There is only one current I in a series circuit: I = VT/RT, where VT is the voltage applied across the total series resistance RT. This I is the same in all the series components.
The total resistance RT of a series string is the sum of the individual resistances.
Kirchhoff's voltage law states that the applied voltage VT equals the sum of the IR voltage drops in a series circuit.
The negative side of an IR voltage drop is where electrons flow in, attracted to the positive side at the opposite end.
The sum of the individual values of power used in the individual resistances equals the total power supplied by the source.
Series-aiding voltages are added; series-opposing voltages are subtracted.
An open circuit results in no current in all parts of the series circuit.
For an open in a series circuit, the voltage across the two open terminals is equal to the applied voltage, and the voltage across the remaining components is 0 V.
A short in a series circuit causes the current to increase above its normal value. The voltage drop across the shorted component decreases to 0 V, and the voltage drop across the remaining components increases.
