Useful components/parts for students/hobbyist

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Hi all,

I've really been having a lot of fun learning and playing with electronics and my atmega8/16s. While I feel good enough to call myself a newbie now I'm curious what components do you guys use most often?

I'm getting some atmega168 cause I want to make 3.3V circuits as well as some other components. I would like to get as many useful general/cheap parts if possible.

Last time I got 100 .1uF decoupling caps, and 100uF electrolytic caps both which I plan on using on many other projects and we great investments for large (for me) quantities.

I've learned when its ok to use these general sizes and when I need to go get a specific cap but that is not the case for coils/inductors. What are general inductor sizes you would recommend? What about diodes? Are these parts all to specific?

I know in industry you find the part that meets your minimum requirements because its usually the cheapest in large lots. In my case I don't mind paying bit more for more general parts in small lots.

I'm sure there are other newbies here who wouldn't mind knowing what components are good to have once we are feeling comfortable with electronics?

Could I also get some comments on this voltage regulator circuit?
Must the caps C1 & C3 be tantalum, or can the be electrolytic?
Could I replace C3 with a 100uF cap?
Could I replace Cc with a .1uF cap?
Like I said I don't know coils that well but can any other value be used with L1? (any comments on this would be appreciated)

Attachment(s): 

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emmannuel wrote:
Could I also get some comments on this voltage regulator circuit?
Must the caps C1 & C3 be tantalum, or can the be electrolytic?
Could I replace C3 with a 100uF cap?
Could I replace Cc with a .1uF cap?
Like I said I don't know coils that well but can any other value be used with L1? (any comments on this would be appreciated)
I can't answer your specific questions. In general, DC-DC convertors are great because they have high efficiency, but their stability depends upon having capacitors and inductors with specific characteristics (such as the ESR of the capacitor and inductor). Have you read the convertor's data sheet? The data sheet should specify what characteristics are important for the additional parts and their valid range.

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Thanks for your input Kevin.

From my understand of the datasheet it doesn't have a problem with electrolytic caps but like you mentioned they are more worried about proper ESR.

I couldn't see ESR listed for ceramic caps... why?

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emmannuel wrote:
I couldn't see ESR listed for ceramic caps... why?
While ceramic capacitors have smaller capacitance than ESR and tantalum, their ESR is quite low. For some applications, the ESR of ceramic caps is too low and one would prefer an electrolytic with high ESR.

Here's some links to more info;

http://www.murata.com/emc/knowho...
http://powerelectronics.com/mag/...

Google will find other information sources for you.

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emmannuel wrote:
I'm curious what components do you guys use most often?
Resistors :-)
Quote:
I would like to get as many useful general/cheap parts if possible.

You apparently want to build some stock of common parts. Unfortunately what is "common" varies greatly with the area you want to work in. It is also often a matter of opinion. E.g. there are better parts than 7805 voltage regulators. But 7805's are trusted and tried. So, do you stock them or stock something better instead? Or do you stock both 7805s and something better?

For hobby projects I try to follow a simple guideline. To only buy what I need for a particular project in the minimum possible quantity. If I break something I have to order again (it goes on a list of parts to order, and when there is enough on the list I order). It helps to have a few projects going on in parallel. If you are stuck with one you move to the next.

It's different for pro work, where time is money. There I find it absolutely necessary to have enough stuff at hand. And from time to time to clean up.

I can tell you what does not work. Sets. These bags full of parts are almost always just junk. Sets "never" contain the values you need, in the size you need. In fact, the values in sets are often the most uncommon one can imagine. The characteristics of the components are unknown. You have no idea what happened to the parts previously. Are they rejects? Have they been stored correctly? Did they fall of a truck? For chips, are they fakes? With sets you often pay for the privilege to dispose someone's electronic junk. eBay is often the same.

There are exceptions. E.g. some component manufacturers provide sets of their parts for evaluation. But that is a totally different story. Some vendors provide sets of e.g. the E24 series of new 1/4W resistors from let's say 10 Ω to 10 MΩ, 20 resistors per value. You will never use all values, and some values will be used up quickly, but such a set of new resistors might be worth to consider.

But my general recommendation is: Just buy what you need for your projects. Over time you will end up with a collection of parts, e.g. from abandoned projects or when you recycle parts from old projects or other old electronics (PC motherboards, etc.). Over time you will also learn what common parts you use often and then you can stock them.

Quote:
What are general inductor sizes you would recommend?
None. Properties of inductors vary greatly and you should get the ones that match your particular project. If you, however, find out over time, that you often use the same inductor you could consider stocking them.
Quote:
What about diodes?
1N4001 or 1N4007 (higher amp rating), 1N4148 (or 1N914), and 1N5819 (schottky). All these are rather old dogs with good enough properties for common tasks and they are cheap. You find them in many old circuits and they are popular among amateurs.

