1-21 If only two capacitors are used: If more than two capacitors are used: CAUTION Capacitors retain an electrical charge. Be sure to discharge all capacitors and circuits containing capacitors before working on them. A more detailed description of capacitors and capacitance can be found in NEETS, Module 2, Introduction to Alternating Current and Transformers. Current Electrons (negative charges) move through a conductor when an electric field is applied. Electron current is defined as the directed flow of electrons from negative to positive. Current is measured in AMPERES (AMP). One amp of current flows when one coulomb (6.28 10^{18} electrons) passes a point in one second. The Ohm's law formulas for current are: