Method for qualifying joints and contacts of electric circuits

A method of qualifying an electric circuit having at least one joint or contact comprising the steps of:

• providing a reference function of thermoelectric voltage versus time of a faultless electric circuit,
• heating the electric circuit by At least one measuring electric impulse that is between 1-14 V and the lengths of the measuring electric impulses are between 5-30 ms,
• acquiring the thermoelectric-voltage-versus-time data of the electric circuit,
• comparing the acquired thermoelectric-voltage-versus-time data to the reference function,
• qualifying the electric circuit based on the differences between the acquired data and the reference function.

A post-manufacture method for localizing a weak or bad contacting joint or contact of a completed electric circuit, the method comprising the steps of:

• providing reference functions of thermoelectric voltage versus time of different possible locations of the weak or bad contacting joint or contact of the electric circuit subsequent to manufacture of the completed circuit,
• heating the electric circuit by at least one measuring electric impulse,
• acquiring thermoelectric-voltage-versus-time data of the electric circuit,
• comparing the acquired thermoelectric-voltage-versus-time data to the reference functions,
• localizing the weak or bad contacting joint or contact of the electric circuit in accordance with the similarities between the acquired data and reference functions.

A method of localizing a weak or bad contacting joint or contact of an electrical circuit, the method comprising the steps of:

• providing reference functions of thermoelectric voltage versus time of different possible locations of the weak or bad contacting joint or contact of the electric circuit,
• heating the electric circuit by at least one measuring electric impulse that is between 1-14 V and the length of the at least one measuring electric impulse is between 5-30 ms,
• acquiring the thermoelectric-voltage-versus-time date of the electric circuit,
• comparing the acquired thermoelectric-voltage-versus-time data to the reference functions,
• localizing the weak or bad contacting joint or contact of the electric circuit in accordance with the similarities between the acquired data and reference functions.