Grade 12Electric Current

Why do we need to connect a series resistor with a battery in a charging circuit to charge the battery?

Abdul Jawwad

6 Years agoGrade 12

2 Answers

Arun

Approved Tutor Answer6 Years ago

I assume that this relates to simple lead/acid batteries and their chargers.

Very little control has to maintained but there has to be some. It is best to design it in with properly rated components, but you can take short cuts if you don’t care ab0ut quality and reliability.

The excess voltage of the charger over the battery voltage results in the charging current. Consider this… the battery is designed to supply very large currents, it absolutely has to have very low internal resistance.

Remember Ohm’s Law? Current in a circuit is calculated by **dividing** voltage by resistance. You should know where this is leading…

The charger needs protecting!

Without a series resistor, there is a good chance that it will destroy itself. The current will be limited only by the quality of the parts from which it is constructed. They do have resistance and will get hot. Transformer windings have resistance, as do rectifiers. Transformer cores will saturate and limit the current supplied.

Rather than abusing these relatively expensive parts the solution is a cheap easily calculated well ventilated series resistor.

Vikas TU

6 Years ago

Dear student

Let us take the examples of a car battery,

To start a car if we need an additional battery then we never add it in series to the one we already have because if we do that then it increases the total output voltage and it increases the risk of sparking and out of the spark plug and thus, increase the risk of the car getting blown to pieces.It is the cells in side the battery that are connected in series to eachother to make up a battery as no one single cell will be able to provide for the power required to start the car. Thus a combination of cells in series, which is also known as a battery, is used to serve the purpose.

Hope this information will clear your doubts about (Electricity).