14/42-volt automotive circuit tester

A portable hand-held automotive circuit tester for detecting voltages in plural different voltage ranges corresponding respectively to plural different-voltage automotive electrical systems, the tester comprising:

• input means adapted to be coupled to the circuit being tested for producing an input signal,
• reference means for producing a plurality of reference signals arranged in sets corresponding respectively to the plural different voltage ranges with each set incrementally graduated from a low amplitude to a high amplitude;
• comparison means coupled to the input means and to the reference means for comparing the input signal to each of the reference signals, and
• plural groups of indicators respectively corresponding to the set of reference signals and coupled to the comparison means so that only one group of indicators will be operable depending on the voltage of the automotive electrical system being tested,
• the comparison means being responsive to the input signal for energizing the indicator corresponding to the highest reference level which the input signal equals or exceeds.

A method of testing plural different-voltage automotive electrical systems comprising:

• providing a single portable hand-held tester capable of detecting voltage levels in ranges associated respectively with the different-voltage automotive electrical systems and having different groups of indicators corresponding respectively to the voltage level ranges,
• using the tester to acquire input signals from each of the plural different-voltage automotive electrical systems,
• comparing each input signal with a plurality of reference voltage levels arranged in sets corresponding to the different voltage level ranges with each set incrementally graduated from a low amplitude to a high amplitude, and
• indicating the voltage level of each input signal by activating a corresponding indicator in the group of indicators associated with the voltage of the electrical system from which the input signal is acquired.