Counterfeit 2N3055?

I just wonder, why would anyone spec a 2N3055 these days anyway?

Thanks, Rich

I haven't looked at the price recently but for a 115W TO-3 npn general purpose power transistor it may actually be very cost effective.

Beware of the difference between the 2N3055 and 2N3055H.

Graham

They were a damn sight pricier than 2N3055s I can tell you. I still have part of a tray of them left over from when I did repairs more often. Actually not a bad device at all for its day. It's why 800W per channel became a sort of 'standard' for PA/SR power amplifiers into 4 ohm loads for ages.

Graham

Eeyore wrote in news: snipped-for-privacy@hotmail.com:

Fair enough. Was just looking at Digikey's 300 just now, looked decent price to me, but singles shot up to 2x, even 3x.

"Eeysore the Professional LIAR "

..... Phil

Just max voltage, I think...? 60v vs. 100v

I've never seen a 100V Vceo 2N3055. No, it's speed. RCA's original 'Hometaxial' (single diffused) process yielded a durable (large SOA) design with 800kHz fT, Motorola's epitaxial was less durable but had an fT of ~ 2.5MHz.

A similar problem existed with the 2N3442. It could cause amplifiers to be unstable if the wrong 'variety' was sourced. A notorious cause of problems with kit amplifiers back in the mid 70s.

"Summary:The 2N3055 power transistor was introduced by the Radio Corporation of America (RCA) in the early 1960s. It was one of the first silicon power transistors, offered unrivalled second breakdown immunity and found many applications particularly in audio power amplifiers and linear power supplies. Other companies tried to copy it with varying degrees of success: one company acknowledges it now by naming a power MOSFET after it. We trace its history, manufacture and eventual decline against pressure from competing technologies. Modern simulation tools have been used to investigate the operation of the device which illustrate its good, and not so good, features. We also relate its geometry to a SPICE model. Neither of these tools would have been available to the original developers. We propose that this transistor be given a place in the archives of history, ranked alongside other famous devices of the 20th century such as the 300B tube."

"You can build good amps with 2N3055/MJ2955's and they are pretty cheap.

I've built a

Graham

"Eeysore"

...... Phil

It was my error, freely acknowledged. As used in the RSD / Studiomaster 800B and

Graham