| 摘要 |
PROBLEM TO BE SOLVED: To reduce the leak amount of common mode voltage from the side of primary circuit to the side of secondary circuit by forming a center tap on the secondary winding wire side of a transformer for insulation and connecting this center tap to a ground on the side of secondary circuit. SOLUTION: A transformer 11 mutually insulates the primary circuit on the side of a primary winding wire 11a and the secondary circuit on the side of a secondary winding wire 11b and transmits a signal inputted to the primary winding wire 11a toward the secondary winding wire 11b. Both the winding wires 11a and 11b respectively have center taps 11c and 11d, the center tap 11c is connected to the output part of an operational amplifier 21 and the center tap 11d is grounded to a ground G2 on the side of secondary circuit. The common mode voltage leaked to the side of the secondary winding wire 11c flows through the center tap 11d into the ground G2 of much lower impedance. In such a case, since the impedance of the center tap 11d is extremely low, no voltage is generated so that the common mode is not inputted to the resistor side as a result. |
