Re: TI-H: Electronics junk
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Re: TI-H: Electronics junk
>From: "Muhammed J. Galadima" <mj_galadima@hotmail.com>
>To: ti-hardware@lists.ticalc.org
>Subject: Re: TI-H: Electronics junk
>Date: Thu, 09 Jul 1998 05:39:00 GMT
>Reply-To: ti-hardware@lists.ticalc.org
>
>
>>A relay is basically an electrically operated mechanical switch. It
>>consists of two or more metal contacts and an electromagnet that, when
>>powered, will pull the metal contacts together and activate the
>>circuit. Its a fairly good way to get safe and relatively
>>uncompromisable electrical seperation between one circuit and another,
>>although I'd probably use an optoisolator and/or MOSFET depending
>>on the application; since relays have moving parts they can fail.
>>
>>There is no real '- volts' Current does not flow in 'different'
>>directions:
>>as the name suggests, e-'s flow in a circuitious path from positive to
>>negative (unless I have it backwards, and I probably do). Thus the
>>negative side of the battery can be considered an electron return, or
a
>
>yup, u got it backwards, electrons go from neg to pos...
>aren't there non-mechanical relays too? i'm not surebut I thought there
>were...
>
>>ground. A power ground for all intensive purposes is the negative side
>>of
>>a battery, but in RF circuits you may see an Earth ground (in which
you
>>literally connect that portion of the circuit to a copper rod in the
>>Earth)
>>and, every now and then, you'll see various other types of grounds.
But
>>in
>>battery circuits its usually necessary to connect the negative battery
>>terminal
>>to the ground return.
>
>exactly... I was reading somewhere (I might have forgotten a bit so
>correct me if I'm wrog) the ground is a reference voltage, in between
>the pos. and neg., so say you had 2 batteries connected in series the
>pos. terminal would be +V, the neg terminal -V, and in between the 2
>batteries would be the ground.
>
Yep that's right. That sort of power setup is mostly used for
amplifiers.
It looks like this:
+=======+BATT-=====GND=======+BATT-======-
I forget what it is called, though.
<snip>
Matt Butch
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