AEMC Model 5231 and 5233 TRMS digital multimeters have a nonelectrical contact testing (NCV) function for detecting live electrical circuits. Both models provide a volt, ohm, continuity and diode function. The 5233 also has a capacitance, frequency, duty cycle and ammeter function. They both include an AC voltmeter function with low input impedance that is capable of finding ghost voltages by adding a burden to the circuit. The rotary function switch provides two off positions (off and off NCV). While in the off NCV position, the display will turn red if placed close to a live cable.