Author Topic: General use transistors  (Read 2258 times)

0 Members and 1 Guest are viewing this topic.

Offline shobo

  • Regular Contributor
  • *
  • Posts: 61
  • Country: ro
General use transistors
« on: December 21, 2017, 01:38:57 pm »
what are the most used and basic transistors that a beginner can buy and/or is recommended to start with?
 

Offline jonovid

  • Frequent Contributor
  • **
  • Posts: 831
  • Country: au
    • JONOVID
Re: General use transistors
« Reply #1 on: December 21, 2017, 01:56:24 pm »
This e-book contains 100 transistor circuits
http://www.talkingelectronics.com/te_interactive_index.html
Hobbyist with a basic knowledge of electronics
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #2 on: December 21, 2017, 02:22:04 pm »
2n3904 -> general purpose does everything NPN. I keep 10 on hand.

2n3906 -> general purpose does everything PNP. I keep 5 on hand.

MJE3055 -> power. I keep 2 on hand.

2n2222 -> slightly higher current general purpose NPN. I keep 5 on hand.

buy anything else if you need it. I rarely need anything else if I'm honest. Occasionally an RF PA or something a bit higher Vce and that's it.

Don't buy shitty Chinese transistor assortments. Not worth it. The above set is so ridiculously cheap it's not worth buying crap.
 
The following users thanked this post: ratio

Offline mariush

  • Super Contributor
  • ***
  • Posts: 3940
  • Country: ro
  • .
Re: General use transistors
« Reply #3 on: December 21, 2017, 02:26:59 pm »
Go to any electronic components store, select through hole parts and pick best price at a high quantity, or what's stocked in the highest amount ... that should be the most common jellybean transistors.

For example: 

cheapest per 1000pcs through hole transistors : link

biggest stocked transistors (you'll notice a lot of part names are same from the list above)  :  link

Also google  jellybean components site:eevblog.com to find a list of threads on this forum about components recommended for beginners.   
 

Offline madires

  • Super Contributor
  • ***
  • Posts: 5133
  • Country: de
  • A qualified hobbyist ;)
Re: General use transistors
« Reply #4 on: December 21, 2017, 02:41:02 pm »
Some jelly bean NPNs and PNPs, like BC548 & BC558. Darlington would be BC516 & BC517. For larger currents maybe BD135 & BD136, and TIP31 & TIP32. A few 2N3055 might come in handy too. Also get some heatsinks plus mounting stuff for the power transistors. I think that should be a nice starter package. Anything else will depend on your interest in specific topics later on.
 

Offline danadak

  • Super Contributor
  • ***
  • Posts: 1875
  • Country: us
  • Reactor Operator SSN-583, Retired EE
Re: General use transistors
« Reply #5 on: December 21, 2017, 04:54:56 pm »
A cheap way of getting a few variants (kit boxes down the page) -


https://www.banggood.com/search/transistors.html


Regards, Dana.
Love Cypress PSOC, ATTiny, Bit Slice, OpAmps, Oscilloscopes, and Analog Gurus like Pease, Miller, Widlar, Dobkin, obsessed with being an engineer
 

Offline wraper

  • Supporter
  • ****
  • Posts: 11360
  • Country: lv
Re: General use transistors
« Reply #6 on: December 21, 2017, 04:58:26 pm »
A few 2N3055 might come in handy too. Also get some heatsinks plus mounting stuff for the power transistors.on.
Unless you need to fix some old design stuff, they should be forgotten and left in the history FFS.
« Last Edit: December 21, 2017, 05:00:06 pm by wraper »
 
The following users thanked this post: kony

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #7 on: December 21, 2017, 05:03:12 pm »
Yep MJE3055 is nearly as good and is straight TO220. Or stop burning off the power and use a switching supply.
 

Online rhb

  • Super Contributor
  • ***
  • Posts: 2815
  • Country: us
Re: General use transistors
« Reply #8 on: December 21, 2017, 07:33:02 pm »
How much do you have to spend?  If you have plenty of cash, buying first line transistors in lots of 100 from Digkey, Newark, etc is quite sensible.  On the other hand, if cash is tight, I'd buy an assortment of transistors from China.  I stumbled across this:

https://www.ebay.com/itm/960pcs-24-Values-BC327-S9015-PNP-Silicon-Three-Pin-Transistor-Assortment-Set-SG/112675170770?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

At 1.7 cents US each, that looks like a pretty good deal.  I have quantity 100 of several types, but I'm going to buy a couple of assortments just to see what they are like.  I've got a Peak Technologies DCA75 tester which provides curve tracing.  So I'll be able to make good  comparisons to devices from Motorola and similar OEMs.

An important thing to remember about transistors is that they vary a lot, both individually and from lot to lot.  An important aspect of transistor circuit design is to take that into account.

If you're a beginner and cash is tight, get a $20 EBay LCR-transistor tester and assortments of NPN and PNP transistors, resistors and capacitors from eBay.  Measure several of each type with the tester and then build some basic amplifier circuits.  Feed them a PWM signal from an STM32F4 Discovery board or similar and examine the rise time and signal fidelity.

A staggering number of circuits have been designed using a 2N2222 or 2N3904/6 for very good reasons.  They are incredibly versatile.
 

Offline wraper

  • Supporter
  • ****
  • Posts: 11360
  • Country: lv
Re: General use transistors
« Reply #9 on: December 21, 2017, 07:40:34 pm »
https://www.ebay.com/itm/960pcs-24-Values-BC327-S9015-PNP-Silicon-Three-Pin-Transistor-Assortment-Set-SG/112675170770?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

At 1.7 cents US each, that looks like a pretty good deal.  I have quantity 100 of several types, but I'm going to buy a couple of assortments just to see what they are like.  I've got a Peak Technologies DCA75 tester which provides curve tracing.  So I'll be able to make good  comparisons to devices from Motorola and similar OEMs.
Don't expect anything resembling what should be inside them according to the model. Not only they can be crappy parts but parts with completely wrong specs like operating frequency or voltage.
 

Offline mrkev

  • Regular Contributor
  • *
  • Posts: 214
  • Country: cz
Re: General use transistors
« Reply #10 on: December 21, 2017, 07:59:04 pm »
If you are in USA, I guess that what bd139 wrote is the stuff you need.
If you are in europe, I would go by madires (BC's are more common here).
If you need some SMDs BC807 and BC817. I also have 2N700 , 2N7002 (SMD) or BSS138 (SMD) N-fets, BS84 (SMD) P-FET.
 

Offline Dbhrs

  • Newbie
  • Posts: 4
Re: General use transistors
« Reply #11 on: December 21, 2017, 09:34:23 pm »
This is just the kind of information I was looking for.


Sent from my iPhone using Tapatalk Pro
 

Offline Damianos

  • Regular Contributor
  • *
  • Posts: 206
  • Country: gr
Re: General use transistors
« Reply #12 on: December 21, 2017, 10:41:09 pm »
2n3904 -> general purpose does everything NPN. I keep 10 on hand.

2n3906 -> general purpose does everything PNP. I keep 5 on hand.

MJE3055 -> power. I keep 2 on hand.

2n2222 -> slightly higher current general purpose NPN. I keep 5 on hand.

buy anything else if you need it. I rarely need anything else if I'm honest. Occasionally an RF PA or something a bit higher Vce and that's it.

Don't buy shitty Chinese transistor assortments. Not worth it. The above set is so ridiculously cheap it's not worth buying crap.
You forgot the BD139 and BD140!
The 2N3904 and 2N3906 are around 5€ to 6€ per 100, from official distributor. So, happy burning!!!
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #13 on: December 21, 2017, 11:08:47 pm »
Doh you're right :palm: ... BD139 makes a good RF class C PA for sub 30MHz. BD139/140 pair make good audio amp transistors.

As for burning them, yep. If you even suspect you cocked up, just chuck the transistor in the bin. It's quite easy to not blow the ass out of a 2n3904 but ruin it so badly you will tear your hair out trying to work out why your circuit no longer works properly.
 

Online rhb

  • Super Contributor
  • ***
  • Posts: 2815
  • Country: us
Re: General use transistors
« Reply #14 on: December 21, 2017, 11:18:03 pm »

Don't expect anything resembling what should be inside them according to the model. Not only they can be crappy parts but parts with completely wrong specs like operating frequency or voltage.

