Abstract: An electronic device offering protection against connection of a direct current power supply unit with reverse polarity includes a branch disposed between two potential lines and including a reverse biased diode and a first component sensitive to a flow of current. A first switch is disposed on the downstream side of this branch, on one of the potential lines. A control circuit has two terminals receiving a control signal and, connected in series between those terminals, a second switch and a second component sensitive to a flow of current. The first switch, normally open, is closed by the second sensitive element if the latter detects a flow of current. The second switch, normally closed, is opened by the first sensitive component if the latter detects a flow of current.