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short circuit detector

got another one for u dudes to gawk at the insane simplicity. =)

123315437_1341794062835314_4616136031296418354_n.jpg

I replaced the picture for a better one, more descriptive and in voltage divider mode instead of current divider to save overloading the led.
 
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Harald Kapp

Moderator
Moderator
What is your power supply going to be?
With only 1 Ω in series with the LED you'll need veeery tight regulation of that supply otherwise the LED will burn through quickly and your "detector" will show a permanent short circuit.
 

Harald Kapp

Moderator
Moderator
9 V to an LED with 1 Ω series resistor will result in ~7 A current.
Don't worry about draining the battery: The LED will burn through much quicker.
 
but its 4.5 volts cause its in a voltage divider, and you can light an led off a battery with no resistor fine, with the volt reduction I think would be about safe.
 

Harald Kapp

Moderator
Moderator
but its 4.5 volts cause its in a voltage divider
Before you edited your image there was only one 1 Ω resistor, you "secretly" added a second one.
Even with two 1 Ω resistors current through the LED will be ~ 3.5 A, still way too high.
you can light an led off a battery with no resistor fine
Yes, once, for a few milliseconds.
with the volt reduction I think would be about safe.
Do not think, do the math -> no this won't work.
 
The second resistor, makes it a voltage divider, so only half the power of the battery hits the led. it should be safe. but i spose, I could be wrong...

The fact that the invention actually works is not as important as the led frying with the wrong resistance, is it.
U guys help keep my work safe from plagiarists, thankyou.
 
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Why? it cant be because it doesnt work, because it does.
Is it because its so easy everyone already knows?

Have a look at this circuit on the internet-> (these guys dont know...)

https://www.instructables.com/Short-Circuit-Detector-Part-1/

Its overcomplicated, and I doubt it even works.
You guys are lucky you have me here to point out these things to you. (im sorry if it offends the ego a little tho...)
 
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If I count my blessings (albiet in an unavoidable circumstance.), I guess so.

Im just letting you guys know that a voltage divider is enough to detect short circuits. isnt that clever.
 
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Have a look at this circuit on the internet-> (these guys dont know...)
https://www.instructables.com/Short-Circuit-Detector-Part-1/
Its overcomplicated, and I doubt it even works.
It will do something, but not something useful. In this circuit, the beeper is on constantly until the probes are connected to a resistance of something less than 10,000 to 100,000 ohms. At that point the transistors attempt to place a dead short across the battery to turn *off* the beeper.

It is clear from the schematic what the intent of the design was, but he got it wrong. BTW, this is to be expected from "Instructables". If you check the archives of this and other forum sites, you will find that many of his postings are wrong, and some are dangerous.

ak
 
Thats understandable. I wonder if that wasnt the case maybe thered be some way to turn finish it off into an ohmmeter but unfortunately doesnt work very well...
 
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