I want to protect from short circuit by using a miniature circuit breaker. But this has to be manually turn ON, when ever it is turned OFF. So I was thinking to make a electronic circuit breaker which cuts the power supply when ever there is a short circuit. And able to read the state of the circuit and turn it back ON using a micro controller. I am using 230V AC. And a Max Current of 16A.
Something like this should work:
The shunt resistor is 1 ohm, 1 A will cause 1 V voltage drop. set the maximum current allowed via non-inverting pin of the op amp. If voltage drop on the shunt is bigger than the reference voltage, op amp will drag it's output to negative rail and vice versa.
we configured the op amp as comparator, so the output is either high or low. connect the output of the op amp using a resistor to the digitalRead of MCU. in the program if the current is higher than what you set
(digitalRead == LOW;), energize the relay and "break the circuit". you should put some delay in there too, otherwise it will keep connecting and disconnecting the relay. or you can manually connect the relay in case short circuit happened.
It's literally just four components, using miniature relays and SMD op amp/resistors it shouldn't be bigger than 4-5 centimeter.
For AC current sensing you can use the same circuit except instead of using a shunt resistor to sense the current. Use an hall effect sensor and feed it's output to the op amp inverting pin: