Abstract: A multimeter has a housing with at least three input connections, configured as female connectors, for connecting to two measurement lines. When a measurement variable is changed, it is possible to connect at least one of the measurement lines to another input connection. The multimeter has a measurement-range switch which can be moved to a switching position associated with the selected measurement variables, and a mechanical blocking apparatus coupled to the switch. The blocking apparatus allows specific input connections to be blocked such that contact can be made only with the input connections which have an associated measurement variable which corresponds to the measurement variable set by the switch. The blocking apparatus is formed as a pivotable angle lever, and the switch moves end regions of strip-shaped angle limbs of the angle lever to a position aligned with the input connections to be blocked.