US transistor equivalents.

[G6Tanuki]

Does anyone have a reliable and consistent guide that matches US "NTE" "SK" and "HEP" transistor-codes to either JEDEC or Japanese equivalents?

From what I can work out, "HEP" was a Motorola series of transistors aimed at hobbyists rather than professionals, SK was RCA's similar offering, and "NTE" was a rebrander who offered a range of parts from different suppliers.

What is a SK3030 or a HEP801?

I really wish more people had adopted the "Elektor"-magazine approach for the transistors/diodes in their designs.

TUP TUN DUG DUS.

Transistor, Universal, PNP
Transistor, Universal, NPN
Diode, Universal, Germanium
Diode, Universal, Silicon.

[paulsherwin]

I normally rely on Towers for anything which isn't obvious from a quick Google search, but even Towers doesn't list the two types you mention.

[Wendymott]

Some suppliers use "in house" numbering... to stop the likes of me, reverse engineering / copying things.
Thats my theory anyway

[Mike. Watterson]

I had thought NTE was Newmarket, Pye's transistor division?


Early Germanium types had a big spread (hence sorting with coloured dots or suffix, which had been done with triodes in the 1920s for audio output to indicate grid bias). Also the devices were much less standardised between makers.

It's later when there are 2N, 2S, AC and AD prefixes that equivalents are meaningful. In the early days RF/IF, AF, Audio out were the main categories and all were PNP. Later NPN for complementary audio without transformers.

In the very early days really IF, AF and Audio out, hence car radios using valves and transistor inverter, then 12V HT on valves and Germanium power out for audio. Low IF like early valve superhets and even DF97 (VHF) and DK96 (HF) "front ends" as the transistors barely did IF. Hence lack of equivalents.

1950 to 1958 transistors were like 1920 to 1931 valves.

Probably I'm wrong on NTE and Pye used NKT.

[paulsherwin]

Yes, you are thinking of NKT which was Newmarket (Pye). NTE are American.

https://www.nteinc.com/

[Maarten]

NTE and ECG substitutes were as close as you would get to TUP/TUN etc. They selected their substitutes to cover as much originals as possible. That strategy doesn't always work and also I think they were often more expensive than when you picked a substitute yourself.

[Terry_VK5TM]

HEP801 comes out to a JFET according to:-

http://www.weisd.com/test/GenericPar...editid1=HEP801

And the SK3030 comes out to a 1A 600v diode according to the same place.

Don't know how accurate it is though.

Edit - has the NTE numbers too.

To answer your original question, the NTE Quickcross program (free from NTE ) lists all the equivalents but it is a looooong time since I have used it.

[G6Tanuki]

Thanks for the suggestions: these are 1960s/1970s US designations listed in ham-radio projects.

From the circuit [an early direct-conversion receiver] the SK3020 is a low-power junction-transistor, I'm guessing silicon. Hopefully something like a BC109 will do [there ae 3 of them in a DC-coupled audio amplifier/selective filter fed from the balanced detector, the design notes say that the SK3020 was 'chosen for its low noise and high gain' which makes sense since the three of them are amplifying only a Microvolt or so of audio].

Likewise the HEP801 is a JFET, used as the local oscillator. With luck something like a MPF102 or U310 will work. Strange thing is, while some of my online searches show HEP801 as a JFET, others show it as a TO3-cased power transistor (which is most unlikely to be the device-of-choice for a 14MHz VFO).

Alas I threw out all my copies of Towers around the turn of the millennium when I moved office.

JEDEC 2N-style numbering is _so_ much easier - you know where you are with a 2N3053 or 2N3771 !

[Terry_VK5TM]

SK3020/NTE123 TRANSISTOR NPN SILICON 75V IC-0.8A TO-39 AUDIO AMP

BC109 will be somewhat underrated depending on the circuits operating conditions.

[Maarten]

Originally Posted by G6Tanuki

JEDEC 2N-style numbering is _so_ much easier - you know where you are with a 2N3053 or 2N3771 !

But do you know with a 2N2955?

Problem with the JEDEC system is that you can't spot most mixups from the numbers either. It's only a slight improvement above the SK, ECG etc. systems in that the number of junctions is included and it's documented a bit better.

[chriswood1900]

Just spotted this thread, out of interest I looked up the the two items in my US Howard W Sams guide for service engineers which gave the following info.
SK3030 = NTE116, ECG116, RCA -SK3313 and a Radio Shack 276-1104 N- Channel JFET
HEP801 = NTE312, ECG312, RCA SK9157 Radio Shack 276-2055 600V 1A RECTIFIER DIODE
The later RCA codes show as available on ebay in the US.
More info here on coding conventionshttps://www.logwell.com/tech/components/ECG_NTE_SK.html
Farnell list the NTE116 as General Purpose Standard Recovery Diode, 600 V, 1 A, Single, 1.1 V, 30 A and a NTE312 as a BF256B
Hope this is of interest.
Chris

[chriswood1900]

Whilst experimenting just found this link to NTE numbering http://nte01.nteinc.com/webforms.nsf/qcsignin?openform
If you put the NTE number in the search box it returns with a data sheet link.
Might be useful to bookmark for those who wanted a reliable source of NTE data.
Chris

[Argus25]

Originally Posted by G6Tanuki

Does anyone have a reliable and consistent guide that matches US "NTE" "SK" and "HEP" transistor-codes to either JEDEC or Japanese equivalents?

In general the manuals that I have found the most help are the VRT manuals volume 1 & 2, TP, I have the Tech/ECA Asia Pacific edition, Tech Publications Singapore.

They list practically all known transistor and diode types going right back to the original series of each type & manufacturer and link them together as close equivalents across nearly all known Japanese, American , European & English types.

As just one example, this is where I discovered that a 2SA358 was a close match to an AF118 and SFT162. Also, 2SA228, 2SA249 & 2SA250 also very close. Difficult data to find elsewhere.

Despite the wealth of data there, little on NTE, SK and HEP.

[AC/HL]

I have a Motorola cross reference book aimed at CB users, organised by manufacturer so there's no overall index. However the HEP references are all prefixed by a letter. E.G. for Cobra a 2SA495 is an HEP S0013. At a glance there are no European transistors featured.

[Terry_VK5TM]

Originally Posted by Argus25

In general the manuals that I have found the most help are the VRT manuals volume 1 & 2, TP, I have the Tech/ECA Asia Pacific edition, Tech Publications Singapore.

Got those too.

Once had access to ECA's software version, much better than the books - much more actual data on the devices.

[Maarten]

Maybe not the same software version, but the online system isn't half as useful to me for finding equivalents as the vrt books.

[G6Tanuki]

I'm going with the MPF102 as a substitute for the HEP801 in the VFO.

A bit of research shows that an equivalent for the SK3020 I need for the 3-transistor amp is the RCA 40233 - and indeed the direct-conversion-receiver circuit shown using one here -

https://www.radiomuseum.org/tubes/tube_40233.html

seems to be a very close copy/reworking of the circuit I'm recreating!

Now, where to get Hewlett-Packard hot-carrier diodes for the mixer

[Restoration73]

https://uk.farnell.com/stmicroelectr...ngdom%2Fsearch