Crossing NTE transistors to industry numbers

You think of suitable numbers and then check them in the cross-reference.

I started doing that back in 1974 with an HEP replacement guide, and it was a good way of getting a basic idea of what a device was. Saved having to check multiple books just to see whether a transistor was NPN or PNP. The cross-reference section in the NTE guide is far larger than that old HEP guide, and of course it's now faster when you can do the look up electronically.

Michael

Lenny,

The older Dalbani catalogs had a reverse NTE cross ref. in them. I don't know if they still do, or even if they're still in business.

Mike WB2MEP

Yeah, they're still in business, but they don't seem to carry NTE any more.

Just using the transistor cross reference, I get 2SD371 Using my Towers book, BDY20 2N3055 (HAhAhA)

Using my Japanese cross booklet for, I get 2SD716 2SC1667

I would check out the specs first on the last two.

off my page

greg

Len,

The 2N6254 is a 100V, 15A, 150 watt transistor. MCM Electronics

Reverse cross referencing is tricky, as usually the 'universal subs' choose one transistor to replace many. So, comparing the 2N6254 to the NTE 181: original here:

They are both rated for 100V

The NTE is rated for 30 amps instead of 15A

The NTE is rated for 200 watts instead of 150 watts.

Unfortunately, by doing a "reverse look up" you don't know if the other device is good enough, for example, it might be rated only 12 amps. So, you have to carefully compare the device you are replacing (2N6254) with the device that you want to replace it with.

While in general, higher break down voltage, higher current and higher dissipation ratings are OK, they also DON'T tell you about the gain of the transistor, or the frequency response. If you have a bunch of output transistors in parallel, they should all be of the same type, and in a perfect world, gain matched as well, as you want the load spread evenly across the bank.

The frequency response can also be a problem. If it is too high then the amp may have problems with oscillations.

When using transistors that I can't curve trace, I try to use the same lot number in the bank. Sometimes this requires buying a few extra transistors.

Regards, Tim Schwartz Bristol Electronics

Just goes to show you, after checking any replacement guide, verify the specs. That 2SD371 shows ony 6 amps. Sometimes you can up the current if the voltage is over rated. Back referencing the 2n3055 you get

ECG130 2N3055 2N3715 2SD878 2SD492

ECG = TCG...

John :-#)#