Electrical Engineering is wide but the two major aspects are electrical and electronic. My recent post on zappl was about the Introduction of Paper Pencil Circuit

During my study I understood drawing with a pencil on paper is the simplest and a very easiest way in establishing a graphitic circuitry particularly in solvent-free manner.

Overview

Following the recent development of paper-based electronics, the clearer understanding of this innovation needs to be revealed for the benefit of my followers and the entire #steemit community. Firstly, let me explain some element which is in use when referring to Paper Pencil Circuit.

Graphite: This is an allotrope of carbon for those familiar with the chemistry we understand that carbon belongs to group 4 and usually carbon is a non-conducting element.

This element can be found on earth in the form of minerals in metamorphic rocks like marble and gneiss. Being layered, it can be deposited on a rough surface by the process called Exfoliation using a gentle slight force. With this little explanation together with its black colour, this must have impressed early literate to use a piece of Graphite as a tool to make impressions on surfaces. This is the beginning of invention of Pencil in the 16th century. The pencil we see this day is essentially nanocomposite of graphite with intercalated clay particles and sometimes containing a tiny amount of wax. It is the amount of graphite to clay content that determines the category of pencil, but pencil category is of two types which are ( H and B).

The H connote the hardness or higher clay while the B connote the blackness which is due to higher graphitic content.

Paper is another tool or element we will be considering and this material forms an ideal surface for the exfoliation of graphite particles from pencils through a process called Mechanical Abrasion which lead to a black deposit i.e. Pencil Trace.

Do you know that the black deposit (Pencil Trace) contains interconnected numerous graphene layers whic makes it reasonably conducting in spite of the introduction/presence of insulating clay particles.

There are different types of paper that support the black deposit. Some of the paper like xerox paper, filter paper, weighing paper and glossy paper has different roughness and when the roughness characteristics is greater, larger graphene layers get deposited with small interconnectivity among the graphitic deposits of the pencil trace. Paper trace is unsupported by glossy paper due to no abrasion effect from the smooth surface, therefore paper surface with optimal roughness between (1-5 micrometer) are required to make a pencil trace.

We need to have these understanding, different grades of papers would be useful for different kinds of applications and a specific device application will definitely need a particular type of paper substrate.

In this article we shall be looking at the paper as platform for writing flexible electronic circuitry.

Graphite Resistors on Paper

What is a Resistor? This is a component with passive electrical terminal that implements electrical resistance as a circuit element.
Wikimedia For Circuit Below: By: Cyril Mechkov-- Ohm's Law Graphite Led

A pencil trace on paper is a graphitic resistor and the resistance varies, with its physical dimensions, length, wide, and thickness.

Application of Paper Pencil Circuit

In my review i discovered that there are many literature examples illustrating the use of pencil drawing in various devices, even therisre electrical video displaying the methods and different designs. Let's look at some of this applications.

• Paper Pencil Circuis a Conducting Track

The conventional wires or pads as the case may be are made out of metallic elements like Aluminium or Copper.

By drawing with a pencil on paper you have make graphitic paths, which are essentially conducting track and this can be utilized in fabricating paper based functional devices like Ultraviolet Sensor and Microfluidic Sensor.

For UV sensor paper-pencil circuitry ,innovation it has been cost-effective effective manner. The graphitic tracks were made through pencil drawings to be employed as electrodes pads on paper.

• Paper Pencil Circuit as Sensing Element

Pencil-traces have also been employed as sensing elements for
mechanical force,, chemicals and even glucose, leading to the
fabrication of piezoresistive and chemiresistive and biosensor.

On Biosensor, the demand for developing simple and inexpensive analytical devices is on the rise fobiosensingio sensing in diabetics. It was discovered that Santhiago and Kubota have developed
a simple approach for glucose biosensing by employing paper
based analytical devices using graphitic electrode.

• Paper Pencil Circuit as an Energy Storage Devices

Knowing that most stored charge can be traced to batteries and supercapacitors majorly all electrochemical energy storage devices store energy by two processes which are Faradaic and non-Faradaic. Penc, l drawing on the other hand, has also made an entry as an electrode material in the fabrication of these devices.

• Paper Pencil Circuit as Passive and Active Electronic Devices

The black deposit on paper have also been used as a resistor element in fabricating active devices like transistor (Field Effect Transistor) and passive devices Filter (RF filter)

KeyNote

Sequel to above application and the knowledge pass on Graphitic circuitry on paper, the pencil drawing is rather simple, inexpensive and even solvent-free technique. As a result of light weight, chemical stability and resistance to heat and radiation, the attraction in fabricating different kinds of active and passive circuits become the top story everywhere.

However, as paper is hygroscopic, a certain amount of moisture may help in giving rise to ionic currents, which will then affect the electrical properties of the pencil-trace on paper. The solution to this problem is by laminating the pencil trace on paper between plastic films in order to obtain stable device performance

Thank you for reading.

Find more information check below references.

1. Pulp & Paper Resources & Information Site: Grade(Types) Of Paper

2. M. S. Dresselhaus and G. Dresselhaus, Adv. Phys., 2002, 51,
   1–186.

3. Popular Science Site; When is Carbon an Electrical Conductor by: Adam Weiner

4. PDF Google Scholar; Graphitic Structure by Jonathan Philips & Joe Cordaro

5. Quora Website; Why is Graphite A Good Conductor by Bindu Bindu

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