Subject:
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re: ztx614
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 19 Mar 1997 09:51:06 GMT
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Original-From:
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Stefano Nardone <stefanon@promos/avoidspam/.it>
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Viewed:
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1587 times
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> If I have interpreted the schematics correctly almost any npn can be used for
> the ztx614. The 614 simply provides ground for the IR transmitter with a
> collector current of about 3ma. The base current is set by the 10k R to about
> (5/10k) 0.5ma. If I have calculated f=1/2*pi*RC for the TOC5 enabled
> oscillator, then the frequency max of the IR output is in the kilohertz range.
I think it must better be a darlinghton and it must support enough current: if
you want to get 0.1A or more pulsed current in the IR led, the transistor must
have a rather high current gain, more than that of an ordinary npn trans (by
the way the base current is less than 0.5mA). Probably an N-MOS switch with the
right switching V and enough current (BS170?) can be better...
>
> This all means that almost any medium power npn can be used! I am
> building my own board and could not find the part either. I am going to
> finish my board tonight and I am substituting a 2N3904 for the ztx614.
8^) I too substitued it with an ordinary NPN transistor... but until now
haven't used the IR interface
regards
stefano nardone
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Message has 1 Reply:
 | | re: ztx614
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| (...) I just looked back to the IR transmitter schematic... The 1K res + RED LED you see there is for the only purpose of having a visible feedback of IR transmission. The IR Led and it's limiting resistor (if the case) will be connected in series (...) (28 years ago, 19-Mar-97, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | re: ztx614
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| If I have interpreted the schematics correctly almost any npn can be used for the ztx614. The 614 simply provides ground for the IR transmitter with a collector current of about 3ma. The base current is set by the 10k R to about (5/10k) 0.5ma. If I (...) (28 years ago, 17-Mar-97, to lugnet.robotics.handyboard)
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