Georg Simon Ohm was a German physicist who gave his name to the electrical quantity resistance. Written with the character Ω (Omega), represented by R in formulas. Popularly, "resistance" is often used to describe resistance, even about the component resistor. It is widely used to describe all electronic devices and even sometimes in batteries that, among other things, restrict current. See also NTC and PTC.
A parallel connection is used in batteries to connect multiple cells. The total voltage does not increase however with current capacity, as well as total battery capacity in ampere hours and watt-hours. See also serial connection.
PTC resistors are temperature-dependent components which in special designs can function as a power fuse in eg., battery connection (Polyswitch, Multi-fuse). They reset themselves when they short circuit or when the load is removed. Available in values from the 1A up to around 10A. A standard PTC resistor works in the opposite way from an NTC resistor (Positive Temperature Coefficient), ie., the resistance increases as the temperature increases.