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polarity protection with diode between vcc and gnd

Kardo22

Mar 7, 2014
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Is it OK to do it like on the picture.
To protect circuit from power connector inserted the wrong way.
I'm thinking of this solution a voltage drop wouldn't be good.
Power is supplied by a common benchtop DC power supply, current limited to 200mA.
 

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Harald Kapp

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Nov 17, 2011
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It is o.k. if the diode can withstand the power dissipation produced by the current (approx. 140 mA @ 200 mA).
An even better protection scheme would include a fuse between the diode and the positive input. That way the fuse will blow if wrong polarity is applied, thereby protectiong the circuit completely.
 

duke37

Jan 9, 2011
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Battery driven equipment can often run on lower than the nominal voltage. I would try a diode in series with the supply and see it it works satisfactorily.

There is a cunning circuit using a FET which is only turned on with the right polarity. I have never tried this.
 

duke37

Jan 9, 2011
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I have had a fooster and found the circuit I was after. The diode is within the FET.polarityprotecct001.jpg
 

HellasTechn

Apr 14, 2013
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Is it OK to do it like on the picture.
To protect circuit from power connector inserted the wrong way.
I'm thinking of this solution a voltage drop wouldn't be good.
Power is supplied by a common benchtop DC power supply, current limited to 200mA.
Dont use this topology because you risk shorting and burning your psu if inserted the wrong way.
Better use a fuse in serries as suggested before or place the diode on one of the rails with correct direction.
as for the above circuit i have also never used it.
 

HellasTechn

Apr 14, 2013
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if you use the fuse make sure you connect it like this :
 

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