It is possible to learn by yourself, using Ohm's law and using a special formula. The great physicist Georg Ohm is the author of the famous law which is:"the current in the circuit is directly proportional to voltage and inversely proportional to the electrical resistance of this portion of the circuit and
written by the formula:I=U/R
where: I - current(A);
U - voltage (V);
R - resistance (Ohms).
It is significant that Ohm's law is fundamentalization. Onpremises to any system in which the action is streams of particles or fields that overcome the resistance. It is applicable for the calculation of pneumatic, hydraulic, magnetic, light, electric and heat flows.
Georg Ohm also found a formula for calculating power in an electrical circuit:
where P ispower(W);
U – voltage (V);
I – amperage (A).
Based on this formula, it is easy to find the voltage. To do this:- take the value of the power P;
- divide it by the current value of I; the Value of power can be identified in the user manual (passport) electrical device that you used. If it is enabled multiple devices, determine their total capacity, which can be calculate by adding together the capacity of all the existing devices:
The value of the current is from the user guide of the appliance or by measuring it directly in the network with the help of the ammeter. Measurement of current in single-phase and three-phase circuit is the same.
To measure current: (A) take the ammeter;
B) turn it into one of the phases of the electrical network;
C) write down the readings.
Now substitute the found values of power and current in the formula:
U = P/I, gder – power (watts), I is amperage (A).
Substituting in the formula numerical values, find the voltage U (In).