Resistors in Series and in Parallel

There are two ways arranging resistors, series circuits and parallel circuits.


In a series circuit, the resistors are arranged in a chain, so the current has only one path to take and is the same through each resistor. The total resistance is equal to the sum of the resistances:


In a parallel circuit the resistors are arranged with their heads connected together, and their tails connected together.


The current breaks up and flow among each different branch through the resistors and re-combining when the branches meet again. The voltage through each parallel resistor is the same. The total resistance is reduced and is given by the relationship:


The basic electronic components

When building electronic circuits, you will need to become familiar with the basic electronic components including resistors, capacitors, diodes, transistors, and integrated circuits. These components are the bread and butter of most electronic projects. Here is a brief overview of the functions of each of these basic electronic components.


The symbol of  a resistor in schematic diagrams is:


The resistance is an electrical/electronic component which is used in various circuits for controlling the current flow. The unit of electrical resistance in the International System of Units (SI) is the Ohm, which is denoted by (Ω) and got the name from the German physicist Georg Ohm (Georg Ohm). Georg Ohm’s law formulated Ohm, which states that the resistance (R) of an object can be calculated by dividing the potential difference (V) applied to the edges of the object to the current intensity (A) that is flowing.

Mathematically is denoted as:  R = V / I


R: Resistance displayed by the object (in ohms)

V: The potential difference / voltage applied to the ends of the object (in volts)

I: The intensity of current flowing through the object (in amperes)



A breadboard is a reusable construction base for prototyping of electronics and is used to build and test circuits. It’s a quick and easy way to create temporary prototypes and experimenting before finalizing your circuit design.

Prototyping is the process of evaluating an idea, creating a preliminary model of a circuit. This is one of the most common usages of breadboards. If you are not sure how a circuit will respond under a given set of parameters, it is better to create a prototype and try it.

For beginners to electronics and circuits, breadboards are often the best place to start. This is the real beauty of breadboards – can manipulate both the simplest circuit, and very complex circuits. If your circuit current exceeds the breadboard, you can expand your circuit connecting other breadboard circuits to manipulate all sizes and complexity.

Another common usage of breadboards is to try new components, such as integrated circuits (ICs).

A typical breadboard is shown below:




The electrolytic capacitor is one type of capacitor which the plate used is made of ionized liquid form preparations. They usually have larger capacitance in proportion to their volume than do other types of capacitors. They are valuable regarding use in high current circuits and low frequencies. Specifically, their use in power supplies as filters for filtering the voltage output of a ballast circuit is very common. Electrolytic capacitors have high capacitance and allow us to construct filters with very low cut-off frequencies. Finally to be mention that the electrolytic capacitors are polarized and must be careful when connecting the polarity will be destroyed otherwise. In practice the positive pole of the cell is greater and the body of the capacitor, the negative pole is determined by a gray or white stripe along its length.

The typical capacitor is shown in the image below:



Diode LED

A LED is presented as:


LED, Light Emitting Diode, is called a semiconductor that emits a narrow-spectrum light when electrical voltage is granted at the proper bias direction (forward-biased).

The color of the emitted light depends on the chemical composition of the semiconductor material used, and can be ultraviolet, visible or infrared. The wavelength of the light emitted, and therefore its color, depends on the energy gap of the material used to generate the contact P-N.

P = material impregnated with recipients (Deficit Electron)

N = material impregnated with donors (Surplus Electron)


IC – Integrated Circuits 

In electronics, a printed circuit (also known as a microcircuit, microchip, chip, silicon chip) is a micrograph of an electronic circuit, which is usually consist of semiconductor materials as well as passive components.

Integrated circuits was able to be manufactured after experimental discoveries showing that semiconductor elements could perform the functions of vacuum tubes and by technological progress in the field of manufacturing semiconductor elements occurred mid-twentieth century. The integration of a large number of tiny transistors on a thin silicon chip has very significant improvement over the manual assembly of vacuum tubes and discrete electrical components.

The opportunity provided by the integrated circuits for mass production, adding further complexity, reliability and significant cost savings contributed to the rapid dissemination displacing the vacuum tubes and discrete circuits. The significant reduction in costs has been made possible because all data is printed using a single photolithography is printed instead of each transistor individually. In 2006, the area of ​​a chip range from a few square millimeters to 250 mm2, with one million transistors per mm2. Their use is widespread in all electrical and electronic devices we are using today.



A transistor is a three-terminal device in which a voltage applied to one of the terminals (called the base) can control current that flows across the other two terminals (called the collector and the emitter). The transistor is one of the most important devices in electronics.



A switch is a mechanical device that can break an electrical circuit, interrupting the current or diverting it from one conductor to another. There are two states to activate the switch, it opens or closes the circuit.

The most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts, which are connected to external circuits. Each set of contacts can be in one of two states: either “closed” (N.C.) meaning the contacts are touching and electricity can flow between them, or “open” (N.O.), meaning the contacts are separated and the switch is not conducting.

As switches get more complex they can both open one connection and close another when activated. This type of switch is called single-pole double-throw switch (SPDT). If you were to combine two SPDT switches into one single switch, it would be called a double-pole double-throw switch (DPDT). This would break two separate circuits and open two other circuits, every time the switch was activated.



An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal, or cathode, and a negative terminal, or anode. Electrolytes allow ions to move between the electrodes and terminals, which allows current to flow out of the battery to perform work.

Batteries are represented in a circuit by a series of alternating lines of different length. There are also additional marking for power, ground and the voltage rating.



Wires are used to connect things together on breadboard. Wire links can be made with single-core plastic-coated wire of 0.6mm diameter. Stranded wire is not suitable because it will crumple when pushed into a hole and it may damage the board if strands break off.