How do resistors act in series?

In brief, the overall or net resistance changes and the resistors in series and/or parallel can be represented by a single equivalent resistor.

If you consider series resistors the equivalent resistance of the series would be:

R = R1+R2+ ... +Rx

The equivalent resistance of parallel resistors would be:

1/R = 1/R1 + 1/R2 + ... + 1/Rx

One rule to always remember when dealing with series and parallel resistors is the voltage across each resistor in parallel will be the same as defined in Kirchhoff Voltage Law and the current across each resistor in series will be the same by Kirchhoff Current Law.

More information can be found at this web site.

http://physics.bu.edu/py106/notes/Circuits.html