Where do I begin in analyzing this simple linear circuit?

Question

Not asking for someone to analyze it for me, I am just confused by the three voltage suppliers... how do I go about applying KVL? Here is the actual question:

First use KVL to find the voltage across each resistor, then use Ohm's law and KCL to find the current through every element, including the voltage sources.

OK that's fine, but how do I know which way the current flows and how having 3 voltage supplies in parallel effects this? I'm lost, any hints would be most welcome. Here is the circuit:

http://images7.pictiger.com/thumbs/8a/e005134f1833a4f4bbe72f892128ae8a.th.jpg

Answer 1

First, define the loops around which you are going to write the KVL equations. By choosing these loops (or meshes), you also arbitrarily define the direction of current flow in these loops. It helps if all loop currents go in the same direction, either all clockwise, or all counterclockwise.

Write an independent KVL equation for each loop, and thus you have 1 equation for each unknown loop current.

For your circuit, I would start with 3 loops and 3 equations.

In KVL, voltage sources are simply entered directly, instead of as an impedance times current. For instance:
0 = -5 + 100 * (i1 -i2) + 10, where you have 5V and 10 V sources.

The total current through the 100 ohm resistor is (i1-i2), which you determine by solving the set of 3 equations. Positive current flow is in the direction of i1.

Answer 2

KVL:
There is 10 volts in between the 100 Ohm resistors, and 5 volts on each side, so that means there is 10-5=5volts across each 100 Ohm resistor and 5-5=0volts across the 50 Ohm resistor.

KCL & Ohms law:
With 0volts across the 50 Ohm resistor the current is 0. With 5 volts across each 100 Ohm resistor, the current is 50mA flowing in the direction away from the positive lead of the 10V source toward the 5V sources. Since the current in the 50 Ohm resistor is 0, that means that each 50 mA 'leg' flows 'backward' through each 5V source. The total current in the 10V source is twice 50 mA.

To explain it requires solving it.

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Answer 3

each and every resistive linear community could be modelled in 2 techniques: * As a voltage source V equivalent to the open circuit voltage of the community, in sequence with the community's source resistance R * As a present day source A equivalent to the fast circuit present day of the community, in parallel with the community's source resistance R observe what a stunning duality that's. One variety is won from the different via changing the words voltage/present day, open/short, and sequence/parallel. additionally, the voltage source V and present day source A are merely proper via Ohm's regulation V = AR. those 2 fashions are equivalent interior the experience that if somebody merely palms you 2 wires maximum advantageous to the community in a black field, there is not any test or measurement you're able to make externally that would distinguish the two.