At various times in our daily lives we come across situations in which we make use of electricity generators, but we are not even aware of it. A very simple example is when we change the batteries in the TV remote control. Therefore, we find electricity generators in various equipment that surround us: ranging from remote control batteries to car batteries.
We conceptualize a generator as a mechanism that transforms mechanical, chemical or other form of energy into electrical energy. Another example of a generator that we can cite is the dynamo. Thus, a generator provides a potential difference ( ddp ), called, in Physics, electromotive force. In the figure above we can see that the batteries are associated in series, that is, we have a series association of generators feeding the battery.
In this case, we are ignoring the internal resistance of the generator. Still in the figure above we see that the batteries are connected so that the positive pole of battery A is in direct contact with the negative pole of battery B.
A basic characteristic of generators is that the electromotive force of a generator is equal to the energy supplied to each unit of load. In this way, the total energy that each of the charge units presents is the sum of the electromotive forces of the two batteries, that is, they can be replaced by a single battery, of electromotive forces E such that E = E A + E B . See figure 2 below:
Figure 2 – Sum of electromotive forces
According to the figure below, we see that apparently the batteries are in opposition, but we can see that the positive pole of one battery is in contact with the negative pole of the other, so that the two batteries drive the current in the same direction. Therefore, we can say that stacks can be associated in different ways. In many electronic devices the batteries can be associated as shown in the figure below:
Figure 3 – Association of generators in other devices
Thus, we can replace the two batteries with a single one, whose electromotive force is the sum of the electromotive forces of the two batteries. If the batteries have internal resistance, just add them up.