useful info [How Electromotive Force Works]

The Arduino Introduction

What is Arduino?

Arduino is an open-source electronics platform based on easy-to-use hardware and software. Arduino boards are able to read inputs - light on a sensor, a finger on a button, or a Twitter message - and turn it into an output - activating a motor, turning on an LED, publishing something online. You can tell your board what to do by sending a set of instructions to the microcontroller on the board. To do so you use the Arduino programming language (based on Wiring), and the Arduino Software (IDE), based on Processing.

Over the years Arduino has been the brain of thousands of projects, from everyday objects to complex scientific instruments. A worldwide community of makers - students, hobbyists, artists, programmers, and professionals - has gathered around this open-source platform, their contributions have added up to an incredible amount of accessible knowledge that can be of great help to novices and experts alike.

Arduino was born at the Ivrea Interaction Design Institute as an easy tool for fast prototyping, aimed at students without a background in electronics and programming. As soon as it reached a wider community, the Arduino board started changing to adapt to new needs and challenges, differentiating its offer from simple 8-bit boards to products for IoT applications, wearable, 3D printing, and embedded environments. All Arduino boards are completely open-source, empowering users to build them independently and eventually adapt them to their particular needs. The software, too, is open-source, and it is growing through the contributions of users worldwide.

Why Arduino?

Thanks to its simple and accessible user experience, Arduino has been used in thousands of different projects and applications. The Arduino software is easy-to-use for beginners, yet flexible enough for advanced users. It runs on Mac, Windows, and Linux. Teachers and students use it to build low cost scientific instruments, to prove chemistry and physics principles, or to get started with programming and robotics. Designers and architects build interactive prototypes, musicians and artists use it for installations and to experiment with new musical instruments. Makers, of course, use it to build many of the projects exhibited at the Maker Faire, for example. Arduino is a key tool to learn new things. Anyone - children, hobbyists, artists, programmers - can start tinkering just following the step by step instructions of a kit, or sharing ideas online with other members of the Arduino community.

There are many other microcontrollers and microcontroller platforms available for physical computing. Parallax Basic Stamp, Netmedia's BX-24, Phidgets, MIT's Handyboard, and many others offer similar functionality. All of these tools take the messy details of microcontroller programming and wrap it up in an easy-to-use package. Arduino also simplifies the process of working with microcontrollers, but it offers some advantage for teachers, students, and interested amateurs over other systems:

• Inexpensive - Arduino boards are relatively inexpensive compared to other microcontroller platforms. The least expensive version of the Arduino module can be assembled by hand, and even the pre-assembled Arduino modules cost less than $50
• Cross-platform - The Arduino Software (IDE) runs on Windows, Macintosh OSX, and Linux operating systems. Most microcontroller systems are limited to Windows.
• Simple, clear programming environment - The Arduino Software (IDE) is easy-to-use for beginners, yet flexible enough for advanced users to take advantage of as well. For teachers, it's conveniently based on the Processing programming environment, so students learning to program in that environment will be familiar with how the Arduino IDE works.
• Open source and extensible software - The Arduino software is published as open source tools, available for extension by experienced programmers. The language can be expanded through C++ libraries, and people wanting to understand the technical details can make the leap from Arduino to the AVR C programming language on which it's based. Similarly, you can add AVR-C code directly into your Arduino programs if you want to.
• Open source and extensible hardware - The plans of the Arduino boards are published under a Creative Commons license, so experienced circuit designers can make their own version of the module, extending it and improving it. Even relatively inexperienced users can build the breadboard version of the module in order to understand how it works and save money.

A 1000W INVERTER Circuit

what is a DIAC? DIAC application

A DIAC is a full-wave or bi-directional semiconductor switch that can be turned on in both forward and reverse polarities.
The name DIAC comes from the words DIode AC switch. The DIAC is an electronics component that is widely used to assist even triggering of a TRIAC when used in AC switches and as a result they are often found in light dimmers such as those used in domestic lighting. These electronic components are also widely used in starter circuits for fluorescent lamps.
Although the term is not often seen, DIACs may also be called symmetrical trigger diodes - a term resulting from the symmetry of their characteristic curve.
DIACs come in a variety of formats. As discrete components they may be contained in small leaded packages, they can be obtained in surface mount packages, in large packages that bolt to a chassis, or a variety of other packages. As they are often used as a DIAC TRIAC combination, they are often integrated into the same die as a TRIAC.

