In an embodiment, a device comprises a circuit with at least one circuit element; measurement circuitry capable to test a state of the at least one circuit element during an operation of the circuit, the measurement circuitry comprising a first terminal configured to be coupled to a first node of the circuit via a first capacitor, a second terminal configured to be coupled to a second node of the circuit, wherein the measurement circuitry is configured to determine in situ an operating state of the at least one circuit element based on signals applied by the measurement circuitry to the circuit during the operation of the circuit.