Could someone explain the voltage readings on the following "oscilloscopes" of the simulated schematics below:
(I understand the concept of a voltage divider but it seems something less straightforward is happening here)
To be clear, the top source is 12V DC and the lower one is 6V DC. All resistors have the same value.
The first one is simpler:
The second one adds a slight complication:
Sorry for the large size of the photos. I couldn't figure out how to resize them.
Strictly speaking, your circuits are not voltage dividers. The notion of a voltage divider, where the voltage at a point between two resistors is determined by the ratio of their resistances, works only if the resistors are in series. When elements are in series the current that flows through them is exactly the same.
In practice, you can use a voltage divider reliably as long as the current through the two resistors is nearly identical. That means that whatever you connect to the divider must draw much less current than what would flow through the resistors if nothing else was connected. As the difference in current increases the two resistors behave less and less like a "voltage divider".
In your circuits you have made connections that significantly change the current flowing through the resistors, so you can no longer consider these voltage divider circuits. To analyze these circuits on paper you need to use more sophisticated techniques, such as the mesh-current method or the node-voltage method.
