is with the connections going from the carbon terminal of one cell to the zinc terminal of the next, the total voltage will be three times as much as that of a single cell (3 x 1.5 = 4.5 volts). This is a series arrangement (a series battery). However, the capacity of this arrangement is the same as the capacity of one single cell--only the voltage has increased.
Cells can be connected in an arrangement which is a combination of series and parallel. Figure 10(E) shows a simple parallel-series arrangement--this is equivalent to two batteries of 6 volts each connected in parallel. Figure 10(G) is equivalent to 4-6 volt batteries connected in parallel--and the capacity is that of 3 single cells. Figure 10(I) shows a parallel series arrangement. What is its capacity? 25 x 4 or 100 ampere-hours, driven by an electromotive force of 6 volts.
Any number of e.m.f. sources, dry cells, storage batteries, generators, vacuum tubes, transformers (things you will learn
Fig. 11
all about soon) may be connected in parallel providing they supply under load (drawing current) equal voltages.
Any number of e.m.f. supplies may be connected in series. In fact, any number of A.C. and D.C. voltages may be added and the result will be the sum of all of them at any instant of time.
Before going any further, let us get very clearly in mind the fact that voltage produces current when a path is provided for the current. It is with current flow that we are vitally concerned. It is this that we know as electricity, it is current that works for us and makes possible the wonders of electricity.
All conductors offer some resistance to current flow in a circuit. If there is 1 volt pressure in a circuit and a current of 1 ampere is flowing, the resistance opposing the action of 1 volt is 1 ohm. See Fig. 11. Surely, if the resistance in ohms is greater, the e.m.f. will have less effect and the current will be lowered in value.
