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

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.


>
>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/
>


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