Very extremely simple basic clueless Question about Transistors

whiteoxe

I wanted to order some LED's because I found I had absolutely none and they are way helpful to signal my programming is OK..., and a few other bits so that the order would at least equal the postage cost and I can play around with my breadboards and re learn things I haven't done for years...just a bit of fun!!!

I wanted to get a few cheap transistors just to play with and try and remember how they work, npn and pnp. ( i remember one is more popular than the other) but the list of transistors to tick was very very long and the info beside them was similar and the price range was 16 cents to $1.29 (futurelec australia) http://www.futurlec.com.au/Components.jsp They deliver fast and postage is always minimal.

There are basically General Purpose Transistors, Switching, Power transistors.I used them long ago to turn on a led or a relay, the most voltage I used was 6 volt i *think* and the relays i used were in clear casing so i could see them work, but i dont remember what they were i just ordered a couple randomly and got them to work . So if I just want to play with turning leds on and relays can you give me a hint, will General purpose be all i need with both NPN and PNP ?

BTW. Are not Power Transistor Mosfets ?

I would also like to get a relay or two but not the ones in clear casing as they are much more expensive. Can you also suggest the type of inexpensive relay i might use to turn on a 6 volt motor ?

RDL2004

Get some 2N3904/3906. There's a BC equivalent but I can never remember the number. Power transistors can be any kind. 2N3055 is a very common BJT power transistor. These days, for switching use MOSFETS are more commonly used because they can be made to have a very low "on" resistance. For higher power use the bipolar TIP41/42 are okay.

whiteoxe

RDL2004 wrote: »

Get some 2N3904/3906.

Thats great , they cost 6 cents , the power transistor is $1.00, the postage for a bunch of parts is likely to be about $4.00 so ill have to think of a few more things

RDL2004

Get some resistors and capacitors, and plenty of LEDs

http://forums.parallax.com/showthread.php/154266-Parts-every-hobbyist-should-have

whiteoxe

OK thanks very much , I have enough now to justify the $4 postage. Resistors are about the only things I already had. Those big blue LEDS are fun

LoopyByteloose

Power transistors can run extremely hot and waste a lot of power in a battery context, so the MOSfet has pretty much taken over power switching. You can switch power directly with a TIP120 or TIP125 (Darlington pairs), but you also have about a 2 volt drop involved in most cases... so a 12 power supply might deliver only 10 volts to a motor.

The small devices 2n3904/2n3906 are handy and don't waste enough power to bother with shifting over to MOSfets. I like the 2N2222/2n2907 as well.

There are lots of other transistors, but these are the only ones that you will need for most micro-controller stuff.

The 2N3055 is a real sizzler that once was a work horse of controlling synchronization of the the high voltage in televisions. But to use it properly, you really should have a heat sink that is about 6" x 6" and 1" tall... not exactly small. Adding a fan might be wise too.

whiteoxe

Thanks Loopy.

Weird thing happened, my pc was acting hopelessly slow. ,i got a phone call after a couple of hours from some indian sounding accent offering their concern and a way to fix it. i said "excuse me did you say u were from my exetel my sevice provider", no he told me it was microsoft calling, spent a good half an hour with me telling me commands to type to clean system and he could see my screen. Then to finish off he took control of my machine while i watched. there was a trojan. So after it all my PC was blazing fast again and all fixed.

he offered me different priced sevice packages, i declined and the call ended. After a while i realized that microsoft has never done that out of the blue and ive never heard of anyone else having such a spontaneous call and help and taking over their computer.

So i reformatted the drives , put win7 and liux back on and changed all my passwords while laughing at myself for being taken in like that.nothing close to that has ever happened to me before.

Heater.

Wow, whiteox, you certainly fell for that one. Seems the guy owned your machine before calling you. Very sneaky. I have never heard of that particular scam before so I might have fallen for it as well. Except there is never MS software on any of my machines.

