How to connect VCC on combo logic gates

[Ohms Law]

Hi all:

I am having difficulty connecting the VCC on logic gate IC's.  If I connect 5 to 15 volts to the VCC terminal say for example on a 74LS32N shouldn't this provide VCC for all 4 of the or gates on that chip?  Maybe I am doing something wrong, because this is not what is happening.  Can someone tell me what the purpose is for the VCC terminal on these IC chips because they are not providing any use for me when I hook them up in multisim?

Lew

[kittmaster]

I'm shooting from memory, right click on the gate, select the pins tab, you should see the vcc and gnd pins listed, click in the cell, type the name of the net you want it to attached to i.e. +5V, -5V etc etc.

[Ohms Law]

Now will this make vcc and gnd a input or will they become outputs?  i.e. will they be able to supply the 4 OR gates without me having to connect eire to all 4.  I guess what I am actually trying to find out here what is the actual purpose of this terminal on the IC chip?

Lew

[kittmaster]

If the package has 4 gates, selecting any one of the gates and doing as I mentioned, it affects all the gates globally.  Clearly your new to this, since your question is partly directed as to why, the answer is that in the real world, the gate is packaged as an IC which may have 4 identical gates within one package.  This means the IC will have two power pins for the single IC package > VCC and GND.  So by doing as described, in a circuit board layout, the netlist will be generated so that the software will create a copper trace connection net to those pins to ensure it is powered and verified during a design rule check.  In simulation, the VCC pins value is used to determine what the output will look like, so if the chips VCC is +5V and GND, then the output would swing between +5 and GND.  This value is also used by the measuring devices like the meters, scopes, bode plots etc.   Hope this helps.   Chris

Message Edited by kittmaster on 05-30-2010 07:39 AM