Patent ID: 7835123

Claim:
An electrical and electronic system comprising: an ECU; a power supply circuit that is disposed in the ECU; a first power supply line that is disposed in the ECU and extends from the power supply circuit; first electrical equipment that is disposed at an outside of the ECU, and has one terminal connected to the ground and the other terminal connected to the first power supply line; a first electronic element that is disposed in the ECU and connected to the first power supply line; a noise protection line that is disposed in the ECU and connected to a first element line at one end thereof and to the ground at the other end thereof, the first element line being a part of the first power supply line and connecting the other terminal of the first electrical equipment and the first electronic element; a switching element that is disposed in the ECU and has a first terminal connected to a side of the first element line and a second terminal connected to a side of the ground so that the switching element is connected to the noise protection line in series; and a voltage detector that is disposed in the ECU, detects a voltage value of the first terminal of the switching element and turns on the switching element when the detected voltage value reaches a predetermined value.