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Really dumb dumb question (Now i've soldered them in place)

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Gabrielle

New Member
BUT lol... do resistors have a specific way to go, or will they work either way ? gawd.. I hope you say, either way hehehe

Sorry about the dumb questions but i am a total novice (well experience from 20yrs ago, plus im a woman and im trying).
 

Kingpin094

New Member
Fortunately you are in the green.
Resistors don't care which way they go in.

BTW what are you building?
 

Gabrielle

New Member
a parallel interface for my PC, so i can turn stuff on and off from the computer via a simple program. :)
 

olly_k

Member
Good luck with the project, and just remember there is no such thing as a daft question.... You know the rest lol! I always say get the question over-and done with cos no matter how trivial it may seem now, it may cause a lot of headaches further down the line - then you would feel dumb!
 

stevez

Active Member
I am sure that someone will try to prove me wrong but I'd argue that there is no such thing as a dumb question. With many electrical components direction does matter. Sometimes the so called "dumb" questions aren't so dumb and help to reveal some common misunderstandings or beget some really good discussions. I am also willing to admit that the fact that some brave soul had the guts to ask a "dumb" question allowed me to learn a little something - and spared me having to swallow my pride and ask.
 

Gabrielle

New Member
thank you steve :) I do have another 2 questions... now.. starting to panic, as i do the test, and not getting the results that i expected.

Okies they are,
BC547's have 3 pins, i take it the middle pin is the in pin (2) and pin 1 & 3 are the out pins ? also i have a 2N3055 Relay with 2 pins.. pretty straight forward looking, but just checking, left pin is in, right pin is the output ??? not sure that makes sense... :(
 

olly_k

Member
The components you describe are both transistors. The BC547 is a Low power Low frequency NPN-bipolar transistor in a standard To92 case. Look at the component from below, with the notch facing to your left. The first lead at the top is the Base. Middle lead the Collector and bottom lead is the Emitter. This Transistor has a max current rating of 100mA and a gain (i.e. current flowing into base, x gain = current flowing into collector) of between 420 - 800.
The 2n3055 is NOT a relay but also an NPN transistor. It is designed for Power applications (requiring high currents) and has a maximum current handleing of 15A. The case style is a To3. The reason for all the metal is so that the transistor can more efficiently dissipate heat when handling higher loads. It is really designed to be attached to a heatsink. The two pins veiwed from below, and slightly offset to the left are - upper emitter and lower base. As for the collector? well the whole case is the collector! This is the equivelent 'third' pin if you like and would have to be connected to the circuit through a 'bonding' wire or similar. The gain of this device is relatively low, about 50 times.
If you want to learn more about transistors there are a few posts in these forum that I think will help :)
This is a good start...
http://www.electro-tech-online.com/threads/dc-motors.35/
 

Roff

Well-Known Member
olly_k said:
<snip>The first lead at the top is the Base. Middle lead the Collector and bottom lead is the Emitter.<snip>
The datasheet I looked at says 1=emitter, 2=base, 3=collector, top to bottom when viewed as you said. Do you have a different datasheet?
 

xjackal

New Member
well.i have worked with bc 547b and im sure that its top-to-bottom as u say the order is 1-collector 2-base 3-emitter
 

Sebi

Active Member
The small-signal transistors have old standard pinout, as picture show.
HF or driver transistors pinout order often same as TO139 package.
 

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olly_k

Member
The datasheet I looked at says 1=emitter, 2=base, 3=collector, top to bottom when viewed as you said. Do you have a different datasheet?
I think it must be a mistake in my catalogue - it says T092 but I am wandering if not a to92a. When I can be bothered (the wheather and work have wiped me out last couple days! lol) I will get a 547 out from the garage and stick it on my atlas and see what that tells me!
Thanks for pointing it out!
 
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