Method for detecting a defective amplifier in an analog signal conditioning device of a switch

A method is disclosed for detecting a defective amplifier. The device includes an electronic tripping unit which respectively carries out a check in order to determine whether the energy through the switch satisfies a condition and trips the switch if the condition has been satisfied; and an analog/digital converter respectively outputting the two differently amplified analog signals as digital values. In an embodiment of the method, a decision is made regarding which of the two digital values is used to check the condition. To detect defective amplifiers in the signal conditioning device of tripping units during ongoing operation, a check is carried out to determine whether at least one of the two digital values is in a predefined range; if so, whether the two digital values each belonging to the same time are in a predefined tolerance range. A fault is signaled if this is not the case.