For a complete diagnosis of the vehicle's electrical devices it is necessary to measure the amperage in addition to the voltage. Current can be measured by connecting an ammeter in the gap of an electrical circuit, but the measurement can also be done without a direct connection to the wire. A current clamp probe is a special device which measures the magnetic field created by the current and converts it to a voltage. For this purpose, it is enough by putting a special clamp around the wire. The current waveform allows you to find sources of current leaks, sparking problems with poor contact, to measure large starter or alternator currents, and to get a timing signal from the injectors and ignition coils of the car.