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Why does the current always remain the same in a series circuit?

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Life24

Sep 10, 2015
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Hello,
Why does the current always remain the same in a series circuit?
 
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Old Steve

Jul 23, 2015
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Hello,
Why does the current always remain the same in a series circuit?
It doesn't, unless the load always remains the same.
And you don't need such a big font. Most of us can see OK.

If you mean "Why is the current through all of the components in a series circuit the same?", it's because there is only one current path so it has to be the same.
 

Life24

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Series circuits
A series circuit is a circuit in which resistors are arranged in a chain, so the current has only one path to take. The current is the same through each resistor. The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors:

equivalent resistance of resistors in series : R = R1 + R2 + R3 + ...
 

Life24

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We have voltage drop in each resistor,
for example in resistor one with 20 ohm resistance we have 200V Voltage, so I=V/R ==> 200 / 20 = 10A .
We assume a bit voltage drop in resistor two and voltage is 195 V , So I = V/R ==> 190/20 = 9.5 A
Now we don't have the same current in series circuit :(
 

LvW

Apr 12, 2014
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We have voltage drop in each resistor,
for example in resistor one with 20 ohm resistance we have 200V Voltage, so I=V/R ==> 200 / 20 = 10A .
We assume a bit voltage drop in resistor two and voltage is 195 V , So I = V/R ==> 190/20 = 9.5 A
Now we don't have the same current in series circuit :(

Life24 - are you speaking of two different circuits or of a series connection of two resistors?
 

LvW

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Hello,
Why does the current always remain the same in a series circuit?

For my opinion, it is the other way round:
We speak about a series connection of several parts if - driven by corresponding voltage source - there is the same current through these parts.
 
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Old Steve

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@Life24 , you are very confusing, (or very confused). Please draw a diagram, with resistance values, and supply voltage.
Then we might understand you. So far, you've made no sense at all.
 

Colin Mitchell

Aug 31, 2014
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If you argue about CURRENT IN A NUMBER OF COMPONENTS IN SERIES, then you don't understand the basics of electric circuits. The current is the same in each component.
 

AnalogKid

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We have voltage drop in each resistor,
for example in resistor one with 20 ohm resistance we have 200V Voltage, so I=V/R ==> 200 / 20 = 10A .
We assume a bit voltage drop in resistor two and voltage is 195 V , So I = V/R ==> 190/20 = 9.5 A
Now we don't have the same current in series circuit :(

I'm not picking on you, but your example makes absolutely no sense because in a series circuit there is nothing to "assume." I don't know what a "bit voltage drop" is, but if you meant big voltage drop, that is not something you can just assume when analyzing a series circuit. ever.

ak
 

Life24

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1x99asiijljr.jpg
 

davenn

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@Life24
thanks for your drawings, I has assumed that is what you were referring to :)

in a series circuit as you have shown, the total resistance of the circuit, be it 1 resistor or several resistors, sets the current flow in
the circuit according to Ohms Law I = V/R

that current will be the same where-ever you measure it in the circuit

also, the voltage drops across each resistor, be it 1 resistor or several resistors, will add up to the total voltage of the battery


cheers
Dave
 
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duke37

Jan 9, 2011
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'The current is the same throughout the series circuit because it has nowhere else to go.'

Wkipedia says

Kirchhoff's current law (KCL)[edit]

The current entering any junction is equal to the current leaving that junction. i2 + i3 = i1 + i4
This law is also called Kirchhoff's first law, Kirchhoff's point rule, or Kirchhoff's junction rule (or nodal rule).
The principle of conservation of electric charge implies that:
At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node
The junctions only have one entry and one exit so the current must be the same, it has nowhere else to go. Seems a reasonable explanation?
 

Ratch

Mar 10, 2013
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Hello,
Why does the current always remain the same in a series circuit?

Current is the rate of charge movement. Once the charge moves is in a single conductive path like a series circuit, there is no way that additional charge can be added or taken away. Therefore, all the charge is constrained to move at the same rate, and the current will be the same throughout the series circuit.

Ratch
 

davenn

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OK guys
I have done a major clean up of this thread ...
deleted some odd comments and a number of responses that didn't even answer the OP's basic question
almost want to delete the Kirchhoff's current law response. If Life24 doesn't yet understand something
basic like series circuits, Kirchoff's Law is only going to confuse him/her even more

the Q has been asked and answered OK
as such I will close the thread :)


cheers
Dave
 

chopnhack

Apr 28, 2014
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The OP may want to put these questions in the homework section in the future? It looks like the reason the font was different is because it was copied and pasted over...
 
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