A circuit is a pathway where electricity can flow through a closed path from the negative (cathode) to the positive (anode) end of a power source. Elements in a circuit can either supply or expend energy. Energy is measured in Joules (J). Suppliers of energy are called sources; they provide a voltage, or charge electrons with energy. The number of electrons flowing in a circuit is called a current, measured in Amperes (A). A common voltage source is a chemical battery, which is an example of a direct-current power source (DC). It provides electrons with a fixed amount of energy (i.e. a fixed voltage) through a chemical reaction within a battery. Resistance is a value that describes how easy for electrons to move in a material when voltage is applied. Resistors are devices that can be added to the circuit to impede current flow. | A circuit is a pathway where electricity can flow through a closed path from the negative (cathode) to the positive (anode) end of a power source. Elements in a circuit can either supply or expend energy. Energy is measured in Joules (J). Suppliers of energy are called sources; they provide a voltage, or charge electrons with energy. The number of electrons flowing in a circuit is called a current, measured in Amperes (A). A common voltage source is a chemical battery, which is an example of a direct-current power source (DC). It provides electrons with a fixed amount of energy (i.e. a fixed voltage) through a chemical reaction within a battery. Resistance is a value that describes how easy for electrons to move in a material when voltage is applied. Resistors are devices that can be added to the circuit to impede current flow. |