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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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20th Jan 2022, 1:47 pm | #1 |
Diode
Join Date: Mar 2021
Location: St.Helens, Merseyside, UK.
Posts: 3
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BC650 equivalent
Hi, I'm trying to track down a couple of BC650 transistors to build a small dipole preamp front a R. A. Penfold aerial projects book. Having recently retired I thought this would be a good start to get back into electronics, particularly radios. Can anybody recommend a good transistor equivalent book or 2. Google search doesn't throw up any supplies of the transistor apart from Cricklewood electronics but seems they have no stock. thanks
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20th Jan 2022, 2:53 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,998
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Re: BC650 equivalent
Historically, the default transistor-equivalents book was T.I.T.S. - Towers Internaltional Transistor Selector. Copies [there were several volumes] occur occasionally on the usual auction-sites.
BC650 is a fairly mundane transistor... BC650=Vcb=30v vce=30v veb=6v Ic max=100ma P.TOT=625mw Ft Min=100m Hfe =400min Something like a MPSA18 would work. Mouser-UK have them for 73p each,
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20th Jan 2022, 8:56 pm | #3 |
Diode
Join Date: Mar 2021
Location: St.Helens, Merseyside, UK.
Posts: 3
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Re: BC650 equivalent
Thanks very much for the reply, appreciate it.
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21st Jan 2022, 2:20 am | #4 |
Nonode
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,335
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Re: BC650 equivalent
I got a copy of TITS from the forum. If you ask in the 'wanted' section, someone might have one they can send you.
It's been useful to check whether transistors I have in my box are what I need, even if the circuit asks for something else! It seems lots and lots of these are basically interchangeable unless a very specific parameter is what the circuit's designed for. Another resource I've used, especially for MOSFETs which my TITS doesn't cover, is https://alltransistors.com/ Search for the transistor number, choose the variant and at the bottom of the listed specifications you'll see "xyz transistor equivalent substitute". Clicking that will give you a long list of transistors that are close in various ways. More comprehensive but can be less convenient than a book. I find the TITS index of base types and pinouts to be invaluable as well. |
21st Jan 2022, 2:35 am | #5 |
Diode
Join Date: Mar 2021
Location: St.Helens, Merseyside, UK.
Posts: 3
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Re: BC650 equivalent
Thanks
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21st Jan 2022, 5:57 pm | #6 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,573
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Re: BC650 equivalent
Hi.
In my Jaeger Elektronik databook it lists the commonly available BC550 as a suitable replacement for the BC650. Regards, Symon |
21st Jan 2022, 11:59 pm | #7 |
Hexode
Join Date: Sep 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 474
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Re: BC650 equivalent
My version of TITS (Update 4, from 1990) lists the BC650 but does not suggest any equivalents.
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22nd Jan 2022, 9:12 am | #8 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,662
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Re: BC650 equivalent
Here's a substantial list of equivalents - https://alltransistors.com/crsearch....=400&caps=TO92
Andy.
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28th Jan 2022, 12:27 pm | #9 |
Nonode
Join Date: Jan 2009
Location: Bristol, UK.
Posts: 2,062
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Re: BC650 equivalent
It seems the 'alltransistors' site recommends a darlington substitute
I suppose it might work!! I would guess, for an antenna preamp, the best option is something with high gain at HF and low noise, and it probably (?) doesn't need to dissipate a lot of power so maybe a 100mW device is enough - since a physically smaller device is likely to push the HF gain up. dc |
28th Jan 2022, 2:45 pm | #10 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,947
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Re: BC650 equivalent
It seems to be a pretty bog standard transistor. I imagine the original designer used it simply because he had some to hand.
I would expect the usual BC548/2N3904 to work just as well. |