Light bulbs puzzle

[TimeSpaceLightForce]

 

Light up the 27 bulbs on the ceilings of the building

by installing 54 pipes having single wiring inside.

[imatfaal]

Exactly 54 - don't thnk it can be done. Look at any outside corner - it has three pipes coming into it. Call them x, y, and z ; if x links to y then what happens to z?

 

If two wires can share a node as long as there is only ever one wire in a pipe then all the lights can be linked using 28 pipes. Not yet sure if it is possible to make a circuit without wires sharing a node

[fiveworlds]

Call them x, y, and z ; if x links to y then what happens to z?

 

 

You don't need the ground. In England using the ground is mandatory but it isn't in other countries. 27 *2 =54

[TimeSpaceLightForce]

You can light the 27 bulbs by series connection..
that will require 29 pipes w/ single wire, but the output
will not be enough. So the design is a parallel connection.

 

Here is a connection for 5 pipes junction.

[imatfaal]

Serial can be done with 28. Ok for your parallel connection - will think. However

Question 1 - Must we link to circuit or can + / - end at different nodes

[TimeSpaceLightForce]

@imatfaal:

Must we link to circuit or can + / - end at different nodes?

Must spare 2 pipes to connect down from DC source (+) (-) on ground floor.

[Acme]

@imatfaal:

Must we link to circuit or can + / - end at different nodes?

Must spare 2 pipes to connect down from DC source (+) (-) on ground floor.

If all the lights are on ceilings then there is no ground floor in the diagram.

You can light the 27 bulbs by series connection..

that will require 29 pipes w/ single wire, but the output

will not be enough. So the design is a parallel connection.

 

...

In parallel the lights won't be evenly lit. Those on the end of the circuit will be dim and those on the front will be bright. So if by 'output' you mean brightness then both setups will not be 'enough'.

PS In the series 'not enough' scenario, all that is necessary is to up the voltage. Upping the voltage in the parallel circuit will not fix 'not enough'.

[TimeSpaceLightForce]

@Acme

Ground floor terminals are lower than the ceiling by 1 pipe length. (see diagram)

Enough is not necessarily equal bulb output. Serial circuit causes 1/27 wattage output for bulbs.

Additional batteries or transformer are not available. Parallel circuit is better for with a busted bulb

others still lit.

 

To try this, copy image and paste on MS Paint . there you can draw colored lines on the diagram ..

[Acme]

@Acme

Ground floor terminals are lower than the ceiling by 1 pipe length. (see diagram)

Ah...so we have to add two pipes? Then must they be the same length as the other pipes and we can move the input terminals to suit that length?

Enough is not necessarily equal bulb output.

Not sure I understand that. I think I misspoke about the bulbs in parallel dimming farther out on the circuit, but the parallel circuit does draw more current while the resistance in it is lower than in series. In any case, for either circuit all bulbs should burn at the same brightness as long as the bulbs are all the same wattage. I.e. for the same voltage all burn equally dim in series and all burn equally bright in parallel. Oui? So if the power source is a battery then in series you have dim bulbs but long battery life and in parallel bright bulbs and short battery life.

 

Serial circuit causes 1/27 wattage output for bulbs.

Roger that.

Additional batteries or transformer are not available. Parallel circuit is better for with a busted bulb others still lit.

Acknowledge parallel stays lit on bustage. As noted above if a battery is used its life is shortened in parallel as compared to series. If a transformer is used then presumably it has sufficient current for parallel.

 

To try this, copy image and paste on MS Paint . there you can draw colored lines on the diagram ..

Roger that. Hope I didn't draw the discussion too far off topic.

Here's my solution. Checked it 3 times, but you know how that can go.

 

[imatfaal]

Ah...so we have to add two pipes? Then must they be the same length as the other pipes and we can move the input terminals to suit that length?

Not sure I understand that. I think I misspoke about the bulbs in parallel dimming farther out on the circuit, but the parallel circuit does draw more current while the resistance in it is lower than in series. In any case, for either circuit all bulbs should burn at the same brightness as long as the bulbs are all the same wattage. I.e. for the same voltage all burn equally dim in series and all burn equally bright in parallel. Oui? So if the power source is a battery then in series you have dim bulbs but long battery life and in parallel bright bulbs and short battery life.

 

Roger that.

Acknowledge parallel stays lit on bustage. As noted above if a battery is used its life is shortened in parallel as compared to series. If a transformer is used then presumably it has sufficient current for parallel.

 

Roger that. Hope I didn't draw the discussion too far off topic.

Here's my solution. Checked it 3 times, but you know how that can go.

 

 

Very Impressive

 

But 55? There is only one missing space - so you have 53 pipes plus #1 to the positive and #2 to the negative. I think you have two marked #44 but my eyesight is crap

[TimeSpaceLightForce]

@Acme : There must be a pipe to deduct on your layout that will still make it work..Almost done it!

 

@Imatfaal : Without line #44 .. 45,40 & 50 will be cut from circuit.

[Acme]

Very Impressive

 

But 55? There is only one missing space - so you have 53 pipes plus #1 to the positive and #2 to the negative. I think you have two marked #44 but my eyesight is crap

Make that 2 crap eye sights. I do indeed have two #44s. Will fix asa vision clears.

@Acme : There must be a pipe to deduct on your layout that will still make it work. Almost done it!

 

@Imatfaal : Without line #44 .. 45,40 & 50 will be cut from circuit.

Acknowledged one too many pipes. As noted to Imatfaal, I have 2 pipes labeled 44. Both connected to upper-right-rear bulb.

[TimeSpaceLightForce]

Just omit a pipe on your layout and you got it!

[Acme]

Just omit a pipe on your layout and you got it!

Acknowledged. I will also fix the numbering because, well... I just won't be able to live unless it's correct.

This should have it.