That's a very old design and it may be difficult to find components as bad as those old relics.Can 2SA1302 or MJL21193 be used as substitute ?
I think that's a flag for unnecessary roughness.probably anything better than a 741 is good enough.
AFAICR: All 2SA are PNP, most 2SB are PNP and all 2SC are NPN - I can't remember whether all 2SD are NPN.MJ4502 is available from Element 14 (or farnell). The price is not as high as I thought (USD 4.30).
If you can get Japanese transistors locally, those with Ic=30A and Vceo>100V and Ptot>150W are as follows:
2SB1232, 833, 694(25A)
2SA 1043, 1044
Most of the high current transistors are in the 2SD NPN category. If you can find one that uses NPN power transistors or better still power MOSFET. Then the component cost would be much less.
Check their datasheet online and see if they are darlington pair and their casings suit your purpose. Some of them have internal diode on CE.
Allen
p/s: sorry, the PNP low frequency should be 2SBxxx. Let me check again.
Pretty sure that at one time or another I've encountered an NPN 2SB - but extremely rare.Hello Ian,
The 2sa,2sb are jis codes:
SA: PNP HF transistor
SB: PNP AF transistor
SC: NPN HF transistor
SD: NPN AF transistor
SE: Diodes
SF: Thyristors
SG: Gunn devices
SH: UJT
SJ: P-channel FET
SK: N-channel FET
SM: Triac
SQ: LED
SR: Rectifier
SS: Signal diodes
ST: Avalanche diodes
SV: Varicaps
SZ: Zener diodes
Here is the full text in the following link:
http://www.elexp.com/t_tranmk.htm or
http://www.gae.ucm.es/~padilla/extrawork/transistor.html
Bertus
Originally the designation was Japanese, but has since spread Asia-wide. There's bound to be the occasional aberration.Hello,
Yes that could be so.
Exceptions prove the rule.
Bertus
I have lots of 2SB727 darlington power transistors from old OKI teleprinter machines. It has a 2SDxxx NPN matched pair too.Pretty sure that at one time or another I've encountered an NPN 2SB - but extremely rare.
The European BU prefix transistors were high voltage types that you might find in a flyback SMPSU or horizontal output. Generally rated at least 1000V, but none anywhere the 200W you want.There are a lot of old Samsung CRT monitors where people just throw them away. Some have 20" screen but most are 17". I savaged a lot of their PCB and found lots of C945 transistors inside. Some of the chips are TDAxxx and some made by Samsung.
BTW are there any BDxxx or BUxxx transistors with Vceo>=100V, Ic=30A and Pc>=200W?
Allen