You will need
- - active or bridge meter inductance;
- - generator of sinusoidal voltage;
- - voltmeter and milliammeter AC;
- - frequency;
- - scientific calculator.
To measure the inductance of the active device, connect the coil and then successively selecting the measurement range switch, select such of them to the result was approximately in the middle of the range. Read the result. If the meter has an analog scale, when reading the results, take into account the price of division, and the coefficient shown next to the corresponding switch position.
On the bridge device after each selector turn the knob balancing of the bridge at any of the end positions, and then rotate it all the way in the opposite direction. Find a range in which the handle is possible to balance the bridge. Having achieved the disappearance of the sound in the speaker or headphones or decreasing readings dial indicator to zero, read the indications on the scale of the regulator (but not the gauge). In this case, as in the previous case, consider the division and the factor that should be multiplied by the range statement.
To measure inductance indirectly assemble the measuring circuit. The AC voltmeter switched to the limit at which the upper boundary of the range corresponds to a voltage of several volts, connect the parallel output of the generator. There connect and a frequency counter. Also in parallel, they connect the series circuit consisting of the test inductors as well as milliamperemeter AC. Both devices should show the current, not the amplitude value measured value, and can be calculated for sinusoidal oscillations.
The generator will enable the generation of the voltage sine wave. Ensure that the voltmeter showed about two volts. Increase the frequency until then, until the readings on the milliammeter begins to decrease. Make sure that they reduce to about half the original value. Select frequency limit corresponding to the measured frequency. Read the testimony of all three devices, and then disconnect the generator and disassemble the measuring circuit.
Put readings in SI units. Divide the voltage across the current. Will the inductive reactance of the coil at the frequency at which the measurement was carried out. It will be expressed in ohms.
Calculate the inductance according to the formula: L=X/(2πF), where L is the frequency, G (Henry), X is the inductive reactance in Ohms, F is frequency, Hz. If necessary, move the result of the calculation in derived units (e.g., MH, microgenre).
Do not touch the elements of the measurement circuit when it is energized.