DIAC symbol

The DIAC symbol used to depict this electronic component in circuit diagrams can be remembered as a combination of what may appear to be two diodes in parallel with each other but connected in opposite directions.

DIAC circuit symbol

Owing to the fact that DIACs are bi-direction devices the terminals cannot be labelled as anode and cathode as they are for a diode. Instead they may be labelled as A1 and A2 or MT1 and MT2, where MT stands for "Main Terminal."

DIAC operation

 

DIAC circuits use the fact that a DIAC only conducts current only after a certain breakdown voltage has been exceeded. The actual breakdown voltage will depend upon the specification for the particular component type.

When the DIAC breakdown voltage occurs, the resistance of the component decreases abruptly and this leads to a sharp decrease in the voltage drop across the DIAC, and a corresponding increase in current. The DIAC will remain in its conducing state until the current flow through it drops below a particular value known as the holding current. When the current falls below the holding current, the DIAC switches back to its high resistance, or non-conducting state.

DIAC voltage- current characteristic

DIACs are widely used in AC applications and it is found that the device is "reset" to its non-conducting state, each time the voltage on the cycle falls so that the current falls below the holding current. As the behaviour of the device is approximately equal in both directions, it can provide a method of providing equal switching for both halves of an AC cycle, e.g. for TRIACs.

Most DIACs have a breakdown voltage of around 30 volts, although the exact specifications will depend upon the particular type of device.. Interestingly their behaviour is somewhat similar to that of a neon lamp, although they offer a far more precise switch on voltage and thereby provide a far better degree of switching equalisation.

DIAC applications

One of the major uses of DIACs within TRIAC circuits. TRIACs do not fire symmetrically as a result of slight differences between the two halves of the device.

The non-symmetrical firing and resulting waveforms give rise to the generation of unwanted harmonics – the less symmetrical the waveform the greater the level of harmonic generation.
DIAC TRIAC combination To resolve the issues resulting from the non-symmetrical operation, a DIAC is often placed in series with the gate. This device helps make the switching more even for both halves of the cycle. This results from the fact that the DIAC switching characteristic is far more even than that of the TRIAC. Since the DIAC prevents any gate current flowing until the trigger voltage has reached a certain voltage in either direction, this makes the firing point of the TRIAC more even in both directions. In view of their usefulness, DIACs may often be built into the gate terminal of a TRIAC.

Summary

DIACs are a widely used electronic component. The chief application of DIACs is for use in conjunction with TRIACs to equalise their switching characteristics. By equalising the switching characteristics of these TRIACs, the level of harmonics generated when switching AC signals can be reduced. Despite this, for large applications, two thyristors are generally used. Nevertheless the DIAC / TRIAC combination is very useful for lower power applications including light dimmers, etc.

Single phase voltage means voltage between line and neutral. So it is a 220 volt which is approximate value.

But in power system genreally ratings are line to line so in 3 phase system 440 is line to line Rms voltage which is obtain by multiplying a factor of 1.732.

That is basic relation between line and phase voltage.

Basic Armature Design

An armature (pictured on right) has a continuous series of windings from each bar on the commutator, which loop around the iron stack teeth and connect to the next bar on the commutator. The winding continues to loop all the way around the armature in the same manner. Loops are either single or parallel conductors (wires), and can circle any number of times around the stack teeth (called turns in a coil). The wire can vary in gauge as is required for the design of the motor. Each wire is insulated with an enamel coating, isolating it from every other wire in the loop, and only terminates at a commutator bar. The turns in every coil wrap around the iron stack to create an electro-magnet. When energized, an electro-magnetic field is generated in the motor armature. This EM field inter-acts with the magnetic fields of the permanent magnets in the motor (in the case of a permanent magnet motor) or with the electro-magnetic field created by the stator (in the case of a universal motor). These magnetic forces work to attract each other, inducing a torque on the armature shaft, causing it to turn.
If a motor is driven too hard for its environment and temperatures are allowed to rise beyond the thermal limits of the insulation, it is possible for the insulation on the wires to break down and short together, or short to the armature stack. If windings are shorted together, the electro-magnetic fields cannot be created for that coil, causing the motor to run erratically or fail all together.