The Philips AC millivoltmeter PM 2554 is a sensitive and accurate measuring instrument suitable for floating measurements from 50 µV up to 300 V in the frequency range from 2 Hz up to 12 MHz. The instrument can be powered by mains. By the very great bandwidth and sensitivity the instrument has a width range of applications, e.g. measurements on LF and HF amplifiers, carrier-wave telephony, electro-acoustical as well as for measurements on transducers and measuring-transformers, etc. The d.c. or a.c. output choosen by an internal jumper, makes it possible to employ the instrument as an a.c./d.c. converter or as an a.c. amplifier. The instrument has a great indicating speed, a high temperature stability and is quickly ready for use. The 12 measuring ranges of 1 mV up to 300 V f.s.d. overlap so that a high reading accuracy is obtained. The moving-coil instrument is provided with a mirror scale with the ranges 0-30 and 0-100 as well as dB scale from —20 dB...+ 2 dB (total span —80 dB... + 52 dB). By means of the measuring-probe PM 9336 the input impedance can be changed from 1 MΩ// 30pF except capacity measuring cable (100 pF) into 10 MΩ// 11 pF to permit measurements on very high ohmic circuits.