Guide

1

matter what parameters are given in the problem, move them to the SI system.

2

If the condition given load resistance and released her power, guided by the following considerations: R = U / I, where R - resistance, ohms, U - voltage, V, I - current, A.P = UI, where P - power, W, U -

**drop****voltage**, B, I - current, A.Otsyuda follows that P = I ^ 2 * R, ie, I ^ 2 = P/ R, or I = sqrt (P / R).Consequently, U = R (sqrt (P / R)) or, after simplification of the expression, U = sqrt (P) * sqrt (R), where U - desired**drop****voltage**load, B, R - resistance,Ohm, P - power watts. 3

much simpler case occurs if found
: U = P / I, where U - required

**voltage drop is necessary, knowing the power and strength of the current.Convert expression is not required, so just use the following formula****drop****voltage**, B, P - power dissipated in the load, W, I - the current passing through the load, and. 4

If you know the load impedance and passing through it current,

**drop****voltage**her as calculated in one action: U = IR, where U - required**drop****voltage**, in, I - current passing through the load, A, R - load impedance, ohms. 5

addition to the above the most frequently encountered problems, there are also other books in which you need to know

**drop****voltage to a length of a homogeneous rod made of a material having a high resistance.To do this, first calculate****drop****voltage**the entire length of the bar (if it is not given in the problem initially).Then, subtract one from the other horizontal coordinates of points,**drop****tension between them to be determined.** 6

voltage over the entire length of the rod to divide its length and then multiply by the calculated length of the segment you, and you get a drop

**voltage between points.Such dividers are encountered in the apparatus with a transformerless power supply and used as network switches****voltage - in this case, the simple design sacrificed efficiency and safety.** 7

completing calculations, if necessary, turn the result into convenient for presentation units: volts, millivolts, kilovolt, etc.