Newbye electronics question

@g14g2000cwa.googlegroups.com:


Regulators like the 7805 only supply 1 amp of current.  I never heard of a
gizmo that was damaged because it didn't get enough juice before.  

The regulator itself (I think?) might get fried if you short it out (having
no resistance- a piece of wire).  But you're talking about the opposite
(having too much resistance- several components).  

So, if all your circuits are working fine, don't worry about it.

Incidentally, you should have a heat sink on the regulator, because keeping  
it red hot all the time may damage it.

No, by adding more "things" in parallel to the regulator, the resistance
is lowered and eventually short-circuited. So the answer is, that your
regulator will overheat an eventually fail (unless your transformer or
battery or whatever runs out of juice first).

As a rule of thumb, none of the components in your circuitry should get
so hot that you can touch it anymore.

     Actually, no.  The 78xx series of regulators have full protection
circuitry.  From the data sheet: "Each type employs internal current
limiting, thermal shut down and safe operating area protection,
making it essentially indestructible."  If overloaded, the output voltage
will drop below the regulated value, but the regulator will be undamaged.

     The problem with putting "too much stuff" on one regulator is
that one of the loads can interfere with the regulation for the others.
If you have something that's electrically noisy, like a motor, or
something that intermittently draws high current, like a sonar,
the other loads on the same regulator will see voltage variations.

     Although it's a bit dated, reading "The Art of Electronics",
by Horowitz and Hill, is a good way to get a good sense of how
power regulation works in the real world.

                John Nagle
                Animats