A logic circuit

[gar]

100303-2227 EST

[FONT="Courier New"]
Looking at an old textbook --- Keister, Ritchie, and Washburn --- 
I saw this simple Network Simplification,  p75 Fig 5-5. This was 
done by a theorem, but is also easy by observation. 

    ---- A ----- B ----- C ----- D -----
    |                                  |
------------ A ------ B ----- E -----------
    |                                  |
    ------------- A ------- F ----------

This simplifies to

            ---- B ----- C ----- D -----
            |        |                 |
------- A ---        ------- E -------------
            |                          |
            ---------------- F ---------

The simplified circuit has 6 contacts vs the original of 9 contacts.
Furthermore, you may more easily understand the logic of the 
simplified circuit.

For better or worse integrated circuits and low cost computers 
changed the way people approached problems.

Before 1970 to 1980 there was much emphasis on logic circuit 
simplification because it was a means of cost reduction and 
reliability improvement.[/FONT]

.

 

[LarryFine]

I get the logic and the conversion from one circuit to the other, presuming these are NM contacts.

What's the question?

 

[gar]

100304-1149 EST

Larry:

No question. Just a random logic problem to provide something not too complex for individuals not familiar with logic circuits to think about.

To help with their general education.

I can add a question for people to chew on. What is a design for a relay circuit to do binary addition?

.

 

[LarryFine]

What is a design for a relay circuit to do binary addition?

Do you mean logic gate type, such as AND and OR gates?

 

[gar]

100304-1354 EST

No.

I was thinking along the line of relay coils and contacts. This requires a more basic approach. I can buy XOR gate devices, and multi input AND and OR gates, and these reduce the design effort compared to relay NO and NC contacts and require less thinking.

The NO and NC contacts are more common to electricians, but a binary adder is not, and thus maybe too much of a challenge.

Obviously one has to create a circuit that responds to three binary inputs --- An, Bn, and Carry n-1, and produce two outputs Out n and Carry n.

Creating a truth table would be a good starting point.

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[dbuckley]

YOu can do some quite impressive logic with relays - have a look here...