UT204 is able to measure DC current and also True RMS
Clamp multimeter UT204 measures reliably even in real conditions of nowadays mains supplies and for an affordable price moreover.
UT204 from company UNI-Trend is a near relative to the UT203. multimeter. Already UT203 provides a lot of user comfort and a very pleasant feature – measuring of a DC current without interrupting a measured circuit. However UT204 is different from its “weaker” brother in one essential thing – it enable measuring of a true RMS value of alternating signals (TRMS).
As we know, usual multimeters usually deploy a simple rectifier and an RC cell and they´re calibrated to show an effective value of AC voltage – supposing an ideally sinusoidal shape of a measured variable. In many cases, a non-TRMS multimeter is fully sufficient, but still more frequently we meet devices, which by their power consumption significantly deform originally sinusoidal shape of a mains line voltage. A vast majority of new devices is equipped with switch-mode power supplies deforming a sinusoid, as they draw current for charging of input capacitors mainly on a top of a sinusoid. This situation is partially better at power supplies with a power factor correction (PFC), but even in these cases it´s never an ideal load. At any difference from an ideal sinusoid the accuracy of a common meter significantly drops down and the error can exceed tens of percents. Similar situation is also at various DC/AC inverters (for example 12VDC/230VAC), whose output is usually only an approximated sinus.