Ie? You do not know how to read the indication of such a meter? It is quite simple. The whole fun probably comes down to the c meter constants. It is calculated simply, namely for the ammeter and voltmeter you read the set range (e.g. 1 or 3A or 100 or 300V) and the number of divisions on the scale, e.g. 100. In the first case, the ammeter constant c = 1/100 or 3/100 which gives 1 / 100A for each indicated division on the scale or 3 / 100A / div, similarly voltmeter -> 1V / div or 3V / div. If the voltmeter with cv = 3 shows on the scale 20V, the voltage is actually 60V. With a wattmeter it is only so much more interesting that the current and voltage settings are taken into account at the same time. For example, if the wattmeter is set to 100V and 10A and there are 100 divisions on the scale, then the wattmeter constant cw is (U * I) / number of divisions, i.e. (100 * 10) / 100 which gives cw = 10, so if the wattmeter shows 15 plots, in fact, the power is 150W.
