you need
  • - Tester;
  • - resistivity table
Guide
1
certain voltage current and resistance.Measure the resistance of the circuit, if it is not known in advance to accede to the tester with the appropriate settings.The device connect parallel conductor open circuit.Reconfigure the tester to measure the strength of the current (ammeter mode).Turn it on in series and measure the current value of the force .
2
Using Ohm's law (force current on the circuit is directly proportional to voltage and inversely proportional to resistance), get the value of the voltage.To do this, multiply the force current resistance of the chain (U = I • R).
3
If there is no instrument to measure resistance, identify the material from which the conductor is made on the circuit and find its resistivity at the appropriate table.Find the length and cross section of the wire.Then voltage is equal to the product of the current resistivity and cross-sectional area of ​​the conductor divided by its length U = I • ρ • S / l.You can check the result of the calculation, by connecting the tester in voltmeter mode in parallel to a portion of the circuit.
4
Definition voltage power unit.Inspect the instrument housing, or study its technical passport.There's sure to be the said power consumed by this device.If such data is not found, measure the power consumed by the consumer investigated in another way.
5
To determine the power, connect the tester in parallel mode, the power meter to a working unit.Its value is displayed the power consumed by the device.Measurements are made in watts.
order to determine the value of the voltage on the device, found the power to divide the power current in amperes (U = P / I).Result is obtained in volts.