AEMC MR527 [1200.85] AC/DC Current Probe, 100AAC, 150ADC, 10mV/A and 1000AAC, 1400ADC, 1mV/A, BNC Output. The AEMC MR527 is a hall effect current probe with 2 ranges designed for oscilloscopes, waveform displaying instruments, and other frequency sensitive displaying instruments with BNC inputs. The probe has a 6.5 ft (2m) lead terminated by a BNC connector and can measure up to 1000AAC and 1400ADC. The MR527 probe is powered by a 9V battery or by a standard 5V external power supply via a micro-USB connector (not supplied).