MadModder
The Shop => Electronics & IC Programing => Topic started by: johnstij on November 20, 2010, 05:28:58 PM
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Hi. Can any one suggest an alternative/equivalent to a BC848 NPN transistor.
Thanks . Ian
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Hi Ian ,
the transistor is basically a surface mount version of the BC108
if the pcb design makes it possible ,you could try a TO92 plastic NPN transistor like a BC547 or BC548 (can try maplin for this)
otherwise try ebay , RS components or farnell for a BC848
what is the transistor used in ,and how many do you need ?
I may have one or two SMT transistors that may work
John
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Hi johnstij
I have some, BC848B. The B suffix is for hfe range, so if yours lacks the suffix they will be perfect. How many do you need ?
picclock
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Hi.
Thanks for the replies.
I'm trying to control the speed of my CNC mill spindle. It runs on Mach 3 software. The circuit i found on the Mach 3 forum converts a PWM signal to analogue 0-10v DC which goes to the motor VFD.Not sure why the circuit specifies a BC848 as he uses a TO92 case transistor built on vero strip board (as I plan to)
This link takes you to the document, the circuit is on page 11,
http://www.cjh.com.au//PWM%20Spindle%20Control%20using%20Mach3.pdf
A copy of the circuit is attached.
Thanks Ian
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Hi.
Just looked through my small box of transistors and found a BC107 & 107B do you think either of these are suitable.
Thanks Ian
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Hi Ian ,
I would expect the BC107 or BC107B to be OK
in fact almost any low power silicon npn transistor is likely to work
take a look at the " universal npn transistors " used by Elektor magazine in their simple projects
search for " TUN TUP DUS DUN "
John
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Hello John
the following links may be useful for future lookup
http://www.datasheetcatalog.com/datasheets_pdf/B/C/8/4/BC848.shtml
many other data sheets available here.
Also
http://talkingelectronics.com/projects/TransistorData/TransistorData-P1.html
Cover a large range, if you are looking for a Japanese transistor starting C****
then add 2S in fron making 2SC****
When choosing a substitute try to match or better the characteristics.
If it is for very high frequency( 10meg hertz plus) work then some times only a correct replacement will work satisfactory, but this is rare.
I am sure other folk may have other opinions, but I have found this approach works for me.
Trev
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Hi Trev ,
thanks for the info
two usefull links
while a search for data for a transistor very often links to datasheetcataloge.com
the talking electronics page is one i've missed
the link to philips and the smd marking data I've just downloaded
until now I had no idea what a 2BJ transistor was
my DCA55 component analyser is good , but it does not give part numbers!!! (its a BC849b by the way)
yes you are right , japanese transistor numbers only make sence if you know they don't print the 2S prefix
on the part
John