Electronic device and method for testing a circuit board

A method for testing a circuit board which comprises a set of input contacts, a set of output contacts and an electrical circuit connected between the input contacts and the output contacts, comprising:

• a) applying a predetermined test signal, configured as at least one of a pulsed signal, an alternating current signal with a predetermined frequency and an alternating current signal with a sequence of predetermined frequencies, to the set of input contacts,
• b) tapping off a response signal at the set of output contacts,
• c) analyzing the response signal,
• wherein a controller performs said applying, said tapping and said analyzing at least once during operation of an electronic device which comprises the circuit board,
• d) comparing a result of the signal analysis with an expected value, and
• e) if said comparing produces no match between the signal analysis result and the expected value, preventing, at least partially, further operation of at least part of the electronic device,
• wherein the electrical circuit is configured as a passive network having a characteristic transfer function and comprises at least one capacitive element comprising a conductor surface which, in the installed condition, forms a capacitor with a corresponding, device-side conductor surface which, in the installed condition, is connected via a contact element to the electrical circuit, whereby the capacitance of the capacitive element in the installed condition differs from the capacitance of the capacitive element in the uninstalled condition.