Series Circuit example

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G

G._S._Ohm

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DC area
If a source is connected to a load with a hot and neutral wire, this circuit has two nodes.

If you decide the 0.2 ohm resistance in each wire is significant to the circuit operation then you have four nodes.

If you take into account contact resistance at each connection you have even more nodes.
 
E

Eddy Current

Senior Member
Dennis Alwon said:
Normally outlets are done in parallel but a series connect would be just like the old xmas lights used to be- if one goes out the connection is lost. Here is an example of lighting in series.

seriescircuit.gif



Here are receptacles in parallel

multiple recet cr.jpg
Click to expand...

Shouldn't the black be spliced and pig tailed like the ground at the bottom for it to be parallel in the second picture?
 
Dennis Alwon

Dennis Alwon

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I am sorry but I am having a hard time with the use of the term series. It makes me think of a series connection and it is not a series connection. I can't get past that.
 
J

jeffrey3001

Member
xmas lights

xmas lights

So If xmas lights are wired in series, why doesn't the last bulb appear not as bright as the first one. I looked this up online but couldn't find it. Also, I was having a conversation with someone last night who hangs xmas lights, and he was telling me they have a shunt gone to find out which bulbs are bad but he couldn't tell me how it worked. Anyone heard of this?
 
Dennis Alwon

Dennis Alwon

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Eddy Current said:
Is the black wire not going from one receptacle to the next just like a series circuit?
Click to expand...
Sure but the circuit is not a series. In a series the wiring is not directly attached/connected to the first wire but rather it is connected thru the light bulb or the equipment plugged in. I realize this is semantics but I find it awkward to even use the word series here.
 
E

Eddy Current

Senior Member
jeffrey3001 said:
So If xmas lights are wired in series, why doesn't the last bulb appear not as bright as the first one. I looked this up online but couldn't find it. Also, I was having a conversation with someone last night who hangs xmas lights, and he was telling me they have a shunt gone to find out which bulbs are bad but he couldn't tell me how it worked. Anyone heard of this?
Click to expand...

Oh i see so the equipment makes it a parallel circuit.
 
mivey

mivey

Senior Member
Dennis Alwon said:
I am sorry but I am having a hard time with the use of the term series. It makes me think of a series connection and it is not a series connection. I can't get past that.
Click to expand...

Dennis Alwon said:
Sure but the circuit is not a series. In a series the wiring is not directly attached/connected to the first wire but rather it is connected thru the light bulb or the equipment plugged in. I realize this is semantics but I find it awkward to even use the word series here.
Click to expand...

As I said, it is terminology. You are not thinking of the conductors being in series because you are neglecting the series impedance. See if this makes it clear as mud:

Series_Parallel_zpsdc920cc6.jpg
 
kwired

kwired

Electron manager
Location
NE Nebraska
The circuit has both series and parallel components within it. It is not strictly a series or parallel circuit.

The loads on typical general utilization circuits are parallel to one another. The overcurrent device is in series with the rest of the circuit, any simple on/off control devices are in series with the controlled portion of the circuit, but for more complex control there can be paralleled control devices.

A receptacle is a device that (usually) has more than one conductor of the circuit attached to it, and its purpose is to make taps to whatever is inserted into it. When talking basic theory, a multipole receptacle is just multiple junction points on one assembly, with easily separable parts that are the plug assembly. Otherwise the receptacle for the most part is just a certain point in the conductors, it is not a load.
 
G

G._S._Ohm

Senior Member
Location
DC area
jeffrey3001 said:
So If xmas lights are wired in series, why doesn't the last bulb appear not as bright as the first one. I looked this up online but couldn't find it. Also, I was having a conversation with someone last night who hangs xmas lights, and he was telling me they have a shunt gone to find out which bulbs are bad but he couldn't tell me how it worked. Anyone heard of this?
Click to expand...
The current in all parts of a series circuit is the same so all bulbs should be equally bright.

Series'ed bulbs have a shunt that 'fires' when the filament opens and provides current so the rest of the bulbs stay lit. It's several turns of fine wire but I can imagine what material this wire is made of. At 2.4v it presents a high resistance (probably more than 100 ohms) but at 120v it presents a low impedance, see below.

Measurements I made while trying to repair a 100 bulb light string (two strings in parallel but you wouldn't know it by looking, so each bulb must be 120v/50 = 2.4v) showed that the cold filaments measured 1.5 Ω, the shunt measured about 0.5 Ω when fired and the hot resistance by calculation is about 9x that of the cold resistance.
Bulbs with shunts fired will shorten the life of the rest of the string.

If you try light repair, make clips from clothespins, paper clips and stranded wire so you establish reliable connections to the bulbs and sockets. And keep track of where on the string you have established that you do have continuity.

I wouldn't do this normally for as cheap as light strings are but this is getting to be a personal vendetta for me.
 
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