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Topic: Some very basic electronic component questions (Read 1 time) previous topic - next topic


Hi everyone!

I'm an electronics newbie just getting started using an Arduino board an a couple of components.
I bought a kit on ebay that included a breadboard but also other small stuff that are required for building some devices. I know the use of most of them, but on the other hand I have no idea about the possible use / application of some others. So I would be very glad if someone just very briefly explained (or pointed me to a website where it's already discussed) what the following components are (or where they can be used). I got the names from the ebay description, maybe they are not 100% correct :):

- Mono capacitors
- Dynatron And Diode : BC547, BC557, 1N4007, 2N3904, 2N3906
- Optical Coupling : 4N35
- Darlington : TIP122, TIP127
- FET : IRF540
- Power Chip : L7805, LD1117 3.3V
- Chips?74HC595, ULN2803A

The kit itself is the following:

Sorry for asking such basic questions but everyone has to go through the learning phase I guess. :)

Thanks & best regards,


Some of those names are wrong, in the eBay description, or at least mis-translated.The 'dynatron' should be called 'transistor', and are the BC547, BC557, 2N3904, and 2N3906. The diode, IN4007, is correctly named. The 'power chips' and 'voltage regulators'. The 'mono' capacitors are 'monolithic ceramic', which simply describes the material that the capacitor is made from, i.e. a single lump of ceramic. The 'chip' 74HC595 is a very useful shift register, and the ULN2802A is a handy eight-way relay, motor or solenoid driver.



I've walked your path a few weeks ago (different kit, similar parts). You'll quickly discover that:

- you won't have the parts your REALLY need to do what you want to
- you'll have lots of / some parts that you'll never need
- google and datasheets are your friends.

I just went thru all the examples in the arduino learning centre and then quickly started working on a personal project - that's when you start applying your skills and sourcing individual parts that you really need. I'm a photographer so my first projects revolve of course around photography.

good luck!



Sorry for asking such basic questions...

Not a problem!

In random order...

Widely used capacitors come in two forms: Electrolytic (little cylinders) and not. They both do the same thing in circuits, but the electrolytics can store more charge, handle higher voltages. The electrolytics are POLARIZED, i.e. it matters "which way around" you connect them. A leg will be marked + or -, if marked +, connect that leg to the higher voltage side of the gap the capacitor is going across. It is hard to use the wrong type of capacitor... find one of the right capacitance, and voltage rating, and use it. (Voltage rating: If you have a 5v circuit, you need a capacitor rated for 5v or more... and it is wise to give yourself a safety margin. 16 or 25 volt capacitors aren't much bigger or more expensive than 5 v capacitors... if you can even buy something with such a rating.

Diode, e.g. 1N4007: A "one way gate" for electricity. It will only let the electricity flow one way. It may be in the kit for being The Diode, as in...


Optocoupler, aka optoisolator: That 4N35 has a datasheet at...


... and you can learn about them in general from...


Darlington, FET : These are types of transistor.

L7805 is a voltage regulator. You give it 8-14 olts, approx, and the voltage can wobble, and it gives back a nice clean "REGULATED" 5v. You need some bits and pieces, mostly capacitors, in association with the 7805

The LD1117 is another voltage regulator, this time giving 3.3v. See http://www.datasheetcatalog.org/datasheets/700/392975_DS.pdf

Enjoy.... !

You need some switches (momentary and/ or toggle), LEDs and resistors, if you don't have them. Be sure to include a resistor when connecting an LED....



Many many thanks for the quick and detailed replies, guys!

Also thanks about the insights (that you probably won't have the parts that you actually need). :)

Thanks again!


Some suggestions for further components:
I usually have a variety of potentiometers at hand, because you'll never have the right resistors at hand  :smiley-mr-green:
For simple experiments, learn how to combine capacitors and resistors in series and paralel. This will keep you playing while you get the components.
Here is an example:

A regulable voltage regulator, like the LM317 is also nice to have when you need to play with different voltages.
My 2 cents.



Oooh, that is such a great site. I looked around at his tech info. Funny and useful!


Gotta bookmark that for when I get around to my tube amp project.
... it is poor civic hygiene to install technologies that could someday
facilitate a police state. -- Bruce Schneier

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