Alt-BEAM Archive
Message #07495
To: beam@sgiblab.sgi.com
From: "Jaroslav 'Lord Slayer' Pelan" pelanj@feld.cvut.cz
Date: Wed, 10 Nov 1999 14:23:27 MET-1MEST
Subject: [alt-beam] Re: solar head questions..
Hello
> the big cap has high resistance to high frequencies.
>
> Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> tel: (604)590-7493
> fax: (604)590-3411
I am not so sure about this. We were taught - capacitor almost
equals short circuit at high frequencies,
Zc=1/j*omega*c - the higher omega the smaller impedance(?)
( for u=Umsin(omega*t+fi) )
that's why i think they are used in the speaker boxes to trim down
the low frequencies.
theoretically i would recommend an inductor.
But attention - i'm studying, so i can be wrong
Greetings
JP
The EviL DaRKloRd SlaYEr
7496 Wed, 10 Nov 1999 14:28:11 MET-1MEST [alt-beam] Beam online tutorials beam@sgiblab.sgi.com "Jaroslav 'Lord Slayer' Pelan" Hello,
has anyone tried to make a bicore like shown in the Beam online
tutorial?
did it work?
mine didn't, just heated - and then i found out - the notch is on the
oposite side than shown in the t.
do you agree?
Also the Hbridge tutorial is wrong. Just have a closer look on the
transistor leads and you will see what i mean.
I tried to mail to Beam online twice, but i got no answer, so i write it
here. Please have a look there and tell me what you think.
Greetings
JP
The EviL DaRKloRd SlaYEr
7497 Wed, 10 Nov 1999 14:44:43 MET-1MEST [alt-beam] Re: Preferences on Tutorials beam@sgiblab.sgi.com "Jaroslav 'Lord Slayer' Pelan" Hello,
> Yep, I'll go for that too. Living in Denmark in Europe the only place that I can get
> 1381, 3904, 3906, 74AC245 are at Solarbotics (Now, there's absolutely nothing wrong
> with solarbotics - their support and customer care is excellent. However, it would
> be nice to know if there would be any alternatives). In Europe the components aren't
> marked the same way as in America, so I would assume that there would be
> alternatives to both the 3904 as well as the 3906 which supposedly are standard NPN
> / PNP transistors. Furthermore, as Rob said there ought to be alternatives to the
> 1381. I've heard of the TC54, but I haven't succeeded in finding anyone here in
> Denmark.
> Cheers and thanks alot.
>
> - Thomas
> --
> ---
I live in Czech Republic, and it is harder here to get anything here
than anywhere else in europe. But
3904 = 2N3904 cca 7c /pc (american cents)
3906 = 2N3906 cca 7c /pc
these are japaneese transistors, marked same as the US.
74AC(HC, HCT)245(240,14) cca 20-40c/pc
those can i get very well here, so you have to get them in Denmark
too. Try Conrad Electronics (germany, should be in Denmark too)
www.conrad.de - they also have solarcells
or GM electronics (Czech, but i don't know if they ship abroad)
you could try also www.ele.cz - online shop , Czech, mail them if
they ship abroad
the only thing i can't get are the 1381 - noone ever heard of them
here.
Greetings
JP
The EviL DaRKloRd SlaYEr
7498 Wed, 10 Nov 1999 15:35:59 +0100 [alt-beam] Re: Preferences on Tutorials beam@sgiblab.sgi.com Thomas Pilgaard Nielsen Jaroslav 'Lord Slayer' Pelan wrote:
> [snip]I live in Czech Republic, and it is harder here to get anything here
> than anywhere else in europe. But
>
> 3904 = 2N3904 cca 7c /pc (american cents)
> 3906 = 2N3906 cca 7c /pc
> these are japaneese transistors, marked same as the US.
Yes, I am aware of that. But since they aparantly are standard PNP / NPN transistors I
would believe - with my poor knowledge on electronics - that there would be an equivalent
in the BCxxx series, which is the most comon series at least here in Denmark. Anyone?
> 74AC(HC, HCT)245(240,14) cca 20-40c/pc
>
> those can i get very well here, so you have to get them in Denmark
> too.
Yes, The HCT's are no problem, however the AC deliver more Amp's as far as I am aware.
> Try Conrad Electronics (germany, should be in Denmark too)
> www.conrad.de - they also have solarcells
>
> or GM electronics (Czech, but i don't know if they ship abroad)
> you could try also www.ele.cz - online shop , Czech, mail them if
> they ship abroad
I will try that. Thanks.
> the only thing i can't get are the 1381 - noone ever heard of them
> here.
How about the TC54?
> Greetings
You too.
Thomas
--
---
"Fremtidens computere vejer maaske ikke mere end halvandet ton."
("Computers of the future may not weigh more than 3000 thousand pounds")
Popular Mechanics 1949
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