# A Complete Guide To Basic Electronics.

The aim of this instcutable is to give a crash course in high school physics, by explaining the basics of electronics hopefully it should make it alot easier for beginners to undertake instructables that they never thought they knew how to before.

as a quick start you will need to know :
voltage is measured in volts (V)
and current in amps or amperes (A)

now, Circuits.
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## Step 1: Current and Voltage Fundamentals

Voltage changes throughout a circuit and differs across components. voltage is measured by putting a voltmeter in parallel across a component as pictured below, this is because a voltmeter has infinite resistance and if put in series would break the circuit stopping the flow of electricity.

current (amps) is constant throughout a series circuit and splits in a parallel circuit evenly.
current is measures using an ammeter in series and the placement of the ammeter does not matter as the current is the same anywhere in a circuit. (pictured below)
ysf0822 days ago
Tbus10 months ago

This is a great review for my final exam. I am taking a Basic Electronics home study course (http://www.ciebookstore.com/basic-electronics-cour...) and this instructable covered a lot of what I learned and was a great brush up! Thank you!

mambre2 years ago
Nice and clear instructable, I have only one question about resistors - what is the difference between putting one transistor in series and in parallel in a cercuit? Thanks
nottauser3 years ago
I dropped out of high school in the tenth grade and haven't been able to pursue electronics knowledge except thru instructables and people like You who share what they know.
can you direct me to how to build a circuit for making a turn signal light like the ones that were used in old ford thunderbirds?They would start blinking sequence from the rear center taillights and appear to light in a trailing sequence to the outside edge and repeat.
Such a cool array that I don't know why other cars didnot feature the same arangment for turn signals!
I would like to make some thing simular for customizing my car, van and possibly bicycle...Its all about learning new things and putting them to use. please let me know if theres anything you know or instrucables that will help me put something together. I will be looking at your bread board intsructables next ! Thanks so much!
meztek4 years ago
Great refresher! Very informative and easy to understand instructable. I am an amateur electronics hobbyist and this was just what I was looking for!
jamin814 years ago
Let's say that I have a power supply that is 5v at 0.7 amps but I want it to power and load that requires 5v at 20mA. I don't want a voltage drop but there is too much current. How do I calculate the resistor needed?
4 years ago
If you put a resistance in series with the load, then the voltage across the load will be less than 5V. What you can actually do is just connect the load directly to the 5V. When a power supply says it's rated for 5V and 0.7amps, what that means is it will put out 5v at any amperage up to 0.7amps. So your load will work fine. Power supplies put out a fixed voltage and current will be determined by the resistance of the load.
seibermaki5 years ago
Man, I totally forgot what resistors were for. I used to have an old Radio Shack electronics kit for kids in the 80's. It had all the resistors and whatnot already on the board. This instructable was totally easy for me to understand. Thankfully, it covered what I am interested in: making my own LED stuff. Now I just need to figure out how to automate the LEDs to blink or strobe. Thanks!
4 years ago
One way to do that would be to take a look at these: http://en.wikipedia.org/wiki/555_timer_IC  and/or find a related instructable.
5 years ago
thanks for brief, simple and constructable gets to the point :)
Michaeli4 years ago
pfiddle5 years ago
Well done - I know this stuff and it's great to see it set out simply and correctly. The illustrations are just about right.
Keep at it.
insmac5 years ago
Great job! Cool illustrations. Couple of minor points: The input resistance of volts meters is not infinite. Typically in the order of mega ohms, it can cause errors in some cases. Current splits proportionally in parallel circuits based on the resistance in each branch.
Karasjok5 years ago
Bravissimo!

Thank’s for this tutorial! Loved it, since I know nothing about electronics.
szechuan535 years ago
Great job, you should expand on it tho. Still great!
actingbiz15 years ago
Great guide! It was very informative in such a small package. Thanks!
Cew27 (author)  actingbiz15 years ago
thank you!
edfel015 years ago
This is an excellent clear instructable. Could u also explaine capacitors, transisors, diods, and other stuff like that thx. +5 rating
Cew27 (author) 5 years ago
sorry for the boxes, their meant to be ohms symbols, i have emailed admin to see about it, if it cant be fixed ill replace them with just the word ohms
5 years ago
if i use a resistor that is too much (say a 10ohm when i need ~3) what effect will that have?
Cew27 (author)  Detach505 years ago
in this case it is an led so it will not be very bright, or as bright as it can be.
Xellers5 years ago
Why isn't this featured? Write another instructable that talks about some other more complicated things too. IE. Capacitors, transformers, inductors, LC circuits, radio circuits, and the thing that most people don't understand: transistors.
Cew27 (author)  Xellers5 years ago
thanks, my next project (hopefully up this weekend!) will be how to build a cmoy amp. then i shall go onto transistors
PKTraceur5 years ago
Could you add what a transistor does? And how an antennae works? (I just dont know how a transistor works, or how I can applicate it to a circuit. For series, could I just connect it to the collector and emitter?{BCE}) -RoAr
5 years ago
http://www.rason.org/Projects/transwit/transwit.htm

before that I never got how to use transistors
5 years ago
? ? ? I thought they were amplifiers? And when will/if I use them for switches? -RoAr
5 years ago
most people actually uses transistors as switches, like: using microcontrollers to: turn on relays turn on a whole bunch of LEDs turn on motors turn on solenoids etc... they're still amplifiers, sure they have a hole bunch of semi-on values (for amplifiying a signal), but as a switch you can think of a mechanical switch as a potentiometer with 2 values. Verry low, and very high.
5 years ago
So, they can vary voltages, wheras a SPST switch has whatever voltage is in the circuit, and no voltage. A Transistor can have voltages ranging? -RoAr
5 years ago
yeah, a transistor can only handle a certain amount of voltage and current, like a switch. Also, NPN transistors should have their emitter grounded, so that their base will work off of normal voltages, like 5 volts. If you were to put the load between the emitter and ground (for a 12 volt circuit) it would take like 13-15 volts to turn on the base (with proper bias resistor)
uguy5 years ago
Step 1. and splits in a parallel circuit evenly. How so? If two parallel resistors are of different values?
Cew27 (author)  uguy5 years ago
thats across identical components
mowdish5 years ago
In the first sentence of step 3 you said, "in a series circuit components are connected..." I think you meant "in a parallel circuit..." Another nice introduction. Keep up the good work.
guyfrom7up5 years ago
Nice job, I've attempted to write electronic tutorials, but for some reason it was just a train crash near the end. Lol
Phil B5 years ago
These things are not the easiest to explain in a few short steps. Thanks for your Instructable. I hope you will also do more Instructables on other things, like capacitors and transistors, as well as how these things function in combination. I was always especially interested in radio circuits and how they work. Now the big thing seems to be digital circuits, especially for handling data and computing.
Cew27 (author)  Phil B5 years ago
thanks alot, remember to rate and suggest improvements