematics or reads besides those data sheets which I'm mostly having trouble comprehending?
  I buy a pile of chips nobody's using?

[db]

3 state or tri-state as it is more commonly known simply refers to the ability of an output to be either driving low (0), high (1) or high impedance (Z).  This is so you can connect it to a bus with multiple drivers.  These chips are just bog standard CMOS TTL logic chips - they may come in useful for something but they are very general purpose so I wouldn't buy them unless I had a specific need.

[petemoore]

  I got a buncha other stuff too, stuff...norm has a need for...lol.
  I wouldn't buy them unless I had a specific need.
  Difficult to know if I might have a specific need when
  3 state or tri-state means
as it is more commonly known simply refers to the ability of an output to be either driving low (0), high (1) or high impedance (Z).
  And I kinda half follow what...but why and how and where..these could be applied...any options I could look at?
  I don't know what 'octal D' means, perhaps Ill make a...necklace out of e'm.
   This is so you can connect it to a bus with multiple drivers.
  Hmm...one to steer and one to hit the gas and brake?
   These chips are just bog standard CMOS TTL logic chips
  TTL..totally logical. bogged down standards...well maybe I can sell 'em to the next dufus at an even better price.
  Thanks for the post, I'm sure it is well written, but I can't comprehend some of it...I'd like to see an application or description of one..just something so I could know that I probably won't have a call to use them.
  Light show?

[db]

A D type latch is a 1-bit storage device.  You present it with a logic level on the 'D' input (either 0 or 1), and apply a positive going edge to the clock input and the value is stored and presented on the Q output until you repeat the operation or clear that latch using the clear input.  (Some have a set input too).

An octal D is simply a package of 8 of the above with a common clock line and usually a common clear and/or set input.

If you connect the Q output to the D input using an inverter, then you have a flip-flop which changes state each time you apply a clock pulse.  This can be useful for electronic switching i.e. ON-OFF-ON etc.