What are Series Circuits Used for?
Series circuits are most often used for lighting. A common example is a string of classic Christmas tree lights, in which the loss of one bulb shuts off the flow of electricity to each bulb further down the line. However, series circuits can be used for any situation in which a single cable is used to supply power to a number of widely spaced lights or other devices.
A series circuit uses a single cable with multiple resistors on it. As more voltages flow through a series circuit, a more expensive and heavily insulated cable is a must. This allows applications to be made much more cheaply with a single power source and only a single cable. Modern models also include bypasses so the loss of one resistor does not break the circuit. A series circuit also must be able to cope with the sum of all resistances on the circuit. Thus, the voltage must be high enough to compensate for the voltage drop from each resistor.