transistors

Wig

I'm making this circuit, without the RTS line.



And I'm using BC546 and BC556 from Maplin, I need to confirm that I definately have the pin outs correct, Maplin catalog said they were both the same (T092), but I was the one reading it and I don't know my !!!! from my elbow when it comes to this stuff.

I'm confused because Maplin had a diagram like this

But in the Maplin one it said the pins (on the T092) were BCE (flat side up), I think from what I have worked out, BCE (flat side up) would match the circuit diagram - because '1' is the collector right? and in the circuit diagram for both transistors '1' is in the middle.

But the T092 layout above is different and also this page shows the BC546 in a different layout CBE or 123

So why is there this difference in the layout of BC546 from diff sources, and how do I know for sure which one I have?

EDIT to add..
The face of my transistors says
C546B
W 60 (?)

C556B
W 54 (?)

Stompa

My memory is a bit rusty on this stuff, but I think you'll find that TO92 just refers to the shape/type of packaging and not the configuration of the leads:

http://en.wikipedia.org/wiki/TO92

You can't assume that the actual pin connections bear any resemblance to the way they're shown on the circuit diagram.

I would have thought the datasheets here:

http://www.onsemi.com/pub_link/Collateral/BC546-D.PDF

http://www.fairchildsemi.com/ds/BC/BC556.pdf

should show the correct pinouts.

dieselglider

A bit rusty myself, but have a look at this, and this, noting the 'B' configuration on the tables when you scroll down.

bookduck

You brought back some memories with this post. Stompa is correct

TO92 is the shape/dimensions/position of the transistor case and leads. It has nothing to do with the actual lead output configuration.

There are a good few (6?) different lead configurations. Look for lead outputs instead.

You can on most transistors use a multimeter to find the Base which give you a 50-50 chance But you'd be better off going with Stompas data sheets.

penrhyn

Whoops duplicate post.

penrhyn

In your circuit diagram the pin 1 is the base, pin 2 the emitter and pin 3 the collector.
The outward arrow tells you they are NPN devices.

Can't quite understand why you have referred to surface mount devices as these are all through hole packages.

espresso

Wig wrote: »

I'm making this circuit, without the RTS line.

What is it for?

superscaper

espresso wrote: »

What is it for?

Probably trying to access his car's on board diagnostics.

superscaper

penrhyn wrote: »

Can't quite understand why you have referred to surface mount devices as these are all through hole packages.

Same here. Was the OP intending to use SMT or not I wonder?

(By the way, re your duplicate post, you can delete your own posts in the edit)

Stompa

superscaper wrote: »

Same here. Was the OP intending to use SMT or not I wonder?

I wouldn't have thought so for a home-made project.

superscaper

Stompa wrote: »

I wouldn't have thought so for a home-made project.

Not usually but strange the OP should use the term unless they got it from somewhere.