As explained earlier DC are direct current and there are many sources of DC and ways to generate it.
There are basically six ways to generate electrical energy which are chemical energy, mechanical energy,heat energy and solar energy.
Sources Of Direct Current.
1.DC from chemical energy.
Direct electricity is produced from chemical energy through the use of cells and batteries.A cell is a device that converts chemical energy into electrical energy.
A cell consists of two unsimilar metals dipped into a solution which can be acid,salt or base.This metals are known as electrodes and the
Solution is known as electrolyte.
The positive electrode is known as the anode,the negative electrode is the cathode.
A simple cell consists of a copper rod and a zinc plate dipped into container filled with dillute sulphuric acid. when the copper and zinc rods are connected to a bulb it lights up due to the motion of DC.
2.DC from heat energy.
We can show that heat energy can be converted into DC by means of a thermocouple.A thermocouple is made up of two dissimilar metals joined together in parralel.when one junction is placed in ice and the other placed in hot water, electricity flows due to temperature difference.
The voltage produced is very small and can be detected with a multimeter.
3.DC from solar energy.
Solar energy are use to convert ultravoilent and light energy into electricity.
When light falls on a photo sensitive surface like sillicon, potassium and alkaline metals(metals that becomes base when dissolved in water.) valence electrons at the surface is ejected and that constitutes electricity.And this phenomenon is known as photoelectricity and discovered by Lenard in 1902.
Materials that converts light to electricity are called solar cells,and they are made up of cathode and an anode.The anode serves as a mere connector,while the metal is the cathode.
Solar cells are use in street lights,space satellite,inverters and it can be use to power up a big village.
4.Mechanical energy.
This can be achieved by converting mechanical rotation into electricity by means of a DC motor or Dynamo.
When an insulated copper wire is wound on a soft iron core known as amarture and then rotated at high speed in a strong magnetic field, magnetic field pulls out electrons in the coil and then produces electricity.
The amount of voltage produced depends on the speed of the armature,the number of turns and the magnetic field strength.
The rotation can be provided by burning fuel or water to form steam an them converted into rotation by means of a piston.
The type of current produced is not a pure DC because of unsteady level due to brush,but can be corrected with diodes.
