What do I need to know to build my own circuits

[selseg]

I know what a capacitor, resistor , variable resistor, diode ,transitor , is and how they work, and some basic calculations on each of them. I know kirchoff, ohms law,etc. My problem is how do I know what and what to put together to get a transmitter or a reciever or amplifier without looking somewhere on the internet where there are schematics.I just want to be able to think it myself and build circuits

 

[berkeman]

A good way to start is to get a couple kits from Radio Shack or another electronics store near you, or from the Internet like this place:

http://www.discounttwo-wayradio.com/customkititems.asp?kc=CP220USXS6P

Kits usually come with the schematic, of course, and a description of how the circuit works. They also make it easy for you to solder up the kit, and start to learn about how to physically build circuits.

It would be good for you to get an introduction to circuits book, if you don't already have one. The intro electronics book that I usually recommend is the Art of Electronics by Horowitz and Hill:

https://www.amazon.com/dp/0521370957/?tag=pfamazon01-20

Putting together some kits while also reading the AoE from cover-to-cover will get you going pretty well on building up your own projects. Have fun!

 

[cmpalmer]

The Art of Electronics is probably the best single volume textbook on electronics out there, but it can be daunting if you are just starting out.

For a good taste of practical circuits, I would recommend Getting Started in Electronics by Forrest Mims (https://www.amazon.com/dp/0945053282/?tag=pfamazon01-20)

The Electronics Project Lab that Radio Shack now sells is also a good starting point. Unlike older project lab kits from them, where every component was mounted on cardboard and connected with spring connectors, the new lab has a large solderless breadboard in the center, multiple voltage points (it's still battery powered, unfortunately) and comes with a large number of discrete parts including a good basic set of analog and digital ICs. The manuals for the project lab are by Mims as well and are essentially the Getting Started in Electronics book divided into projects to be built with the enclosed parts.

When I first started playing around with electronics years ago, I started getting frustrated that the leap from small hobby circuits to useful devices was so large (this was when I was in high school). Soon after that, I got my first computer and the stuff you could do with a few lines of code was more impressive, so I went into computers instead of electronics. Recently I've gotten interested in electronics again due to the rise of cheap microcontroller development systems. With the microcontrollers, you only require minimal electronics circuits (sensors, amps, transistor circuits to switch and control larger currents, etc.) to create really interesting projects. Check out http://arduino.cc"

 

[chroot]

What you're asking for is essentially a degree in electrical engineering. Unfortunately, it's a long (but rewarding) road to go from "What is a capacitor?" to "I've designed an amplifier."

- Warren

 

[cmpalmer]

The analogy that I've used on other forums when similar subjects have come up is comparing electronics to carpentry and construction.

An electrical engineer is akin to an architect - someone who (presumably) knows everything about the design and construction of buildings. Construction techniques, strength of materials, costs, analysis techniques, project management, design and aesthetics, etc.

Not having a degree and formal training in architecture doesn't mean that someone can't take up carpentry and progress in skill at their own pace, say from building a birdhouse kit, to building a shed, to creating beautiful furniture and cabinet work, to building and designing their own houses (as long as they understand the building codes).

An electrical engineer is trained in the math, physics, and "design patterns" for developing electronic devices. It is a demanding degree and, theoretically, once you get the degree you should be comfortable designing anything from an electronic toy, to a power supply, to PC boards with hundreds of surface mount components. At the advanced levels, or with post-graduate work, you would even be able to design and fabricate new integrated circuits and CPUs.

As an electronics hobbiest, you can start with electronics kits that, depending on how closely you study them, will teach you some basic fundamentals of electronics design. You can start with a small set of tools, a parts cabinet, and some good books or websites and design small, interesting, and handy gadgets. Along the way you will develop your skills in construction, debugging, and testing circuits and begin to acquire the basic math skills (V=IR, RC constants, series vs. parallel calculations, digital logic, etc.) and learn the rules of thumb of how to combine useful components and subassemblies to create more complex designs. In other words, you can progress as far as you want to up to a certain point. You aren't likely to be able to build a TV from scratch or even develop a robust commercial product without some formal training, for example. Then again, a weekend carpenter, no matter how skilled, isn't going to design a skyscraper.

As I said before, using microcontrollers like the Arduino that let you abstract a lot of complexity into software and the fact that there are many really easy to use sophisticated devices and subassemblies (accelerometers, GPS on a chip, computer interfaces, Bluetooth boards, computer interfaces, LCD module drives, etc.) means that this is actually a very exciting time to become an electronics hobbiest (or professional).

Here are some good links to things related to this rebirth of hobby electronics:

http://makezine.com"
http://sparkfun.com" - check out their cool selection of sensors, microcontroller tools, components
http://arduino.cc" - mentioned this earlier
http://ladyada.net/make/index.html" - kits, tutorials, and a great forum

 

[selseg]

I am a Materials Engineering student.So far I have done some reasonable amount of mathematics, Some general engineering courses like 'Applied electricity' and 'basic electronics' has given me a little knowledge on electronics.I have looked at the sites you have given to me so far.They are great .I think for now they would be my primary source of information . I have a soldering Iron, breadboard and a few transistors resistors, capacitors. But unfortunately in my part of the world there is no Radio shack and no electronic store where I could get these kits or books so I may have to learn these things the hard way , I don't think I would be able to get 'Art of electronics' too but do you think 'Hughes Electrical technology' could do me any good.Pls give your recomendations

 

[madmike159]

I don't think there is any quick way to go about it. Try buying a book, I can't really recommend any but mine is called Electronics Explained which i got from college. If you learn about simple circuits, equations for them and how they work then you can use them together to make more complex things.