- Published in issue 10/1993 on page 22
Fuzzy logic multimeter - 2:
There is little to say about the true r.m.s. converter. The circuit diagram shows a standard application of the AD736JN, connected to a non-critical R-C network, C4-RI5, and three electrolytic capacitors (also uncrttical). C5, C6 and C7, The bandwidth of the true-r.m.s. converter exceeds that of the multimeter IC input by far. In fact, the multimeter Je limits the -1%- bandwidth of the DMM to about 300 Hz. Keep this in mind when measuring signals with a lot of dtstortion [i.e. containing many higher harrnonics), because for the measurement to be accurate. the strongest harmorucs have to fall within the 300- Hz bandwidth of the DMM.