One can reasonably expect that the parts with the same markings are similar.  More than that is  unknown.  I do not recommend the assortments for project construction stock.  But for a novice with limited funds, there is a lot of educational value in figuring out how to properly characterize and apply them.  For a long time I was hung up on "I need a 2Nxxxx"  when in fact I just needed  a transistor. 

Growing up, I was dissuaded from doing many things by advice from my father.  I'm sure he meant to be helpful, but he so complicated things that many projects were abandoned because it was beyond my abilities.  Graduate school taught me the value of failure.

A poor instrument is better than no instrument.  A stock of dubious parts is better than none.  When I was a kid, it was common to buy bags of unmarked transistors.  I still have some of those.  I never used them because I never found out how to test them and had nothing but a VOM.  Now I would breadboard an amplifier circuit and feed a pulse to them and look at the response if I had limited funds.  As I now have a curve tracer, I can do far better.

One of my goals in buying some assortments is to address the problems they pose to novices.  Whether  wise or not, people do buy these.  It seems to me measurements are more useful than innuendo.

For small signal  work, the 2222, 3904 and 3906 will cover almost everything except JFETS. That used to be the MPF102, of which I still have close to 100.  I'm not sure what a suitable equivalent is today.  I spent a good bit of time researching the subject without finding an answer.  I *highly* disapprove of publishing designs based on obsolete parts unless the relevant design parameters re explicitly stated. 

Old parts that have been in production for a long time are generally good choices. However, in manufacturing saving a few cents per hundred matters.  For a hobbyist  it is not an issue.  The 3rd ed of "The Art of Electronics"  is a good reference for parts choices as well as being an education in itself.

If you think you burned a transistor, put it in a "suspect parts" bin until you learn how to test them.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #15 on: December 21, 2017, 11:29:18 pm »
Fairchild J113 is modern sub for MPF102. Not a lot of people know that. They're a hell of a lot cheaper!

If you know your parts well and have a beady eye you can actually make a ton of cash selling certain transistors because people don't know how to sub. I've got a box of 2N4416's here ready to go. 1971 dated RCA.

China knocks out a lot of crap transistors. As a beginner you owe it to yourself to use quality parts to start with. Then when you know what you're doing you know when things go wrong. It's the difference between $1 and $3 really. Hardly anything.
 

Online rhb

  • Super Contributor
  • ***
  • Posts: 2815
  • Country: us
Re: General use transistors
« Reply #16 on: December 21, 2017, 11:49:51 pm »
I looked at the J113 and friends.  Probably close enough, though I seem to recall I had some questions relative to the MPF102.  Might not be anything but imagination on my part though.

So what's a good sub for the 4416?  That was on my list to buy until I saw the prices.,

This conversation suggests I should write a program to find subs.  Does anyone know of a source of machine readable specs?

I  completely agree that for a rank novice, a dozen 2222, 3904 and 3906 parts from a reputable parts house is far better than a Chinese assortment.  There's an intermediate ground in which you learn what characteristics matter and when.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #17 on: December 22, 2017, 12:07:55 am »
Problem with JFETs is the device spread is huge so a shitty 2N4416 is worse than a good J113. You can be quite flexible with substitutions. 2N3819 is pretty good allrounder as well and not crazy expensive (yet). Sometimes the transconductance is off so you have to change a resistor or two. Bar a few commercial designs, most of the circuits that require the FETs listed above only work with the device the author had so you have to frig stuff anyway.

alltransistors.com has a massive database which you can probably scrape easy enough.
 

Offline jaycee

  • Regular Contributor
  • *
  • Posts: 196
  • Country: gb
Re: General use transistors
« Reply #18 on: December 22, 2017, 12:11:21 am »
Depends where you come from. In the UK and some parts of Europe, small signal "jellybean" transistor is usually BC546/BC556. If you're American, it's usually 2N3904/2N3906 or MPSA06/MPSA56. If you're Japanese, it's probably 2SC945/2SA733. Apart from the different pinouts they're all plenty good for general use.

For a bit more power, BD139/BD140 are handy to keep. TIP31C/TIP32C are also useful. For even more power you cant go wrong with TIP2955/3055 (or the 2N types if youre old school and want TO-3 packages).

 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 14610
  • Country: gb
Re: General use transistors
« Reply #19 on: December 22, 2017, 12:13:27 am »
BC (pro-electron) ones are more expensive than 2N ones I find, even in the UK. Not sure why!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf