Whilst I'm very pleased

There are 3 pinouts for TO-92: EBC, CBE, and BCE. 2N and BC are reversed from each other, 2SC put the collector in the middle. But watch out for reversed pinout devices. I have a bag of some BC transistor that was marked reverse pinout.

That 2N2222A in TO-92 always gives me heartburn. 2N2222A was always in a TO-18 package. What were they thinking?

From Texas Instruments 1973 Transistor and Diode Databook:
View attachment 286214

Thanks Dennis - there is a huge amount of confusion out there - for example these two sites list the pinouts as per my working circuit:
https://components101.com/transistors/2n2222a-pinout-equivalent-datasheet
https://microcontrollerslab.com/2n2222-npn-transistor-pinout-examples-applications-datasheet/
yet this one (and I'm sure others) lists the opposite:
https://www.electroduino.com/2n2222a-transistor/

Unfortunately onsemi only provide a datasheet for the P2N2222A...

I feel slightly less guilty putting you all through this - I blamed the brain fog but the two images I have are clearly the same part numbers with different pinouts! I think I should just order some 2N3904's and be done with it!

 

Thanks Dennis - there is a huge amount of confusion out there - for example these two sites list the pinouts as per my working circuit:

I'd trust manufacturer datasheets over any of the sites you listed.

Some/many hobbyists are too inattentive to details and often omit important information. I recently wasted my time trying to teach someone that pfet is ambigous and that FET is an acronym that should be capitalized. He eventually got around to "saying" "p channel mosfet" which should be written as P channel MOSFET.

 

I'd trust manufacturer datasheets over any of the sites you listed.

Some/many hobbyists are too inattentive to details and often omit important information. I recently wasted my time trying to teach someone that pfet is ambigous and that FET is an acronym that should be capitalized. He eventually got around to "saying" "p channel mosfet" which should be written as P channel MOSFET.

I did try but there is no 'official' datasheet for the 2N2222A (at least not one I could find), only for the P2N2222A at On Semi. The most official one I could find was at MIT here: https://web.mit.edu/6.101/www/reference/2N2222A.pdf but that was for the 'old style' packaging so no use for identifying pinouts.

 

The most official one I could find was at MIT here: https://web.mit.edu/6.101/www/reference/2N2222A.pdf but that was for the 'old style' packaging so no use for identifying pinouts.

The thing about those metal cans is that the emitter was always closest to the tab for single transistors.

This is from TI's 1973 databook:


You shouldn't have to worry about different manufacturers having different pinouts for the same part number. Any manufacturer claiming they have a 2N2222A in TO-92 is wrong. It's supposed to be in TO-18 as specified by JEDEC.

They can have a PN2222A in TO-92, or the ghastly numbered P2N2222A, but not 2N2222A.

 

The thing about those metal cans is that the emitter was always closest to the tab for single transistors.

This is from TI's 1973 databook:
View attachment 286223

You shouldn't have to worry about different manufacturers having different pinouts for the same part number. Any manufacturer claiming they have a 2N2222A in TO-92 is wrong. It's supposed to be in TO-18 as specified by JEDEC.

They can have a PN2222A in TO-92, or the ghastly numbered P2N2222A, but not 2N2222A.

Well it definitely says it's a 2N2222A in a TO-92 package!

I think I'll avoid all *2222* components in the future!

 

Well it definitely says it's a 2N2222A in a TO-92 package!

I think I'll avoid all *2222* components in the future!

I don't think it's really a 2N2222A. I suspect a counterfeit part. The leads look funny and the face of the package doesn't look like a molded part.

There are a lot of counterfeit parts around thanks to China.

 

Here are some pictures of transistors in TO-92. The top 3 are from stock I acquired in the late 70's. The bottom 3 are from eBay before counterfeiting became such a problem. Markings on two of the newer transistors is difficult to read because the part numbers are engraved. The thumbnail was taken at an angle so the part numbers can be read.

On counterfeit Motorola parts, they usually don't use the stylized 'M'. Manufacturers are particularly picky about how their logos look because that's their brand.

 

Here are some pictures of transistors in TO-92. The top 3 are from stock I acquired in the late 70's. The bottom 3 are from eBay before counterfeiting became such a problem. Markings on two of the newer transistors is difficult to read because the part numbers are engraved. The thumbnail was taken at an angle so the part numbers can be read.

On counterfeit Motorola parts, they usually don't use the stylized 'M'. Manufacturers are particularly picky about how their logos look because that's their brand.
View attachment 286239
View attachment 286240

I like the idea of having 'EBC' on the packaging. Seems eminently sensible...

 

I like the idea of having 'EBC' on the packaging. Seems eminently sensible...

I'm not sure what the motivation was, but I like it too. I have no idea what the house marked transistor in the middle of the bottom row is, but the lead markings are helpful because I'm also using BC547 (have a box of 2 or 3 thousand) in discrete gate circuits because the beta for saturation mode is 20.

The parts from the 70's with the embossed lead identification would also be hard to counterfeit. When they counterfeit parts, they sort them by package, sand/sandblast the original markings (or apply a "blacktop"), then relabel. On devices with leads, they sometimes have to repair them and many of the repairs are so bad that they're easy to detect.

When leads on transistors are shiny, I suspect counterfeiting.

 

The BC547 saturates with less base current because the 2N3904 saturates better using more base current.
The BC547 will also saturate better using more base current.

 

Whilst I'm very pleased


Thanks Dennis - there is a huge amount of confusion out there - for example these two sites list the pinouts as per my working circuit:
https://components101.com/transistors/2n2222a-pinout-equivalent-datasheet
https://microcontrollerslab.com/2n2222-npn-transistor-pinout-examples-applications-datasheet/
yet this one (and I'm sure others) lists the opposite:
https://www.electroduino.com/2n2222a-transistor/

Unfortunately onsemi only provide a datasheet for the P2N2222A...

I feel slightly less guilty putting you all through this - I blamed the brain fog but the two images I have are clearly the same part numbers with different pinouts! I think I should just order some 2N3904's and be done with it!

"..yet this one...lists.." And if you click on 'see Datasheet' it is back to EBC.

 

"..yet this one...lists.." And if you click on 'see Datasheet' it is back to EBC.

And the 'Download 2N2222A Transistor Datasheet' actually links to a P2N2222A... It's madness, I tell ye!

 

And the 'Download 2N2222A Transistor Datasheet' actually links to a P2N2222A... It's madness, I tell ye!

Datasheets from onsemi:

 

Why does anybody use a variant of an ancient 2N2222?
My first transistors were AC128 then BC107 then BC547. When I saw that they are European, I tried and used 2N3904 American transistors ever since.

 

Theres a better solution to this problem:



MOSFETs are inherently better for this, being voltage rather than current driven. This device will handle close to 3A at 60v in a SOIC8 package.

 

Why does anybody use a variant of an ancient 2N2222?

Because they don't know any better! Lesson learned.

 

Theres a better solution to this problem:

View attachment 286359

MOSFETs are inherently better for this, being voltage rather than current driven. This device will handle close to 3A at 60v in a SOIC8 package.

I'm only switching 25mA max though.

 

Datasheets from onsemi:

How did you find 2N2222A datasheet? When I searched onsemi it led me to the P2N2222A...

 

How did you find 2N2222A datasheet? When I searched onsemi it led me to the P2N2222A...

I just Google the part number. I downloaded that particular datasheet in 2021.

Attached is a datasheet from TI's 1973 databook for comparison.

 

I'm only switching 25mA max though.

With MOSFETs, you don't have to worry so much about leakage currents. You do have to be careful of ESD. I have some 2N7000 that now have high leakage current due to ESD events; and I was trying to handle them properly.