From schematic to breadboard (reality). - Page 1
Forum section: electronics / beginners

author: Mint.
author_rank: Frequent Contributor
timestamp: January 19, 2012, 09:58:43 am
content: Hello everybody,I have got very bad results recently when I have tried to create circuits on breadboards. Eg. Capacitors exploding, burning out components. And I haven't had much success. Now my question is, how do people look at the schematic and transfer it to a breadboard? Any tips or good guides on the internet? Because all I could find was guides on how breadboard are structured and not how to transfer from schematic to breadboard.

author: Bored@Work
author_rank: Super Contributor
timestamp: January 19, 2012, 11:08:30 am
content: patiencefocusattention to detail

author: amspire
author_rank: Super Contributor
timestamp: January 19, 2012, 11:17:35 am
content: You can try using the open source program Fritzing:http://fritzing.org/It matches the schematic to a breadboard layout and a board layout. Definitely worth a try.

author: thilo
author_rank: Regular Contributor
timestamp: January 19, 2012, 11:20:19 am
content: Exploding capacitors? Burning components? How are you powering your circuits? You should use a power supply with current limiting capabilities.

author: Psi
author_rank: Super Contributor
timestamp: January 19, 2012, 11:41:38 am
content: Also, a good tip.Most breadboards have twin power rails available on the top and bottom of the board.I recommendnotusing a single side for both positiveandnegative.Have positive only on the top and negative only on the bottom instead.Otherwise it's far to easy to plug a component into the wrong hole and get + instead of - etc..You also get component legs right next to each other carrying + and - which is just asking for a short.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 19, 2012, 02:40:52 pm
content: I've never been fond of breadboardsYou connect the dumb thing up,& one of the wires falls out.While you are sorting that out,another one breaks off!I much prefer to build things on perf board!That said,the main thing with building anything from a schematic,is to take care that you have everything correct before applying power.The only way you can explode caps is putting electros & tants back to front--still just a care thing.VK6ZGO

author: olsenn
author_rank: Frequent Contributor
timestamp: January 19, 2012, 03:11:31 pm
content: 1) When using a capacitor, check to see if it is polorized (matters which side is more negative than the other). Electrolytics are polarized, and if you connect your ground to the positive side and your +5V to the negative side then it will explode.2) Calculate the power that is being dissipated in your resistors (P=IV). Most through hole resistors you will encounter can only safely handle 0.25 watts of power... many can only handle 0.125 watts. If too much power dissipates through a resistor it will overheat to the point where it will melt.3) As thilo mentioned, get yourself a professional grade power supply with current limiting (not AA batteries or a cheap transformer from RadioShack with a switch to change the voltage in 1.5V increments). A good PSU will cost you a couple hundred dollars, but if you're serious about electronics then it is worth it. Think about it this way: with the money that you would be spending on useless textbooks for your mandatory English class, you could buy yourself a decent power supply that will not only last you a lifetime and save you lots of time, but also save your circuits from being destroyed all because you put a lead in the wrong hole. Also, a good PSU will have a voltage and current readout on it, so that not only it will limit current but also tell you how much is being used; this is my no means a replacement for a multimeter when accuracy is needed, but it will give you an idea of what's going on in your circuit. It's far better than holding your hand over the circuit and plugging it in, waiting to pull it back out if you feel something getting hot!4) Most importantly, double check and tripple check EVERYTHING!!!!