Quote:
Could I also get some comments on this voltage regulator circuit?
Must the caps C1 & C3 be tantalum, or can the be electrolytic?
Carefully check the datasheet. When the manufacturer says it must be tantalum, use tantalum. When the manufacturer says "capacitor must have property X, and tantalum capacitor Y has it", then carefully check if your electrolytic capacitor has property X, too.
Quote:
Like I said I don't know coils that well but can any other value be used with L1?
You should use an inductor with the right value. The manufacturer's datasheet should provide the formula to calculate the inductor's inductance. The magnetic material needs to be selected so it won't be saturated and works well at the converter's switching frequency. Unfortunately, datasheets often just point to a particular magnetic core, so you either have to try to get that core, or the datasheet for it to figure out the properties. Or you make a reasonable selection, or you try your luck with something you happen to find in your parts bin.

Stealing Proteus doesn't make you an engineer.

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Thanks a lot of your comments/experience Arnold and kmr they are appreciated.

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On the other hand...

I'll keep a good stock of the components that I use most.

Thru-hole
Capacitors:
22pF 50 volt ceramic
0.01uF 50 volt ceramic
0.1uF, 50 volt ceramic
1uF, 16 & 35 volt electrolytic
47uF 16 & 35 volt electrolytic
10uF, 35 & 50 volt electrolytic
100uF, 35 & 50 volt electrolytic

1/4 Watt Resistors:
100 Ohm 1% metal film
180 Ohm 1% metal film
220 Ohm 1% metal film
330 Ohm 1% metal film
470 Ohm 1% metal film
680 Ohm 1% metal film
810 Ohm 1% metal film
910 Ohm 1% metal film
1.0K Ohm 1% metal film
1.5K Ohm 1% metal film
1.8K Ohm 1% metal film
2.2K Ohm 1% metal film
3.3K Ohm 1% metal film
3.9K Ohm 1% metal film
4.7K Ohm 1% metal film
5.1K Ohm 1% metal film
6.8K Ohm 1% metal film
7.5K Ohm 1% metal film
8.1K Ohm 1% metal film
9.1K Ohm 1% metal film
10.0K Ohm 1% metal film
33.0K Ohm 1% metal film
47.0K Ohm 1% metal film
68.0K Ohm 1% metal film
100K Ohm 1% metal film
1.0M Ohm 1% metal film

Transistors:
2N3904 NPN.
2N3906 PNP.

IC's:
Basic logic gates, both TTL & CMOS.

Atmel AVR micro-controllers:
Mega2313 SOIC & DIP.
Mega88 TQFP & DIP.
Mega168 TQFP & DIP.
Mega32 TQFP & DIP.
Mega644 TQFP & DIP.

Other stuff:
FT232BM TQFP
FT232R SOIC.

Tactile momentary switches.
LED's.
1N4148 switching diodes.
1N4007 GP diodes.
Terminal blocks.
A good assortment of 1 by 36 and 2x5 headers 0.1" spacing.
Several 1x16, 4x16, 4x20 HD44780 based LCDs

ATAVRISP-MK2
ATAVRJTAG-MK2
STK500
STK600

I also keep several small "Home Brew " controllers that I've built as secondary devices for things like sending serial data streams and test patterns to the project under development - as well as providing an stand-alone programmable oscillator for when I miss-set the AVR clock FUSE bits.

Over the past several years I've migrated to SMD construction of my PCBs. I'm taking the same approach with SMD components, as well. As I rarely use thru-hole components anymore, I may decide to sell off my thru-hole components - though many of the more exotic ICs are somewhat obsolete now.

I could go on, as this is only a very small listing of parts I keep on hand.

Personally, I find it quite frustrating to be heavy into a project, only to find out that I'm short a part and will need to wait on a shipment to arrive before I can continue.

I usually try to spend about $100.00 each month on parts, simply to maintain the parts inventory that I have, as well as purchase new devices that I will one day want to experiment with.

My opinion is that you can never have enough parts or equipment available on the work bench.

But your storage space and hobby budget will dictate your particular requirements.

Have fun learning, building and spending money on the hobby

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Emmannuel,

Quite a nice list provided by Carl.

You may want to add a few bi/tri-color LEDs to play with, and perhaps a Dallas Semiconductor digital temperature or clock chip. These are good for tinkering with, learning to interface with, both using the standard interfaces, and learning to bit-bang them for experience.

Carl included the FTxxx chips for serial to USB communications. He probably has a couple of Max232 chips lying about, also, unless he has gone totally USB. They are useful for interfacing the uC USART to a PC's serial comm port, if your PC still has one.

