Circuit design using switches puzzle

[rampantschess]

TL;DR Summary: I am trying to design a circuit using juat a power source, 3 switches (1,2,3) and 3 Resistors (a,b,c) and wires. i want to design the circuit so it satisfies 4 conditions. the first being if all switches are on, the 3 resistors have current flowing in parallel, second, if only switch 3 is on, all 3 resistors are in series, third if switch 2 and switch 3 are on resistor a has current flowing only, and fourth if switch 3 and switch 1 are on then only resistor c has current flowing. I’ve been stump

I am trying to design a circuit using juat a power source, 3 switches (1,2,3) and 3 Resistors (a,b,c) and wires. i want to design the circuit so it satisfies 4 conditions. the first being if all switches are on, the 3 resistors have current flowing in parallel, second, if only switch 3 is on, all 3 resistors are in series, third if switch 2 and switch 3 are on resistor a has current flowing only, and fourth if switch 3 and switch 1 are on then only resistor c has current flowing. I’ve been stumped and dont know what to do. I’ve only been able to satisfy the first two conditions in the same circuit. I summarized the conditions into a truth table but I dont know if it can help me.

 

[berkeman]

Welcome to PF.

Please show us all of your work. We cannot help if you don't show us what you have done. Use the "Attach files" link below the Edit window to upload PDF and JPEG copies of your work. Thank you.

Also, is this for schoolwork?

 

[rampantschess]

Okay here is what I've done, and its a question my prof asked us to think about, like a puzzle.

 

[berkeman]

Okay, thanks. I'll move this to the schoolwork forums, and have a look at your work.

 

[Baluncore]

@rampantschess
Have you considered the possibility that what you are trying to do is impossible?
It may be infinitely quicker to prove that it is impossible, than to solve it.

I would like to see the original problem statement. Do you have a link to where the original problem comes from?

 

[rampantschess]

The original problem statement is just a truth table, I just omitted the combinations where none of the resistors/LED's have current flow.

 

[rampantschess]

And yes I have considered the possibility that the problem might be impossible but he did not give us that as an inherent option which leads me to want to find a solution.

 

[berkeman]

And yes I have considered the possibility that the problem might be impossible but he did not give us that as an inherent option which leads me to want to find a solution.

Looks like proving that it's impossible could earn you extra credit...

 

[Baluncore]

The original problem statement is just a truth table...

There must be some text also. That may contain misleading language. For example: Now that LEDs are involved, we can use diodes as part of the design.

Where did you find the truth table?
Where did the text come from?

 

[berkeman]

Looks like proving that it's impossible could earn you extra credit...

BTW, you might get double-extra-credit if you got creative and solved the problem using SPDT switches instead of assuming SPST switches...

 

[DaveE]

Sorry, I haven't really tried this yet...
But what's the story with switch 3? It's always "on" as you described it.
Something seems wrong with the description.

 

[DaveE]

The original problem statement is just a truth table, I just omitted the combinations where none of the resistors/LED's have current flow.

Show it to us. A good photo with your phone may suffice.

 

[Averagesupernova]

Based on what we've been told and assuming it is an accurate description, I have figured it out. I'll give a clue. Don't worry about which resistor and switch is called A, B, C or 1, 2, 3 until after you have satisfied conditions. Seems counterintuitive, but that's how I solved it in about 5 minutes.

 

[rampantschess]

Based on what we've been told and assuming it is an accurate description, I have figured it out. I'll give a clue. Don't worry about which resistor and switch is called A, B, C or 1, 2, 3 until after you have satisfied conditions. Seems counterintuitive, but that's how I solved it in about 5 minutes.

I'll try this now, thank you!