The above diagram is of a simple dry cell battery — like the ones found in a flashlight. These typically generate a potential of 1-1/2 Volts and have a reserve capacity of about 8 amp hours. The simplest of these batteries has a cathode made from a zinc outer can (1) that is filled with a chemical mix of electrolyte and carbon powder with a gel like layer of Zinc Chloride next to the can. The anode is typically a carbon rod center post. It will have a positive charge. The outer can will be negatively charged. Electrons flow from the can to the post when connected with a wire. The carbon matrix in the can facilitates the electron flow back to the gel which supplies more electrons to the zinc can — and on and on. The battery will supply power as long as the zinc chloride and zinc metal interface is chemically active. The chemistry is the exchange of electrons on a sub-atomic level and the battery is depleted when the chemical reaction is complete. For our purposes, this is a convenient source of electron and we will use it for our simple circuit diagrams to follow.