Uni-t 139S bug

When you feed the multimeter a 50% pwm square wave with offset greater than the amplitude, if you go to mV scale and switch from DC to AC several times, the second time on AC it will measure 0 mV. If the signal has the offset less than the amplitude (for example 0.2V as shown in video), you won't get this weird behavior.
More about this dmm here: https://www.eevblog.com/forum/testgear/ut139e-and-ut139s-digital-multimeters-no-discussion/

Видео Uni-t 139S bug канала paulbt