A printed circuit board (PCB) is the board base for physically supporting and wiring the surface-mounted and socketed components in the most electronics. 

Electronic components are typically placed by machine onto a finished PCB that has solder dabs in place. The PCB bakes in an industrial oven to melt the solder, which joins the connections. Most PCBs are made from fiberglass or glass-reinforced plastics with copper traces. PCBs can be single-layer for simple electronic devices. Printed circuit boards for complex hardware, such as computer graphics card and motherboards, may have up to twelve layers. PCBs are most often green but they can come in any color. 

SCHEMATIC DIAGRAM

A drawing that shows all of the significant components of a circuit, flow process or device. It will use a standard set of symbols.  A schematic, or schematic diagram, is a representation of the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension.

   ETCHING

A selective removal of material from the surface of a PCB by means of the chemical action of an etchant (or etching agent). Etching usually removes the copper areas which are not desired on the finished PCB.

STEPS IN PCB DESIGNING USING MARKER

materials needed:

• paper,pencil,ruler                                                
• ferric chloride
• copper clad/PCB board
• marker
• container/basin
• dry cloth

Step1: Design the Circuit

Using paper and pencil design the layout of the circuit.It is easiest to do do as a top view of the board, and it helps to also have all the different components on hand to help with spacing and placement.

Step2:Transferring the Circuit

Clean the PCB board with dry cloth. After cleaning, Transfer your drawing on PCB board using a pencil to easily erase the mistakes in your drawing.Using the marker trace the design on the PCB.

Step3:Etching

Start off by binding a clean and dry place where you can safely etch the circuit board, preferably outside.Take your first container/ basin and pour the Ferric Chloride into it. Fill the Second container with water.Drop the PCB into the  first container/ basin that contains Ferric Chloride. In about 5-7 minutes you should start to see the copper starts to dissolve away.After about 10-12 minutes the board should be completely etched, at which time you should immediately remove the PCB and drop it into the water in the second container/basin to rinse it and then dry it off on the dry cloth. Using an alcohol remove the marker lines on the PCB board.

Step4:Drilling the PCB board

Use the drill bit to make a hole that the components can fit with designated position.