Re: TI-H: Electronics junk
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Re: TI-H: Electronics junk
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
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.
Any of the real EEs on the list with a more theoretical explanation can
feel free to jump in, I'm not very familiar with all of the theoretical
aspects
of electrical engineering.
Bryan
Larry G Currie wrote:
>
> I was looking at some schematics and have 2 questions:
> 1. How does a relay work? I know it's some kind of switch but thats all
> 2: IN these schematics, it shows where +12V goes into the system but
> doesn't show where -volts goes. Should it go where the schematics show
> ground (I think it's ground, It's a inverted pyramid made with horizontal
> lines or a tornado) eg.
> --------
> ------
> ----
> --
>
> Larry1492@juno.com
>
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--
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.bridges.edu/horizon/
References: