How to design the following circuit?

[bhavzp16]

How to design the following circuit? Please help...Design a circuit that will light the same number of LEDs as there are active switches. You will utilize three switches as input. The LEDs should be lit as a bar-magnitude display. The output pattern should look as follows: Active Input switch count LED bar-magnitude display (vertical) no switches active 0 - 0 - 0 any 1 switch active 1 - 0 - 0 any 2 switches active 1 - 1 - 0 all 3 switches active 1 - 1 – 1.

[johnsold]

That sounds like an assignment to help you learn how to do it, so I will not give you a complete solution.  The best way to get help is to show what you have tried and to ask specific questions about the parts you do not understand.

What have you been able to do so far? Do you understand the problem? How will you be implementing this? What software or hardware are you using?

Lynn

[bhavzp16]

Hey Lynn,

Thanks for replying, I have tried making the circuit with DIP switch, resistors and LEDs in Multisim.

It worked fine but the Lab sheet says Logic circuit so i wasnt sure that I have to use logic gates or not.

I wanted to ask this to my Prof but someone passed away in her family and she left early and after I did not bother her.

I would really appreciate your kind help if you do help me with the circuit.

Thanks,

Bhavin

[johnsold]

Bhavin,

That does sound like she wants you to use logic circuits.

When designing a logic circuit, I find it useful to create a truth table. Start with three columns representing the states of the switches. Be sure you have a row for each possible combination of the switches - 8 rows for 3 switches. Next add three columns for the LEDs.  For each row (or set of swithch positions) determine which LEDs need to be ON and mark the columns appropriately.

Then see if you can design a logic circuit which will drive each of the LEDs.

If you continue to have problems, post your truth table and your attempts to design the circuits.

Lynn