DC Circuits Study Guide

For the test over dc circuits you should know:

• How to add resistances in parallel and in series
• The five types of emf sources and their function.
• The relative resistances of voltmeters and ammeters and how they are connected in a circuit.
• What electron drift speed is and how it compares to the thermal speed.
• How resistance depends on length and cross-sectional area of a wire.
• How parallel and series connection of cells affects circuit emf and current.
• How to calculate an unknown resistance in a Wheatstone bridge circuit.
• What critical temperature is and how resistance is affected by it.
• What the unit of current is and what it is dimensionally equivalent to.
• Which method of resistance measurement is most accurate.

and be able to:

• draw a simple circuit with batteries and resistors in series or parallel.
• Calculate unknown currents, resistances, battery emf, or voltage drops in a given circuit using Ohm's law and/or Kirchhoff's rules.
• Calculate resistivity, given resistance, length and diameter of a wire.