Hi all Just a simple question from a electronics newbye. I was wondering if is possible to harm anything if I have been running too many things off one voltage regulator for a long time, other than getting the reg hot. Thanks a lot
-Kit
"kitmor" wrote in news:1140458589.194766.156030 @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
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