[Frodo Baggins]

I'm trying to help a girl with Physics, and she asks me this:

Most household plugs are double ones. Are they wired in parallel or in series?

a) They are wired in series, since if they were wired in parallel, you would always have to have two appliances plugged in

b) They are wired in parallel, so they always supply the same current to any appliance.

c) They are wired in parallel, since if they were wired in series, you would always have to have two appliances plugged in

First of all, when they refer to "plug", I HOPE they do not mean the outlet (receptacle, where you plug the 'plugs' in)

Is the answer not a)? Double pronged plugs are in series I believe. So current flows through one prong (the "hot" wire), flows through the appliance, and out through the other prong (neutral)

However, the reason it provides "since if they were wired in parallel, you would always have to have two appliances plugged in" makes no sense whatsoever!


(On the other hand, outlets are different. The two hot wires from the two outlets are hooked up in parallel so that they can get different amounts of charge (and also so if one appliance shuts off, the circuit isn't cut off)...but b) does not apply.)

[bchur83]

B would be the correct answer.

[Frodo Baggins]

Why...?

The two progs in a plug are wired in parallel...?

Besides, it makes no sense because different appliances require different currents, no?

[Romulox]

basic house wiring, does this help

[Frodo Baggins]

Originally Posted by Romulox

basic house wiring, does this help

Not really. Appliances in a house are wired in parallel because otherwise, if you were to shut off one, the entire circuit is cutoff.

But we're talking about the prongs (pins) in a plug.

[deRusett]

This assignment must be a Grade 11 physics course, and the questions written by a Teacher, the Question MUSH be asking about Outlets not Plugs, none of the answers make sense if the question is asking about Plugs.

[K15]

The plug itself is a series circuit, an outlet itself is run on a parallel circuit.

[d]g[ts]

your correct answer is C. Answer b is somewhat a trick since they would supply the same voltage, not current. Current comes from the applied voltage, and the resistance of the load. Answer C does make sence since series wiring requires the circut to be completed by devices pluged into both ends of the receptacle.

Also if receptacles (plugs) were series wired the voltage would drop across each load applied to it leaving neither device with enough voltage to function properly.

[Dell_Axim]

Most household plugs are double ones. Are they wired in parallel or in series?

a) They are wired in series, since if they were wired in parallel, you would always have to have two appliances plugged in

b) They are wired in parallel, so they always supply the same current to any appliance.

c) They are wired in parallel, since if they were wired in series, you would always have to have two appliances plugged in

A is out right away.
B is almost correct, but *voltage* instead of current.
C is correct because the other two choices are wrong. And if they were wired in series, it won't work because neither device will get full voltage (besides two very different loads like a toaster and a night light, although only the night light will work if wired in series).

[Malpine Walis]

Add another vote for option C here.

If they were in series, you would be forced to use every plug in the circuit in order to get any current for anything. Also, if you turned off one thing, everything else would lose power at the same time (just like 1950's era Xmas lights. One bulb goes out and all of them go out. Now you get to try every single bulb until you find the right one). So series makes nor sense whatsoever.

Also B makes no sense because current has nothing to do with series vs. parralel. d]g[ts touched on this with his mention of resistance but you can also look at my sticky in GCRD for all twelve equations for Ohm's law if you want the details.

[rivercom9]

4th vote for C also for the same reasons Malpine Walis, Dell_Axim and d]g[ts stated.

[Aphex_Tom_9]

i loved electronic problems in physics, i was always good at them...im saying c as well.

[crimedog]

it has nothing to do with home wiring or the outlets, just circuits

[Frodo Baggins]

Indeed the answer is C.

But I am confused by many of your explanations.

My interpretation of PLUG is that knobby thingy with 2-3 prongs.
Outlet or receptacle is the thing in the wall that usually has room for 2 plugs.

Now, is this question about the two prongs in PLUGS or about the two female connections in wall OUTLETS?

You see, c) is correct if we're talking about outlets. If the two female connections are in series, then you would need to complete the circuit with two devices attached. (X-Mas tree analogy).

I'm even made more confused by digit's response:

Originally Posted by 'd

g[ts'
Also if receptacles (plugs) were series wired the voltage would drop across each load applied to it leaving neither device with enough voltage to function properly.

Receptacles are NOT plugs!

Originally Posted by Wikipedia

A power socket (electrical socket, power point, mains socket, plug-in, outlet, receptacle, or female power connector) is a connection point that delivers mains electricity when a plug is inserted into it. It is the opposite of a plug, and usually has only female features.

deRusett: The question is from a 1st year, second semester physics quiz for science students.

[K15]

Originally Posted by Frodo Baggins

Indeed the answer is C.

But I am confused by many of your explanations.

My interpretation of PLUG is that knobby thingy with 2-3 prongs.
Outlet or receptacle is the thing in the wall that usually has room for 2 plugs.

Now, is this question about the two prongs in PLUGS or about the two female connections in wall OUTLETS?

You see, c) is correct if we're talking about outlets. If the two female connections are in series, then you would need to complete the circuit with two devices attached. (X-Mas tree analogy).

I'm even made more confused by digit's response:


Receptacles are NOT plugs!



deRusett: The question is from a 1st year, second semester physics quiz for science students.

1st year university? Wow, that's a basic problem in grade 11 physics here (Canada).
I was also confused by the question, outlets/receptactles are most certainly in parallel. Plugs don't make sense for the question.

[Roofles]

Here.

When things are wired in SERIES with one another, they recieve the same CURRENT, but the voltage dropped across each component is different.

When things are wired in PARALLEL with one another, they have the same VOLTAGE dropped across them, but the current through each in different.

House electrical sockets are all in parallel with each other because each appliance needs ~120V but not the same current draw.

This question does refer to the actual outlet. Answer A is wrong because if they were wired in series, both outlets would have to be plugged in for either appliance to be powered on.

Answer B is wrong because if they are wired in parallel they recieve the same voltage, but draw different currents. (See postulate above)

Answer C is correct because since they are wired in parallel not plugging an appliance in creates an open circuit which allows the other appliance to operate. Should they both be plugged in, they are both on.

Hope that helped!

[Feydd]

I'd have to go with C too. I hope i'm right because I got EET 150 (basic electrical circuites) in an hour and we are going to be studying parallel circuits today.

[perfectturmoil]

Just as a side..

C is right, and this is the reason people blow fuses. Everything needs 110 volts. So, from EE stuff, the voltage across paralell branches of a node is equal. The current varies from the load applied. So this is great.. we can plug in whatever we want, and have the same voltage..

BUT.. all of those currents add up. They all must come through the node (which starts at the fuse box). So, you and all your buddies come and start a lan party in your bedroom. Each computer draws 2 amps. All of a sudden, when the 8th friend boots up, all the power goes out. Because your bedroom only has wirings spec'd for 15 amps, so the circuit trips at 15.

And to say a plug is wired in series or paralell makes absolutely no sense. In essence, all a plug is is one resistor. ---/\/\/--- .. You can't wire one resistor in series OR paralell. It just doesn't work that way. You can connect them to a circuit in series or paralell.. but then your talking about the outlets again :- ]

[Roofles]

Each computer draws more than 2 amps. a 500W PSU draws 4.167 Amps, with most 15 Amp breakers you can get ~3 computers on before you trip your breaker.

A simpler way to think of it is this, you have a max of 120V * 15 Amps(or whatever your breaker is) = 1800W of power available to you on any one circuit. So just subtract whatever your powersupply is and ta da!

(A hair dryer draws 10 amps. Go figure)

[ajrettke]

Terribly worded question. Frodo I understand your thoughts completely. I'm a EE and was lost with this because it's so damn vague as to WHAT they're talking about.

For the first 5 minutes of this thread I didn't know if it was outlets as in all the outlets in a room (or whatever is on that breaker), or the actual wiring in the plug (the thing you stick IN the wall...worthless prof), or if this was a trick question.

What type of ignorant, highschool dropout of a professor came up with that? person should be punched in the face and asked to give a letter of resignation (ok maybe that's extreme, but that's bull**** teahing honestly) if thier teaching at the college/university level.

If the wording would have been:
Standard household electrical outlets have 2 recepticles. Are these 2 recepticles wired together in serials or parrallel?
blah blah blah blah.
BOOYASHOCKA, easy to understand and easy to answer if you know difference between P/S wiring.

*EDIT* also roofles, that's kinda not true about a 500W PSU. It draws what it needs to keep it's caps charged and supply the demand of the computer, i.e. you can have one of those 1kw PSU's but most likely your using 300-400watts with a modern high end system OC'ed running full tilt. Then you gotta add a little bit (9% or so for losses of AC to DC...you can checkout the specific PSU and it's loss rating based upon temperature and loads). So you can usualy have much more than 3 pc's on a circuit.