I'm trying to figure out what happens to a 30 Volt supply when it is attached to a circuit of resistors which are not grounded. I know that eventually (steady state) the voltage of the circuit should equal the voltage of the supply, but at that point there would be zero free electrons traveling through the resistor net since there is nowhere for them to travel out of the network. The only place for them to escape would be back into the supply which supplied them in the first place.

Assuming the resistor net was truly at 'zero' with respect to the supply ground at the beginning. My best bet is that the free electrons would charge into the resistor net and upon finding zero escape path, would return through the original supply by artificially increasing their voltage until the supply allowed them to escape to ground (or however it chooses to deal with the situation). At this point the resistor net is now 'at rest' but at a relative steady state potential of 30 Volts.

Let's assume we're using a series of 3 metal oxide resistors with 10k resistance and 50 nH of parasitic inductance. (http://www.resistorguide.com/inductance/ ) What I can't figure out, is what happens to free electrons when they 'hit the end' of the circuit and somehow return upstream back into the supply for their steady state condition to occur.

I understand that inductors have the ability to artificially increase voltage above their supplied current in order to try and preserve their 'current momentum'. Does that increased voltage eventually cause a reverse flow of electrons backwards through the circuit and cause the supply to be the lowest potential point in the circuit to create an outflow of free electrons? Or do the electrons just return backwards through the inductive field despite the field trying to keep them on the 'floating' side of the resistor? I think I'm just not sure what the mechanism would be for reduction of the parasitic inductance of un-grounded resistors and for dealing with the free electrons which charged the inductors in the first place.

If you can help me with the theory, can you also help me with the math behind it? I'd like to understand and be able to model these behaviors. Thank you!

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    \$\begingroup\$ If you assume an ideal open circuit (OC), then there will be no current. If that's too boring, you can admit that the OC is not ideal. For example, you can assume that OC is a capacitor with some small finite value. \$\endgroup\$ – Nick Alexeev Sep 8 '15 at 3:09

Consider that there is a (probably tiny) parasitic capacitance between each node of the "floating" circuit and the ground terminal of the power supply and whatever it is connected to. Now you can analyze this circuit using the usual concepts of conventional current, charge, and voltage. There's no need to worry about electrons.

When the supply is first connected, current flows in to the circuit and returns to the supply's anode through the parasitic capacitors. Once sufficient current has flowed, the capacitors will be charged up to 30 V. No further current will flow and the various nodes of the resistor network will remain at 30 V as you expected.


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