An easy construction to protect our devices from short circuit damage. Here I use a 12 V 16 A relay for 12 V input voltage.
You can also use a 5 V or 24 V relay if the input voltage is 5 or 24 V.The max current of the relay depends on the external electric load we connect to the output. Don' use Pb batteries as a supply. It is dangerous to burn the device. I also suggest to connect an external fuse before the device in case that something went wrong to protect the pwer supply (if it doesn' t have an internal automatic cut switch).
You can watch the construction and the use here: