![]() ![]() Looks like a winner, how about 2SC945? 50 VDC, 150 mA, 250 mW and gain from 40 to 700. I call them "the book of lies" and for good reason too. Remember, you are not allowed to use the ECG or NTE parts, nor are you allowed to use either replacement "manual". ![]() Now you only need to select a replacement with the same pinout and similar ratings. The following ratings are absolute maximum values except for gain and things like that, those will be typical values.Ģ5 VDC C-E, 200mW (at 25° ambient), collector current is 100 mA maximum and a beta of approx. Just making sure we are talking about the correct parts here.Ī quick look with Google presents the following data for the 2SC371. Those are for H705 and H706? The complimentary parts are H707 and H708 (2SA562Y) and these are the current limiting transistors - right? of course the more expensive the part, the more they can charge the customer for the repair. I used to use 2SD870 in video monitor service - $4.10 at MCM and the NTE89 sub for it is $8.45. In that MCM catalog, the 2SC1328 was 9 cents, while the NTE199 was $1.06. The amp certainly won't meet its power specs or reliability.Īnd the NTE stuff costs more. That NTE power xstr won't match up to anything. If one xstr turns on a bit lower than the others it hogs current, and conversely if one turns on a bit higher, the others do its work. When I have a row of six power xstrs in an output stage, I need them to share current. I work in pro audio, and this is especially important in high power amps. They make - or at least supply - a number of transistors, and they list the ones that most closely resemble your parts among those they make. I also bought the Tower's FET selector as well The internet is great, but I still like to browse through specifications in a book now and then.Don't labor under the misconception that the NTE stuff is some sort of exact replacement - it's not. For GBP12, it's a bargain so I have placed an order. I just took a look on Amazon.the Tower's International Transistor Selector is still available The latest revision seems to be December 2008 and it includes SMT transistors. Some circuits just will not behave without a very close equivalent part. This is crucial for good equivalent selection. One thing I did learn all those years ago, was to read the schematic and decide how critical the components specifications were to correct operation. SMD stuff is too modern for it though so I then have to fall back to internet searches. The internet has changed searching for equivalents but I often find the Towers book faster as I grew up with it and know many favourite equivalent transistors. It lists the transistors specifications and any equivalent (but not all) You can flick through various ranges of transistors and select a suitably specified part. I still have my copy from the 1980's and it still serves me well. In the UK when I worked as a 'Saturday lad' in an electronics shop, I used the 'Towers Transistor selector' book. Substitution of RF power devices needs to be approached with a great deal of caution,& preferably with a Spectrum Analyser on hand. Modern devices as a rule,are better spec'd than older ones,so a common modern type may replace an old special type. In more complex circuits,have a look at what devices other manufacturers use in similar circuits-there may be a common device which will do the job. If it is something simple,like a lamp,LED,or relay driver,you can probably replace it with a more common type without any drama. If you can't find a listed equivalent,one good philosophy is to look at the circuit the device is used in. Not only did they often disagree,but by the time you had tracked from one book to another,the specs on the final one you turned up were many times quite different to the original. At one of my earlier jobs,we had semiconductor equivalents book from several sources. Good luck finding anything that will do that!(though it must be out there somewhere) Many times the equivalents shown in the various books are harder to find than the original component. ![]()
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