Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th April 2002, 12:19 PM   #31
diyAudio Member
 
Join Date: Feb 2002
Location: Germany
Angry second sources!

Hi Sonny,

this link is great! Other Mospec parts that have photos on their web pages have either MOSSPEC printed on them or their logo, neither of which looks even remotely like SEC or WEC printed in plain ordinary capitals. I would appreciate any hint as to who they are.

It was educating to look at their data sheets:
Compare 2SC2837 Sanken LAPT vs. Mospec 2SC2837:
f_T: 70 Mhz typ. vs. 10 min.
f_T-plot: typical, min, max vs. nothing
h_fe 50 min (with gain groups, but only on newer parts) vs. 30 min with no grouping
C_OB 60 pF typ vs. not specified

typical h_FE vs. I_C plots at 4 V: Mospec device begins to droop much earlier, no better than other maker's single emitter devices

typical I_C vs. V_CE: Mosspec looks slightly better but curves look like they were drawn with some artistic freedom

This is definitely an inferior part! Wonder why they dare sell that with the same part number.

Eric
  Reply With Quote
Old 9th April 2002, 02:58 PM   #32
tvi is offline tvi  Australia
diyAudio Member
 
tvi's Avatar
 
Join Date: Apr 2001
Location: Moonee Ponds, Vic, Australia
To the best of my knowledge
<a href="http://www.sec.co.kr/index.jsp">SEC = Samsung Electronic Co</a> ?
<a href="http://itri.loyola.edu/em/b_wec.htm">WEC = Wong's Electronics Limited </a></body> ????
<a href="http://www.fujiele.co.jp/eng/">FEC = Fuji Electronics Co</a>


Regards
James
  Reply With Quote
Old 9th April 2002, 03:20 PM   #33
diyAudio Member
 
Join Date: Feb 2002
Location: Germany
Hi James,

SEC=Samsung sounds good, only your link leaves my browser blank, probably a problem with the character set. I will try to access Samsung directly.

Your WEC seems to be a PCB foundry, so they wouldn't manufacture semiconductors.

Thanks anyway!

Eric
  Reply With Quote
Old 9th April 2002, 05:08 PM   #34
mlloyd1 is offline mlloyd1  United States
diyAudio Member
 
mlloyd1's Avatar
 
Join Date: Feb 2001
Location: illinois
Default Re: Dual transistors

Quote:
Originally posted by HarryHaller
All the SA1349/SC3381 I have on hand. I am hoping to put my finger on some more.
Harry:
I usually get mine from MCM Electronics; I just ordered some more today. Can't specify the grade though.
mlloyd1
  Reply With Quote
Old 9th April 2002, 05:46 PM   #35
Banned
 
Join Date: Feb 2002
Location: Dallas,Texas
Default SA1349/SC2281

While I appreciate all the offers of help, I do not need anymore of these transistors. Sorry for another of my poor attempts at humor. I know how serious we take or semiconductors.

My eyes may be playing tricks on me, but are those devices arranged in such a manner as to perform the old "Italian salute"?

Jocko

H.H.
Attached Images
File Type: jpg dual[1].jpg (12.0 KB, 311 views)
  Reply With Quote
Old 9th April 2002, 06:01 PM   #36
mlloyd1 is offline mlloyd1  United States
diyAudio Member
 
mlloyd1's Avatar
 
Join Date: Feb 2001
Location: illinois
heh, heh
OK, you got me.
My wife keeps telling me I need to take some vacation...
I think it's time to listen to her
  Reply With Quote
Old 11th April 2002, 09:47 PM   #37
diyAudio Member
 
Join Date: Feb 2002
Location: Germany
Default SEC?

SEC not Samsung. Found a Samsung part in my box, has the logo that looks like a tv-set stacked on top of the two others. It is the WEC transistor that looks more dubious to me, and I haven't made any progress finding out who that is.

Eric
  Reply With Quote
Old 17th April 2002, 08:28 AM   #38
diyAudio Member
 
Join Date: Feb 2002
Location: Germany
Default MJL3281A/MJL1302A

Still haven't found out about WEC except that the collector base capacitance seems to be 1.5x higher than in original Sanken parts I still had sitting in my shoebox.

I kind of avoided Toshiba 2SC3281/2SA1302 in the past, because in terms of f_T, beta linearity and output capacitance they were inferior to Sanken parts with similar power/current rating (even more so when compared to parts with slightly lower rating).

It turns out that this time, the second source, OnSemi, actually has a better data sheet (whether the parts are really better, I will find out when they have arrived).

f_T is specified at 30 MHz typ. for both parts (the 1302 only is specified at 25 MHz, even if the typical curve seems to show 28 MHz) but the typical curves show 50 and 40 MHz at 1 A, 5 V and even slightly more at higher current and voltage. Output capacitance is specified with a maximum instead of a typical value. Typical curves show slighly higher capacitance for PNP and lower for NPN than Toshiba typical values given in the table. Current gain lower and upper limits are slightly higher, but there are no gain classes as offered by Toshiba. Typical gain linearity plots look better than those for the Toshiba parts & in addition 20 V curves are given. I_C (V_CE) are not comparable because OnSemi plot only base currents in excess of 0.5A. And OnSemi offers "official" spice models


Eric
  Reply With Quote
Old 20th April 2002, 09:38 AM   #39
diyAudio Member
 
Join Date: Feb 2002
Location: Germany
Default On Semi MJL1302/3281A capacitance vs. Sanken

I have now received a batch of those transitors. DC current gain at less than 1 mA of collector current is 80-120, i.e already high and shows very little fluctuation (that is probably why there are no gain classes).

The collector base capacitance at 200 mV AC with no DC bias is 1780/1250 pF (all specimen identical to less than 5 pF). This value is consistent with the typical capacitance plot that is given for 1-10 V of bias which I simply extrapolated to 0 V. I have not checked my Toshiba parts which are still buried somewhere. Toshiba gives no curves, but typical values at 10 V are consistent with On Semi curves as explained earlier.

Now comes the big difference:
Original Sankens measure at 290 to 400 pF for the 2SA1186 and 250 - 280 pF for the 2SC2837 with the same tester which is a big difference considering their current rating is only slightly lower. Even if f_T is only slightly higher than for the Toshiba/OnSemi parts, the Sankens will present less of a nonlinear load to the drivers and they should be less prone to oscillations.

Cheers,

Eric
  Reply With Quote
Old 20th April 2002, 11:00 AM   #40
tvi is offline tvi  Australia
diyAudio Member
 
tvi's Avatar
 
Join Date: Apr 2001
Location: Moonee Ponds, Vic, Australia
So this is where that thread got to.

Samsung has changed their symbol a few times , the company has also been split into various bits and sold off (Fairchild accuired Samsungs power semiconductor group I think?)

The back of my Samsung monitor manufactured in 1998 has "(SEC)" on the back as well as the Samsung name in an ellipse, so Samsung is still my best guess.

Regards
James
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For sale Toshiba Transistors Xtreme Swap Meet 0 13th March 2007 11:10 PM
WTB toshiba transistors max29 Swap Meet 0 6th December 2006 07:53 AM
Authentic Toshiba Transistors audio89 Parts 0 9th November 2005 04:03 PM
Where to buy Sanken and Toshiba transistors weinstro Solid State 5 8th October 2003 09:58 PM
SSM2220, SSM2210 Ultra super low noise matched monolithic transistors pairs peranders Swap Meet 0 18th April 2002 07:58 AM


New To Site? Need Help?

All times are GMT. The time now is 05:18 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2