Circuit diagram
Also called Circuit schematic, Schematic diagram
A circuit diagram, or schematic, represents a circuit by drawing each element as a standard symbol joined by lines standing for wires. It records which elements are electrically connected, not where they physically sit on a bench.
The CED calls these circuit schematics and defines them as representations used to describe and analyze electric circuits (11.2.A.4, in both AP Physics 2 and AP Physics C: Electricity and Magnetism). The line that follows is the one worth holding onto: the properties of an electric circuit depend on the physical arrangement of its constituent elements. A schematic is a claim about arrangement, so redrawing one carelessly changes the physics.
The symbol set is printed in the CED, and the two courses print different lists. AP Physics 2 shows seven: battery, bulb, switch, capacitor, resistor, ammeter, voltmeter. AP Physics C: E&M shows those same seven plus the inductor, eight in all, because inductors exist in that course and appear nowhere in AP Physics 2. In both, a variable element is marked by a diagonal strikethrough arrow across the standard symbol.
One boundary statement governs every diagram you will meet: unless otherwise specified, all circuit schematic diagrams will be drawn using conventional current.
Reading a diagram is mostly a question of tracing paths. Two elements with no junction between them are in series and carry the same current; two elements bridging the same pair of nodes are in parallel and share a potential difference. A bend in a wire is not a junction. The reduction itself belongs to the series and parallel guide, and the two rules that let you solve what you cannot reduce are Kirchhoff's loop rule and the junction rule.