# Over voltage and reverse polarity protection

I was trying to make an over voltage and reverse polarity protection circuit and create a PCB that I can easily use in some of my projects.

My level of electronics it's not so good, and that's why I'm here.

I thought one circuit, but as long as I know it's not so good:

simulate this circuit – Schematic created using CircuitLab

There's a bunch of circuits arround the internet that involves transistors, but I don't know which one I would pick (or even an IC, as it was discussed previously here, but I couldn't understand which configuration should I use).

Here's my requirements:

• It should output around 5V (if the input it's too low it can output less voltage, but if it's greater it should be limited). I want to use it with 74LS ICs, so the input voltage should be 5V, but it can go from 4.75V to 5.25V. The current used it's, at most, 1.5A.
• The input voltage can go from +40V to -40V.
• I'm using a workbench power supply, so no need to over current protection (it's already integrated).
• It should be as simple as possible (~5 components). I don't want to solder >25 components.
• I don't care if something blow up. As long as the external circuit stays safe, it's OK for me.

Is there an IC or circuit that suits my needs?

Please go nice on me, this isn't my specialty. Thanks!

• Just zenner 5.6V 10W. Set proper current limit, like 1A. Jan 16, 2021 at 19:28
• @user263983 OK, or even the fuse solution seems OK to me (just in case). Can you explain me why 5.6V and not 5.1V? 5.6 it's above the maximum voltage. There's one problem with the diode, and it's that there's a small current in reverse voltage, and maybe that current can lead to the destruction of some ICs. Jan 16, 2021 at 19:30