Still. It had a positive outcome. The scammer got nothing for his effort and you became aware of the holes in your machine. Mind you I'm not sure putting the same buggy OS back on there prevents that guy or someone else getting in a again.

whiteoxe

Yes heater... ive had phone call ,email and skype scammers of every kind and ive never come close to getting fooled, if bored ive played with them. This happened while my anti-virus program was off for 24 hours, so it came quickly..dont ask why anti virus was off ill have to type too much but yeah, the fellow was quite professional and convincing. it will get people no doubt at all. and yes i am trying to boott linux more and more so it becomes as easy and useful to me as anything else and i can feel more secure !!!!!
















9

Ttailspin

Oh me, oh my... You have not heard of the "Microsoft Tech Support Scam"??, it has been around for awhile, and seems to be making a come back as of late.
It's off to ScamWarners.com for the both of you...



The funny thing about transistors, is they don't seem to handle short circuits very well, not very well at all...
http://forums.parallax.com/attachment.php?attachmentid=92496&d=1336959728


-Tommy

LoopyByteloose

Here you go...

http://www.microsoft.com/security/online-privacy/avoid-phone-scams.aspx

You were right to reload everything after that. But I just stay away from Windows altogether. Nobody would every call to say they are the Linux Tech Support.

whiteoxe

I know during that time the anti virus was off i foolishly went to a torrent site and downloaded movies . you might say i deserved it what i was doing probably wrong and the universe was just getting even. so my pc is now all better. after a lot of work. but this laptop does not seem to have a virus, checks come back clean however both web browsers get way too many ads and pop ups and extra windows opening even when i click on a thread to reply in this forum. i am not sure whats going on but its really annoying.

RDL2004

If you have pop ups and windows opening just from clicking on links here at parallax.com, then you still have serious problems. I'd reinstall everything and use anything but internet explorer. I recommend Firefox with the NoScript add-on, and down load a good hosts file.

whiteoxe

RDL2004 wrote: »

If you have pop ups and windows opening just from clicking on links here at parallax.com, then you still have serious problems. I'd reinstall everything and use anything but internet explorer. I recommend Firefox with the NoScript add-on, and down load a good hosts file.

yes your right but this is my laptop not the destop with the microsoft scam.

And how did he het my phone number and know my internet privider and and have control of my pc before he even rang? Anyway Ive got kaspersky and microsoft essentials on the desktop and i wount be downloading from torrent sites again.(uning windows)

ps. Firefox is the best, second ....not sure.

Iwill fix the laptop with a reinstall but its a dell fromebay, Its a harder thing to reinstall because you have to go to the dell site and click on your laptop model and then click all the drivers you need and then it will be fine. Its just a bit more work,

frank freedman

fry's elex carries a pack made by velleman (also caps resistors etc) for the hobby use. many types including the BC versions you mentioned.

RDL2004 wrote: »

Get some 2N3904/3906. There's a BC equivalent but I can never remember the number. Power transistors can be any kind. 2N3055 is a very common BJT power transistor. These days, for switching use MOSFETS are more commonly used because they can be made to have a very low "on" resistance. For higher power use the bipolar TIP41/42 are okay.

frank freedman

How lucky you are, our outside physicist had her PC encrypted by ransom-ware still not able to decrypt her files. years of reports and system test. programs locked forever...... unless she pays up. then, who knows.......

whiteoxe wrote: »

Thanks Loopy.

Weird thing happened, my pc was acting hopelessly slow. ,i got a phone call after a couple of hours from some indian sounding accent offering their concern and a way to fix it. i said "excuse me did you say u were from my exetel my sevice provider", no he told me it was microsoft calling, spent a good half an hour with me telling me commands to type to clean system and he could see my screen. Then to finish off he took control of my machine while i watched. there was a trojan. So after it all my PC was blazing fast again and all fixed.

he offered me different priced sevice packages, i declined and the call ended. After a while i realized that microsoft has never done that out of the blue and ive never heard of anyone else having such a spontaneous call and help and taking over their computer.

So i reformatted the drives , put win7 and liux back on and changed all my passwords while laughing at myself for being taken in like that.nothing close to that has ever happened to me before.

whiteoxe

Yeah, lets all change to Linux