There is only one path for current flow in a series circuit.
Referring to the circuit above, note that the physical components are
identified as R1 R2, R3, E1 and E2. The electrical values are
associated with the physical components by the use of subscripts.
Voltage drops across the resistors are identified as ER1, ER2 and ER3.
The current flowing through each resistor is identified as I R1 I 2 and
IR3. Each value, such as ER1 or IR2, is specifically associated with a
component by the proper use of subscripts (R1 and R2). The total
current flow in the circuit is measured by the indicated meter and
identified as It.
What is the definition of a series circuit?