This is an inexpensive analog panel meter useful for 115V circuits. I built mine into a wall power supply. After the block has been powered on for a while, the counter will no longer return to zero. . The zeroing screw doesn't seem to have enough authority to do this. It's about 2.5V or so when not powered. However, the meter still reads well within its stated accuracy - apply 122v, read 125v, apply 130v, read 130v - so I really have nothing to complain about. Dampening effect in the dial…