sci.electronics

Michael Schorpp

unread,

Jan 21, 1995, 11:25:00 PM1/21/95

to

-> I am trying to use a old 286 to run electrical appliances.
-> The computer switches up to 8 devices on/off via relays. (
-> using the parallel port ).
->
-> The problem is that the 286 only puts out 3 volts and I can
-> find no relays that have a 3v switching voltage ( worded
-> correctly?? ).

The output pins on the parallel port are TTL compatible and so can only
handle a few milliamps. Relays generally take a lot of current so what
you could do is buffer the outputs of the parallel port with transistors
or use a TTL buffer chip.

Another possibility is to use an optocoupler together with a TRIAC. I
believe the MOC3011 can be directly driven from the parallel port
although this will be pushing the TTL outputs somewhat. The MOC3011
should be wired so the TTL output pin sinks the current from the 3011.

-> Is there any other way to control devices using a PC.

There are a multitude of ways to do this. There are many commercial
products out there such as X-10. I homebrewed one simple circuit that
would allow a PC to be used as an IR learning remote. With the software
I wrote I could record, store, display and playback almost any IR
signal. The program is public domain and includes source code so that a
customized program can be written with any standard C compiler.

Mike.

Subramaniam Balendra

unread,

Jan 26, 1995, 8:00:45 PM1/26/95

to

i am interested is designing a power supply of 2kw output at 20,000KHz to
drive ultrasonic equipments. can anyone help me witha circuit diagam.

Alpha Hou

unread,

Jan 26, 1995, 9:09:45 PM1/26/95

to

Anyone knows how to get the FCC Specification for 900 MHz
Cordless phone? I want to get the most updated Specifications for that.
Should I have to purchase from them directly? How?

Alpha

Nick Gray

unread,

Jan 30, 1995, 1:25:13 PM1/30/95

to

In article <3g9gjt$h...@pcnet1.pcnet.com> bale...@pcnet.com (Subramaniam Balendra) writes:
>Xref: nsc sci.electronics:110836
>Path: nsc!voder!apple.com!gallant.apple.com!trib.apple.com!agate!news.ucdavis.edu!library.ucla.edu!europa.eng.gtefsd.com!news.mathworks.com!news.alpha.net!uwm.edu!vixen.cso.uiuc.edu!howland.reston.ans.net!nntp.crl.com!pcnet.com!pcnet.com!not-for-mail
>From: bale...@pcnet.com (Subramaniam Balendra)
>Newsgroups: sci.electronics
>Subject: sci.electronics
>Date: 26 Jan 1995 20:00:45 -0500
>Organization: PCNet, Connecticut's Internet Provider
>Lines: 2
>Message-ID: <3g9gjt$h...@pcnet1.pcnet.com>
>NNTP-Posting-Host: pcnet1.pcnet.com
>X-Newsreader: TIN [version 1.2 PL2]

>i am interested is designing a power supply of 2kw output at 20,000KHz to
>drive ultrasonic equipments. can anyone help me witha circuit diagam.

Call National Semiconductor Customer Service at 1-800-272-9959 and ask for the
Power Management data book and application notes.

-----------------------------------------------------------------------------
| Nick Gray National Semiconductor Corporation |
| Opinions expressed are those of the author and do not necessarily reflect |
| reflect the thinking or opinions of National Semiconductor Corporation. |
-----------------------------------------------------------------------------

Richard Steven Walz

unread,

Feb 3, 1995, 8:43:35 AM2/3/95

to

In article <60.6769.42...@canrem.com>,

--------------------------------------------------
An X-10 note. For those interested in knowing the X-10 theory of operation
and how to use your PC to talk to them, see our mini-ftp site at:
ftp.armory.com /pub/user/rstevew/X-10 and other subdirs and other users as
well for interesting stuff.
-Steve Walz rst...@armory.com