Add a few crystals to the list, 14.7456 MHz will give you 0 % baud rate error.

Add a few op amps to the list, LM-324 is a cheap, quad, general purpose op amp. Better op amps certainly exist. Your assortment will grow as you work on projects.

If you have a serial port on your computer you will need some 9-pin connectors for it, too.

Some small bolts, washers, & nuts for mounting things, and rubber grommets for routing wires through holes are also helpful.

Add a Piezo-electric beeper or two, so you can make things beep.

You will probably want a few assorted battery holders, too. And a few wall warts for powering projects.

You did not mention what you have available for benchtop test equipment. A power supply is nice and saves on batteries. A decent DMM, (Volt-Ohm meter, etc.), is needed. Some include low end frequency meters which is nice, assuming you can't afford a good stand alone meter at the time. Eventually a scope is extremely helpful.

Don't forget a decent soldering iron. I also have a headband magnifier, and a jeweler's loupe, both useful to see small stuff, (solder joints, print, color codes, etc.).

A 2N2222 has a little higher current capacity than the 2N3904, and the TIP-102 is an NPN Darlington that can carry 8 Amps, and has a gain of 1000 (minimum). I don't have many Fets, but probably good to have some on hand.

The list goes on and on...

JC

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And then there hare the "hard to get" components..

I started collecting inductors,coils,crystals,....
from old equipment years ago and it pays off !

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DocJC wrote:
Emmannuel,

Quite a nice list provided by Carl.

I would have added a lot more to the list, but duty called and I had to take care of some "Honey-Dew " type responsibilities.

DocJC wrote:
Carl included the FTxxx chips for serial to USB communications. He probably has a couple of Max232 chips lying about, also, unless he has gone totally USB. They are useful for interfacing the uC USART to a PC's serial comm port, if your PC still has one.
Yes, I have about 10 to 15 MAX232CPE RS232 level converters in DIP, and about 10 Sipex SP232 level converters in SOIC. I don't think I'll be moving exclusively to USB until USB becomes a easy to implement controller to controller communications as RS232 currently is.

DocJC wrote:
You did not mention what you have available for benchtop test equipment.

I can't stress enough, making quality test equipment purchases. But that will largely depend on your budget.

DocJC wrote:
Don't forget a decent soldering iron. I also have a headband magnifier.

If you can get extravagant on any one tool purchase, a good soldering iron is a must - especially if working with fine-pitch SMD components. I've used the Weller TPCT (or something close to that) model soldering station for years. It's about 30 watts, fixed temperature.

Recently I purchased a Hakko FX950 soldering station and made the investment in about 10 different heating elements with different shaped tips. The soldering ability with a fine tipped soldering iron is like the difference between night & day. If you have to scrimp on the other test equipment, fine! But if you can't solder those SMD components to the PCB, you've gained nothing. And be advised, all of the really interesting components have gone to SMD packaging.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Thanks a lot of the advice. After taking a microcontroller class and learning the atmega16 I felt confident enough that I got an stk500 that xmas. I've also cashed in all my coins (for an amazon card), and with a friends amazon rebate picked up the $150 Weller soldering iron for $20 out of my pocket. I got a decent quality DMM too :D

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In first place, greetings to group!

I must say that all of above posts are more than just posts! That is experience by doing.

One of advices, don’t be in doubt to throw some “useful” stuff from your room or lab!

Trash will bulk up for sure, so when u get some old/new stuff, it is best to take IC’s resistors, caps, all general things! But if you see that is pain and time consuming job to desolder, THROW it away, some components are not so expensive! Separate things you have or its likely that you will order some stuff that you already own.
Shelf’s for parts are “cheap” so separate parts.
Very good thing from beginning, which is time consuming, is to note, what you have on “stock” (Notes on PC, not papers, papers get lost) and of course where you can find it (box, shelf, device…)

Always try to have clean desk, so when you finish some quick soldering, clean desk.

Better spend more money for quality (supply, measuring devices), then buy something just to have it… That is including development boards, I didn’t buy development boards, I did have no chance to buy STKxxx or some fancy things when I started (Now I can buy it/them, but who will wait for something when I can build it from piles of junk in minutes ;) ).
Excuse me but it is shit when you want something to work on/with in development
and you are not certain is it working, you can spend time on doing new things, but NO you will be blocked by searching for stupid bugs in your home made development board(downloaded all kinds of schemes, tested not tested, supported not supported)
It is always better to have less doubt in equipment you are using, even when debugging simple stuff.

And ohhhh dirt is your enemy, not just by making your hands dirty, inhaling dust from electronics is not good, ventilate, use alcohol to clean, wash hands, have “clean” equipment.
When you are on expedition on market place, stay sharp, things that you may use, is OK, but double may, is big NO NO.

Matthew