Schematic

Hi Roger,

When you first start with electronics things which some people think are trivially obvious are not as a newbie, don't feel disheartened by this, it'll get easier with time, the key thing is to keep at it and, as you have done here, ask for help! Do you have an example of a schematic which you are struggling to understand? If you are looking at something really complex, maybe take a step back and look at some more straightforward designs first, then when you are comfortable with those, move on to the more complex.

The good news is, you're in the right place to find people to help you learn, element14 is full of knowledgeable people who are willing to help people learn!

Best Regards,

Rachael

Rachael

I don’t have a specific schematic as I get lost with anything but the most basic circuits. I can build simple circuits and very much enjoy this, however anything more than lighting a LED I get very confused where positive ends and negative takes over when all the lines are joined and the same colour. I was thinking that if the schematic was colour coded it might help me understand when I am not understanding it.

Many thanks

Roger

Roger,

The key to understanding electronics is to study the basic rules or laws to which all electronics must follow.  These laws (Ohm's law to start with) help you better understand the flow of electricity in a circuit.  These laws can help you transform larger, more complex circuits down into simpler and more understandable blocks.  Another useful learning method is to use a simulator to build and test circuits.  I use LTspice (free download).  In this simulator, you can easily model circuits and observe the voltages and currents, which will allow to reinforce your understanding of the laws and formulas.  Be patient, learn and repeat lessons to build your knowledge and of all things, remember to enjoy the process.  Find fun ways to try new things, like buying and building simple kits.  Experiment with these kits (either on a simulator or by physical modifications) to increase the knowledge.

Have fun,

Gene

Hi Roger,

Element14 has an excellent series on basic electronics called the Learning Circuit.  Have you looked at that? The Learning Circuit

It really helps to understand the basic circuit elements before you try to tackle schematics. 

Ralph

Ralph

it appears no matter how many times I say it that no one is understanding that I really struggle understanding schematic drawings. I have watched many many schematic turorials and still don’t get it. I have also watched The Learning Circuit tutorials and still don’t get it.  I’m ok with basic schematics and can build simple one dimensional circuits but get confused when the circuits get larger. I can’t get my head around where positive ends and negative starts. I know this is really simple to you and must be frustrating that I don’t get it but that is how it is.

If only someone would be kind enough to colour code a schematic drawing to help me understand.

Many thanks

Roger

Hi Roger,

In conjunction with all the other excellent techniques mentioned, familiarity over time will make you recognise portions because they will look like patterns you've seen before.

Unless it is a very poor quality schematic, most people will try to draw their schematics in some well-known styles.

This web link 101-200 electronic circuits is quite good, it has lots of small circuits to gain a quick appreciation of what types of circuits will achieve certain tasks.

There is also 1-100 electronic circuits and 100 IC circuits and 50 555 circuits, they are all useful.

So, for example, here are some random snippets from there:

At a glance, it is possible to tell this is a 'H-bridge' circuit, due to the shape looking like a H. It is used to switch power in either direction. It could have been drawn totally different, but people don't do that - they try to draw it in this style. It becomes an easy pattern to recognise in a larger circuit. Also without any labels, by convention it is possible to guess that the top line is a positive supply rail, and the lower is 0V. This convention wouldn't be assumed when constructing the circuit (since then precision about it is required), but it can be initially assumed when trying to guess what a schematic does.

Even though this is just part of a circuit, it is instantly recognizable as something that will pulse and flash LEDs in a sequence. This is because the 555 is a well-known chip for generating a single or stream of pulses, and the 4017 is well-known to convert an input pulse stream into ten outputs in sequence.

The circuit above can be assumed to be some sort of amplifier, with two stages, since that's a normal use of a transistor. It look designed for amplifying AC signals, since there are capacitors on the input and output that would block DC.

Anyway, these are just some examples, there are many more sub-circuits like these to explore.

Is there an example of the type of color-code you mean?

I've tried in the past to color-code some wires, but I've only found it usable for very small circuits, such as this one:

It can sometimes look fine, but although there are three black lines at the bottom, they are actually separate wires that are not electrically connected, they are connected to MOSFETs. So the color code can get confusing too if done in this way (and there are not enough easy-to-identify shades for most circuits, to have one shade per net).

This circuit uses red to indicate positive, and the three black lines are 'kind of' negative, but they are all different negatives. The left black line is a permanent negative, and the other two are switched negatives. It would be hard to convey this meaning with separate colors, but can be explained in a text explanation of the circuit, or perhaps by recognizing the pattern of two MOSFETs and resistor as shown.

I prefer when circuit diagrams look like this; here the section is identified, it is clear that it is the power supply sub-circuit that is part of a larger circuit, because it has its own box and title, within a larger schematic sheet. Do you mean this dashed box ought to be shaded in a single color, so that the sub-circuit is identified by color?

Hi Roger,

I think part of the problem is understanding precisely what you are asking for.  I know that might sound strange.  I'm not sure what you mean by "where positive ends and negative starts".  I think that we might be struggling with how to color code a schematic for you.

I'm going to be offline for a while, but if you can explain exactly what you need,  I'm sure someone could help.  It really would be good if you could provide an example of a schematic you don't understand as a starting point.  And indicate how you would want color coding applied to that schematic.

Ralph

Hello Roger,

I think these links may be very, very useful for you:

How to Read a Schematic - Sparkfun

Skill Builder: Reading Circuit Diagrams - Make

Luis

Hi Roger,

I am slightly younger than yourself.

A good way to approach complex schematics is to create a block diagram view and then look at each section as it relates to the next block. This approach gives you a roadmap to follow as you work through the details of each block.

DAB