The purpose of this research is to study, design and build over current protection circuits for low voltage AC supply for electrical and electronic circuit experiments in laboratories to prevent damage to circuits and equipment. The use of transformers as current detectors in this research focuses on 3 issues: 1. Circuit design and testing 2. Determination of voltage drop and power loss at current sensing transformer 3. Finding the efficiency of the designed circuit. This test will be performed 5 times to ensure the accuracy of the designed circuit. The research results showed that the designed circuit can cut the circuit efficiently and with precision, the designed circuit has an error of not more than 1%, can cut off the circuit when an over current occurs and prevent short-circuit and reduce the rate of damage of the device
