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General => General Technical Chat => Topic started by: Neomys Sapiens on July 19, 2020, 10:58:01 pm

Title: Power Transistor Data sought
Post by: Neomys Sapiens on July 19, 2020, 10:58:01 pm

Does anyone have access to a datasheet of a very large Siemens power transistor labeled BTr F 0111 ?
(It is stud mounted with M12 thread and 27mm across flats)

Title: Re: Power Transistor Data sought
Post by: Chris_Walch on July 20, 2020, 04:27:25 pm

The prefix BT is commonly used for thyristors, but I didn't find any with your markings.
Please post a picture of the component.

Title: Re: Power Transistor Data sought
Post by: Neomys Sapiens on July 20, 2020, 07:41:30 pm

Marking details:
BTr over F0111, around 90° to the right: 5A, around 45° left: symbol of NPN transistor, around 90° left: SH logo over SIEMENS

Stamped on one flat of hex nut: A2550

And here it is:

Title: Re: Power Transistor Data sought
Post by: Benta on July 20, 2020, 08:13:13 pm

Wow, that looks really 60s, perhaps early 70s.
A wild guess would be an automotive part for ignition coil drive.

Title: Re: Power Transistor Data sought
Post by: Neomys Sapiens on July 20, 2020, 08:51:52 pm

@Benta: Although the fusion of the various parts into the Siemens AG was effected in 1966, the Logo with the S and the H was purpotedly in use until 1973, when a unified Logo was in use. This would support your assessment.