I'm not familiar with this 'S' logo, never seen before. Is there anyone who knows about the origin of these transistor??
The "S" on the 2N5551 looks a little bit to rounded for the Signetics logo.
Although i don't know about their manufacturer but looks good to me. Hfe is between 110-140 for both sex, copper leg & slightly magnetic.
Soldered pins and sanded plastic ,at least looks to me like that , maybe fake ? Asian source maybe ?
Not sanded or soldered. I have seen fake to92 transistors before but these are not like those. Maybe only God knows what i have.
I started this thread so we can try to find out 😉 Anyways, according to my source (a friend of mine) that 'S' logo belongs to a Chinese company. He had the datasheet in his PC but lost it somehow.
Such price is cosmic absurd , who can buy these from there ,when even local sellers have them ...
Maybe one of these manufacturers ... link . If logo was too big to fit on device ,they maybe shortened it to S letter . One of possibilities is semtech , but datasheet contains no exact picture of logo and its placement position or marking .
My friend they "Semtech" have history for producing BJTs,
Those 2N5551/2N5401 are Semtech NOS,
They have changed their logo S/SC/ST
Those 2N5551/2N5401 are Semtech NOS,
They have changed their logo S/SC/ST
Probably but i'm still not convinced. Anyway i found another transistor with same logo. Courtesy Google photo.
There are two or three more company that might be. Samsung, Secos & Can sheng with a big orange 'S' on their logo.