Re: reverse polarity protection (ubitx.net)

Jerry Gaffke
 

Here's an old discussion about using a PFET for reverse polarity protection.
    https://groups.io/g/BITX20/message/35434
Useful, but how it works is confusing enough that it is often implemented incorrectly.
Which makes it dangerous, especially for the hobbyist.

For the uBitx, I prefer the solution of post 56141

Jerry, KE7ER


On Wed, Aug 8, 2018 at 10:20 AM, Mvs Sarma wrote:
Very Nice concept to use a pFET, mike Yancey.
 
 I suppose, most power fets would have a reverse diode across Drain and Source.
 what happens of some one connects DC input in reverse,
 The diode takes on and sends the reverse voltage to the load not caring "gate control"
.
Please analyse and let us find a way.
 
. . .

 


On Wed, Aug 8, 2018 at 8:15 PM Mike Yancey <mikeyancey@...> wrote:

I usually prefer the P-FET solution - prices have come down for these, around a buck per P-FET.
And not only the price, but more & more P-FETs with very low V-forward drop.

No fuse to replace (if you're 'wrong') and nearly no voltage drop (when correctly connected).

Also: consider Power Poles. Using Power Poles makes it *very* hard to mal-connect.

Mike Yancey, KM5Z
Dallas, Texas, USA

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