Discussion in 'Homework Help' started by markie, Jul 5, 2014.

1. ### markie Thread Starter New Member

Jul 5, 2014
1
0
Hi guys.
I dont know in what pin should be connected to ground
I am confused on Vdd and Vss
Thanks

Last edited: Jul 5, 2014
2. ### MrChips Moderator

Oct 2, 2009
12,657
3,461
CD4078 is an 8-input NOR/OR gate.
I don't know how you would construct a 16 to 4-line encoder with just this gate.

Vss is the source connection, i.e. the source of electrons. Hence the Vss pin would be connected to the negative potential of the battery or the GROUND while Vdd would be connected to the positive potential of the battery or supply voltage, usually between +3 and +18V.

3. ### ericgibbs AAC Fanatic!

Jan 29, 2010
2,606
396
hi,
A CD4078 is an 8 Input OR/NOR Gate.

Vdd is the positive supply and Vss is 0V.

Do you have the datasheet.?

E

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4. ### MrCarlos Active Member

Jan 2, 2010
400
134
Hello markie

Now you only need to build the encoder 16 to 4-line with CD4078 gates.
Surely you've analyzed Their datasheets.
So now you know that these gates have 2 outputs. therefore called NOR/OR.

We will assume that the encoder is 16 to 4 BITs natural binary:
To make the encoder, 4 CD5078 gates are required.
Taking the 4 outputs of the OR gates.
We can name them as Q1, Q2, Q4, Q8.
And the inputs to the encoder:
1, 2, 3,. . . . 13, 14, 15.
The symbol of this encoder would look like the one shown in the attached image.

The formula for Q1 would be:
Q1=1 + 3 + 5 + 7 + 9 + 11 + 13 + 15.
And for Q2 would be:
Q2=2 + 3 + 6 + 7 + 10 + 11 + 14 + 15.
(+ Means OR)

What could be the formula for Q4 and Q8 ??

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• ###### CD4078B 8-Inputs NOR-OR Gate TEXAS INSTRUMENTS.pdf
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Last edited: Jul 8, 2014
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