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5 minutes self-healing protection against reverse polarity


During testing their electronic products, connecting the charger to an acidic car battery, inadvertently or in a hurry when connecting power, a polarity reversal occurs, which in some cases can adversely affect the tested device, battery. (Hindyk microcontrollers, explosion of capacitors, etc.)

To protect their circuits and memory from destructive polarity reversal, many include a diode in the circuit (conducts electricity in one direction), to prevent the current from flowing in the opposite direction, thereby eliminating the harm to the electronic components of your device. But the problem with this approach is that this circuit will not work until you change the polarity, which is sometimes not possible (during testing).

In order not to be soared with polarity reversal, I offer a simple little circuit for testing and connecting your electronic masterpieces and batteries auto. One has only to include in the chain not a big superstructure. You no longer have to worry about the polarity reversal and search for a DC adapter, which is somewhere there at the right time ...
5 minutes self-healing protection against reverse polarity

This circuit uses a rectifier bridge that is built into all power adapters. Just plug in the first power supply you get in the circuit (without worrying about polarity). Connect direct or alternating current, this is not at all critical for this circuit, plus or minus is also not important.

The only drawback of the circuit is that the rectifier bridge eats up some voltage, you will need to take this fact into account when testing and connecting the battery, (add voltage to the memory), if this is critical for you during testing.
You can use a ready-made bridge that meets your needs.

Or make from 4 diodes the power you need




Cheap and cheerful! Good luck
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5 comments
Some manufacturers initially build a diode bridge in their technology. At the same time, they can equip the device with an external source with any overlap, and they will not disdain change. And in automotive technology for life they used one counter diode and a fuse.
Author
A diode bridge for demonstration, and the characteristics are:
Characteristics of the diode UF4007

Maximum DC Reverse Voltage 1000 V
Maximum direct forward current 1 A
Recovery time - 75 ns
Diode Capacitance - 15 pF
Maximum forward voltage 1.7 V
Operating temperature -55 ... + 125 ° С
Case Type - DO-41
Weight - 0.33 g
And once I reversed and burned the projector from my camp movie theater (it’s in my homemade products), and therefore, in order not to step on this “rake” later on, I just stupidly built in a box with a bridge to the D-242 from the middle of the cord .. Here like the author ...
One would be enough. There goes constant from the battery ... But the bridge was ready from some kind of military device. So I hung it ... And it works ... Already there was "sloppiness" again .... And nothing, why.))))

And on the topic ... What he offers is bad due to current restrictions ... I, for example, have ready-made neat bridges from 226's (Diodes on the board are "parallel" located and all this is in a plastic box .) ... But no - there isn’t enough current ... I had to hang the bandura with nuts.))).
And what will stand those in the photo? (I just ask for the characteristics! In the old "hats" diodes, I still understood, but I do not know these at point blank ....)
And anyway ... Since he wants a bridge ... Isn’t it easier to solder the finished chocolate bar ??? Now they are on unthinkable (for reasons of my youth) currents of tens of amperes ...
Or, they have "return" strong ???
And this protective device should look something like this.

This is the easiest and most reliable option. There is no desire to collect, put into the case and publish. I give an idea - bring it to life and show. I will not claim authorship xaxa
Self-healing protection is a slightly different device. And it serves as an electronic fuse. And this is just a diode bridge. And from a polarity reversal it cannot be self-healing protection. It may just be a protection that either breaks the power circuit during a polarity reversal, or switches this power circuit to the correct polarity.

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