In alternating current, voltage = current × impedance. Here, voltage, current and impedance are all in phase. Mathematical complex numbers are widely used in electrotechnics, and it is convenient to calculate voltage, current and impedance with complex numbers.

Formula:

Ohm's law I=U/R, current unit A, voltage unit V and resistance unit ω.

Electric power refers to the work done per unit time, with the symbol P, P = W/T, where W is the work and the unit is J; The unit of time is S. Electric power can also be expressed as p = I 2 * r (the square of current I divided by resistance R) = U 2/R (the square of voltage U divided by resistance).

Specific relationship:

First, if the same circuit has only one resistor, it has nothing to do with voltage. The voltage is only artificially applied across the resistor, regardless of the size of the resistor. You can add as much as you want.

Second, if there are other appliances besides this resistor in the same circuit, it will affect the voltage. However, its influence only affects the voltage distribution on various electrical appliances. That is, the greater the resistance, the greater the power supply voltage distributed by the resistance itself, and the smaller the voltage at both ends of other appliances.

Third, in essence, resistance cannot hinder voltage. Resistance blocks the current. Can be analyzed from a microscopic point of view. Current is a carrier one by one, and they pass through the resistance together, just as the uneven road blocks them. The proportion of the number of carriers blocked by resistance is certain, so if you want to increase the number of carriers, you must increase the voltage to increase the number of carriers. However, the proportion of resistance has not changed, and the proportion is still so large.