In this tutorial you can learn basic definitions about electronics Such as Electronic, Active Devices, Passive Devices,Current, Direct Current,Alternating Current, Frequency, Voltage, Resistance etc.

Definition of Electronics

Electronics is the branch of science that deals with the study of flow and control of electrons and the study of their behavior and effects in vacuums, gases, and semiconductors, and with devices using such electrons. This control of electrons is accomplished by devices that resist, carry, select, steer, switch, store, manipulate, and exploit the electron.

Types of Electronic Components

There are two types of electronic components. They are active components and passive components.The meaning of these as follows.

Passive Components is the components which Capable to operating without an external power source. Typical passive components are resistors, capacitors, instructor and diodes.
Active Components is the components which Require a source of power to operate such as All types of Includes transistors, All types of integrated circuits, TRIACs, SCRs, LEDs, etc.

Electronic Current and Types of Currents

An electric current is a flow of electric charge one place to another place. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionized gas. The magnitude of the current is determined by the available voltage, and the resistance (or impedance) of the load and the power source. For electronics, current may also be measured in mA (milliamps) – 1,000 mA is 1A. Nano-amps (nA) are also used in some cases. Basically Electronic current can be divided in two types they are Direct Current and Alternating Current.

In Direct Current (DC), The electrons flow in one direction only. Current flow is from negative to positive, although it is often more convenient to think of it as from positive to negative. This is sometimes referred to as “Conventional” current as opposed to electron flow.

In Alternating Current, The electrons flow in both directions in a cyclic manner – first one way, then the other. The rate of change of direction determines the frequency, measured in Hertz(Hz).the simple meaning of hertz cycles per second.

Frequency, Voltage and Resistance

Frequency is the number of times the signal completes a complete cycle in one second is the frequency. and the complete cycle is completed when the AC signal has gone from zero volts to one extreme, back through zero volts to the opposite extreme, and returned to zero. The accepted audio range of the people is from 20Hz to 20,000Hz. The Unit of the frequency is Hertz, Symbol is Hz, old symbol was CPS (cycles per second).

Voltage is the “pressure” of electricity, or “electromotive force” therefore the old term of valtage is E.and measuring unit is Volts and also Symbol is V or U, old symbol was E . When considering a 9V battery,It has a voltage of 9V DC, and may be positive or negative depending on the terminal that is used as the reference. The mains has a voltage of 220, 240 or 110V depending where you live – this is AC, and alternates between positive and negative values. Voltage is also commonly measured in millivolts (mV), and 1,000 mV is 1V. Microvolts (uV) and nanovolts (nV) are also used.

Resistance is the opposition that a substance offers to the flow of electric current. and the unit of resistance is Ohms, Symbol is R or Ω . Resistance is a measure of how easily or with what difficulty electrons will flow through the device. Vary low resistance has in the Copper wire therefore a small voltage will allow a large current to flow. Likewise, the plastic insulation has a very high resistance, and prevents current from flowing from one wire to those adjacent. Resistors have a defined resistance, so the current can be calculated for any voltage. Resistance in passive devices is always positive.