uninterrupted power supply implementation

Thread Starter

newbie15yrsold

Joined Jul 16, 2022
2
Hello,
We are students and were tasked to build a project wherein there will be an automatic power switch for emergency. The concern is that there must be no interruptions during the switching which in this case is said to be 1 sec(See the picture below). We are looking for very simple solutions but this is not our forte and we need professionals for help. Is there a way to make adjustments on this module if there is to make it uninterruptible? The load is the arduino uno that needs 12volts since it has devices connected to it too that consumes power on it. I only have 2 capacitor 4700uF and 25v/50v and 220, 10k, 100k ohms resistors. We are new to this kind of things so please if you have any idea please share with us thank you.^^yx850.jpg
 

MrChips

Joined Oct 2, 2009
26,791
Welcome to AAC!

This is a common request.
A device is usually powered from a power supply connected to AC mains with battery backup power.

The simple solution takes two diodes. Here is an example.


1658027647318.png

BAT1 and V2 can be whatever voltage is required by the load. The operation is simple. The higher of the two voltage sources will supply current to the load. When one supply drops out the other takes over automatically without interruption. The diodes prevent one supply from driving current into the other supply. In digital logic design this is called an OR gate.
 

MisterBill2

Joined Jan 23, 2018
12,722
The diode "OR" gate, as described, is the simple and effective way to avoid any interruption at all. It is very effective for DC systems. For AC systems the solution is more complex. It is occasionally called an "on line" system, which has an inverter constantly powering the load, and a similar DIODE "OR"passing power either from a rectified mains supply or batteries, so that if the mains supply fails the battery supplies the power immediately.
Some versions have had one transformer excited by both the mains and the inverter, with levels adjusted so that the inverter excitation is not normally providing the power. This scheme is more efficient but more complex.
 

Thread Starter

newbie15yrsold

Joined Jul 16, 2022
2
Welcome to AAC!

This is a common request.
A device is usually powered from a power supply connected to AC mains with battery backup power.

The simple solution takes two diodes. Here is an example.


View attachment 271606

BAT1 and V2 can be whatever voltage is required by the load. The operation is simple. The higher of the two voltage sources will supply current to the load. When one supply drops out the other takes over automatically without interruption. The diodes prevent one supply from driving current into the other supply. In digital logic design this is called an OR gate.
Thank you very much, I can now understand how I should do it. It really is a big help.
 
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