Last Sync: 2022-08-25 09:00:04

Electronics/Cells_and_batteries.md

@@ -5,3 +5,39 @@ tags: [physics, electricity]
 ---
 
 # Cells and batteries
+
+Cells are a [voltage source](/Electronics/Physics_of_electricity/Voltage.md#chemicals-cells-and-batteries) that generate a difference of potential via a positive and negative electrode separated by an electrolytic solution. The electrolytes pull free electrons from one of the materials which creates a positive charge. The other material gains the free electrons creating a negative charge.
+
+> A battery is a combination of two or more cells.
+
+> Cells which cannot be recharged are called **primary cells**. Cells which can be recharged are called **secondary cells**.
+
+## Connecting batteries
+
+Cells and batteries can be connected to each other in electrical ciruits to increase the overall voltage that is produced. There are three main connection types:
+
+- series
+- parallel
+- series-parallel
+
+### Series connections
+
+With series connections we distinguish **series aiding** and **series opposing** configurations.
+
+In the case of series aiding, cells are connected one in front of another with the positive terminal connecting to the negative terminal of the other in a line.
+
+In this configuration the **same current flows through all the cells**. This is represented mathematically as follows ($T$ stands for time):
+
+$$
+I_{T} = I_{1} + I_{2} + I_{3} \\
+$$
+
+The voltage is the sum of the individual cell voltages (represented here as [electrical field](/Electronics/Physics_of_electricity/Voltage.md#distinguishing-voltage-from-electric-field)).
+
+$$
+E_{T} = E_{1} + E_{2} + E_{3} \\
+$$
+
+> Note here we use $E$ instead of $V$. Strictly, $V$ denotes the potential difference whereas $E$ denotes the **electric field**. The electric field is the physical field that surrounds each electric charge and exerts force on all other charges in the field, attracting or repelling them
+
+// TODO: Add image

Electronics/Physics_of_electricity/Voltage.md

@@ -18,6 +18,13 @@ Voltage is the application of this energy. Any form of energy that dislodges ele
 
 > It is important to realise that in this process energy is not 'created', rather there is a transfer of energy from one form to another. The force applied to generate the current is energy in one form that is converted to another form: electrical current.
 
+## Distinguishing _voltage_ from _electric field_
+
+It can be confusing that two different symbols often seemed to be used interchangeably when talking about voltage: $V$ and $E$. However, while they broadly point to the same phenomenon there is a difference in emphasis.
+
+- $V$ stands for volts or voltage conceived purely in terms of the difference in potential between two points: the positive and negative terminals
+- $E$ stands for electric field. This is the field that surround each electric charge and exerts force on all other charges in the field, attracting or repelling them. So it is more the physical process that the volatage represents rather than the numerical representation of the potential between the terminals.
+
 ## Voltage sources
 
 The following are the main sources of voltage: