CURRENT ELECTRICITY
CURRENT ELECTRICITY
Current electricity is defined as an electrical charge in motion. It consists of a flow of negatively charged electrons from atom to atom through a conductor in an electrical circuit. The external force that causes the electron current flow of electric charge is called the electromotive force (emf) or voltage.
The electromotive force (emf) or voltage, which is explained by Ohm law, is created by a battery which consists of one positively charged and one negatively charged terminal. The negative terminal has an excess of electrons while the positive terminal has a deficiency of electrons.
When a conductor, in this case an electric light bulb, is connected to the two terminals of the battery, a flow of electrons occurs and produces magnetic fields and an electric field. The positive terminal of the battery has a shortage of electrons and thus attracts electrons from the conductor. The negative terminal has an excess of free electrons to move, which repels electrons into the conductor.
There are two different types of current in widespread use today. They are direct current, abbreviated DC, and alternating current, which is abbreviated AC.
Direct current can come from multiple sources, including batteries, solar cells, fuel cells, and some modified alternators. DC power can also be “made” from AC power by using a rectifier that converts AC to DC. Direct current (DC) power, as you may see from the name, is a linear electrical current—it moves in a straight line.
DC power is far more consistent in terms of voltage delivery, meaning that most electronics rely on it and use DC power sources such as batteries. Electronic devices can also convert AC power from outlets to DC power by using a rectifier, often built into a device’s power supply. A transformer will also be used to raise or lower the voltage to a level appropriate for the device in question.
Alternating current, abbreviation AC, flow of electric charge that periodically reverses. It starts, say, from zero, grows to a maximum, decreases to zero, reverses, reaches a maximum in the opposite direction, returns again to the original value, and repeats this cycle indefinitely. The interval of time between the attainment of a definite value on two successive cycles is called the period, the number of cycles or periods per second is the frequency, and the maximum value in either direction is the amplitude of the alternating current.
Low frequencies, such as 50 and 60 cycles per second (hertz), are used for domestic and commercial power, but alternating currents of frequencies around 100,000,000 cycles per second (100 megahertz) are used in television and those of several thousand megahertz in radar or microwave communication. Cellular telephones operate at frequencies of about 1,000 megahertz (1 gigahertz).
Electrical Components
A simple electrical circuit consists of resister, capacitors, inductors, transistors, diodes and integrated circuits. These basic electronic components are connected by conductive wires. Current can easily flow between these wires in order to put electrical components in working conditions.
- Capacitor
Working principle of a capacitor is same like a battery. It is used for the storage of electrical charge. Some circuits are designed in a way, they don’t get energy directly from DC source, DC source first charge the capacitor and output we get is basically the energy given by the capacitor.
Capacitors come in a number of forms, but most common forms are Ceramic Disc and Electrolyte. The capacitance of a capacitor is measured in microfarad and is denoted by μF.
- Diode
- A diodeis a component that allows the current to flow in one direction only. It mainly consists of anode and cathode. Current will only flow when a positive voltage is applied to the anode side and negative voltage is applied to the cathode side. Current won’t flow in reverse order.
- Light Emitting Diode (LED)
LEDs are just like bulbs except that they are extremely reliable. You can find them on practically every appliance in your home that features some kind of an indicator light. A typical LED bulb can last decades with no sign of dying.
- Transistor
Transistors are used to build complex electrical systems, such as amplifiers for instance. A simple way to understand transistors is to think of a switch. A basic switch has an “on” and an “off” state. These are controlled by the position of the switch, which is changed manually.
5. Integrated Circuit (IC)
Integrated circuits are electrical components that combine, or integrate, numerous electrical components, including the ones that were previously mentioned. One IC can act like a transistor while another IC can act like a resistor.An IC is like a ready-made chip that you can use to complete the project you want to build without having to use lots of single transistors or capacitors. As you upgrade from using basic components to integrated circuits, you will find that it is almost always easier to use ICs for your entire project than using individual components.
6. Inductors: These are passive components that store energy in form of a magnetic field. An inductor simply consists of a coil of wire wound around some kind of core. The core could be a magnet or air. When current passes through the inductor, a magnetic field is created around it. The magnetic field is stronger if a magnet is used as the core.
7. Resistor
It is fairly easy to assume that a resistor, as the name suggests, will resist electricity that flows through it, and you would be correct in that assumption too! Any situation that demands the flow of current to be controlled at a desired level will require a resistor.
Resistor Color Code Chat
| Ring Colour | Significant numeral | Multiplier | Tolerance | TCR, Temperature coefficient | |||||
|---|---|---|---|---|---|---|---|---|---|
| Name | Code | RAL | Percent [%] | Letter | [ppm/K] | Letter | |||
| None | – | – | – | – | ±20 | M | – | ||
| Pink | PK | 3015 | – | ×10−3 | ×0.001 | – | – | ||
| Silver | SR | – | – | ×10−2 | ×0.01 | ±10 | K | – | |
| Gold | GD | – | – | ×10−1 | ×0.1 | ±5 | J | – | |
| Black | BK | 9005 | 0 | ×100 | ×1 | – | ±250 | U | |
| Brown | BN | 8003 | 1 | ×101 | ×10 | ±1 | F | ±100 | S |
| Red | RD | 3000 | 2 | ×102 | ×100 | ±2 | G | ±50 | R |
| Orange | OG | 2003 | 3 | ×103 | ×1000 | ±0.05 | W | ±15 | P |
| Yellow | YE | 1021 | 4 | ×104 | ×10000 | ±0.02 | P | ±25 | Q |
| Green | GN | 6018 | 5 | ×105 | ×100000 | ±0.5 | D | ±20 | Z |
| Blue | BU | 5015 | 6 | ×106 | ×1000000 | ±0.25 | C | ±10 | Z |
| Violet | VT | 4005 | 7 | ×107 | ×10000000 | ±0.1 | B | ±5 | M |
| Grey | GY | 7000 | 8 | ×108 | ×100000000 | ±0.01 | L (A) | ±1 | K |
| White | WH | 1013 | 9 | ×109 | ×1000000000 | – | – | ||