author: David Aurora
author_rank: Frequent Contributor
timestamp: January 19, 2012, 03:14:40 pm
content: If you've got things exploding, the main point I'd make is slow down.First make sure you're familiar with what the marks on the schematic actually mean before you start plugging them in. Polarity of components, units of measurement, voltage ratings of parts and so on. Locate any data sheets you might need. Once you're sure of that, start with some very basic circuits. An LED, a basic single transistor amplifier, stuff like that. Make sure you know how to use your multimeter to measure different areas of the circuit. Then just build up from there to more complex circuits as your understanding of how it all works increases.Going from a schematic to a breadboard/perfboard/PCB usually requires you to have some basic understanding of what is happening electrically. Sure, sometimes a REALLY simple schematic might be possible to copy visually to a perfboard or something, but generally speaking you need to know what the parts are actually doing if you want to convert from a schematic to a layout because they're going to look very different. As a simple example, if you see a triangle with 3 connections representing an opamp that in reality is a rectangular chip with 8 pins, you're in trouble if you don't know how to check the pinout on the data sheet, identify the pins and connect them appropriately on the board.So yeah, basically take it slow and understand the circuit first, then how to move the circuit from a picture to a board will come naturally. That, and what everyone else already said.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2012, 03:27:40 pm
content: Quote from: Mint. on January 19, 2012, 09:58:43 amTake care, check your connections, do it rightMany people think a circuit will work if you do it approximately. That it doesn't matter which way round you put diodes and capacitors, that the base, emitter and collector of a transistor are all equivalent and can be rearranged to suit, that you can connect things to different parts of the circuit if they won't quite reach the proper destination.But this is not true. Circuits only work if you connect themexactlythey way they are drawn. There is no room for nearly the same or almost the same when following a circuit diagram.For example, when your LM317 circuit didn't work you excused yourself by saying you got "confused by the schematic". But you must not try to pretend it wasn't your fault like that. You must take responsibility for your error. The schematic was crystal clear about how things should be connected and you didn't make sure you followed it. You said to yourself "oh, even if I wired it up differently it will still work". But it won't!So the simple answer is to take more care. Follow the connections on the schematic exactly. Check and double check before applying any power. Don't be impatient.As for blowing things up, test your circuits with a 9 V battery. It doesn't have enough power to blow up a capacitor, so at least some components will be safe from mistakes. There is no shame in this. I use small batteries to power my circuits a lot.

author: McMonster
author_rank: Frequent Contributor
timestamp: January 19, 2012, 03:51:38 pm
content: Quote from: vk6zgo on January 19, 2012, 02:40:52 pmThat's the price you pay for being able to change your circuit very quickly. I started with breadboards and they still didn't frustrate me enough to throw them away. Pulling out iron every time you want to make a very small change is a pain in the ass, and it's always good to experiment a lot, like "will that work the same if I put a resistor there?" when you're a beginner.Good quality jumper wiresof different colorscan do a difference. Honestly I've been always using wires from UTP network cables and it worked for me (solid core, not stranded, extremely important!), but recently I started to solder single goldpins at the ends (or goldpin/socket for plugging external microcontroller modules into breadboarded circuitry) with heat shrinks and it's good enough. One evening with a soldering iron and you get reasonable quality jumper wires.As mentioned before, slow down. Double check your connections as you go. Then check all the power rails and polarity again, especially for ICs and capacitors. Make sure you know how the internal connections of the breadboard look like.Also try to think in advance how to arrange components and use a lot of spacing (large or multiple breadboards help). Use small tweezers when working in clusters of wires so you don't pull out those you don't want to when changing position of just a single wire.Those are mostly the rules I use when working with breadboards and I don't have any problems. Nevertheless it's always personal preference that makes the difference at the end, so don't be afraid to experiment, try using a perfboard and see if it works for you.

author: Mint.
author_rank: Frequent Contributor
timestamp: January 19, 2012, 07:56:57 pm
content: Quote from: thilo on January 19, 2012, 11:20:19 amHey at least I'm learning, right?

author: Mint.
author_rank: Frequent Contributor
timestamp: January 19, 2012, 07:58:57 pm
content: Quote from: IanB on January 19, 2012, 03:27:40 pmDon't worry. I learn from my mistakes. It's just that I have never seen the two adjustment resistors connected the way they were, at first I thought that they were a voltage divider, but now I have no idea what they are, but hey! Now it works well!