You will need

- Active LC meter or multimeter with a function for measuring inductance

Instruction

1

Get an LC meter. In most cases, they are similar to conventional multimeters. There are also multimeters with a function for measuring inductance - such a device you will also work. Any of these devices can be purchased in specialized shops selling electronic components.

2

Power off the fee, which is a coil. If necessary, discharge the capacitors on the Board. Wipaire coil,

**the inductance of**which you want to measure from the circuit Board (if this is not done, the measurement will be made visible error), and then connect to the input sockets of the device (to which it is specified in his instructions). Switch off the device at the exact limit, usually designated as "2 mH". If**the inductance**of the coil is less than two, MH, it will be defined and shown on the display, after which the measurement can be considered complete. If it is greater than this value, the meter will show overload - in the senior category will appear one and in the other spaces.3

If the meter showed overload, switch off the device at the next, coarser limit - "20 mH. Note that the decimal point on the display shifted to change the scale. If the measurement this time is not successful, continue to shift the limits towards more rough as long as the overload disappears. Then read the result. Looking then to the switch, you will know in what units the result is expressed in Henry's or the MH.

4

Disconnect the coil from the input jacks of the device, and then solder back to Board.

5

If the instrument shows zero even at the exact limit, the coil either has a very small

**inductance**, or contains the short-circuited coils. If even at the coarsest limit is indicated overload, the coil is either broken or has too much**inductance**, the measurement of which the device is not designed.Note

Never connect the LC-meter to the circuit, under voltage.

Useful advice

Some LC-meters have a special knob to adjust. Check the instructions for the instrument, how to use it. Without adjusting the readings will be inaccurate.

# Advice 2: How to measure inductance

To measure

**the inductance**of the coil, use an ammeter, voltmeter and frequency counter (if not known, the frequency of the AC source, then take readings and calculate the**inductance**. In the case of the solenoid (coil whose length is much greater its diameter) to determine the inductance required to measure the length of the solenoid, the area of its cross section and number of turns of the conductor.You will need

- an inductor tester

Instruction

1

Measurement of inductance by the method of voltmeter-ammeter.

To find the

To find the

**inductance**of a conductor by this method, use the AC source with a known frequency. If the frequency is not known, measure its customera joining it to the source. Connect to the power supply coil,**the inductance**of which is measured. Then in series turn on the ammeter, and to the ends of the coil in parallel is a voltmeter. Passing the current through the coil, clear the readings. Accordingly, the current in amperes and voltage in volts.2

According to this data, calculate the value of inductance of the coil. For this value of the voltage divide successively by 2, the number 3.14, the values of current frequency and current. The result is the value of inductance for the coil in Henry (H). Important: the coil connect only to AC power source. The resistance of the conductor used in the coil should be negligible.

3

The measurement of the inductance of the solenoid.

To measure inductance of the solenoid take a ruler or other instrument for determining lengths and distances, and determine the length and diameter of solenoid in meters. Then count the number of its coils.

To measure inductance of the solenoid take a ruler or other instrument for determining lengths and distances, and determine the length and diameter of solenoid in meters. Then count the number of its coils.

4

Then find

**the inductance**of the solenoid. To do this, take the number of turns in the second degree, the result and multiply by 3.14, the diameter of the second degree, and divide the result by 4. The number you divide by the length of the solenoid and multiply by 0,0000012566 (1,2566*10-6). This will be the value of the inductance of the solenoid.5

If possible, to determine the inductance of this conductor use a special device. It is based on scheme, called bridge AC.

# Advice 3: How to determine the inductance of the coil

The inductance of the coil can be measured directly or indirectly. In the first case, you will need active or bridge device, and the second will have to use the generator, voltmeter and milliammeter, and then to carry out a series of calculations.

You will need

- - active or bridge meter inductance;
- - generator of sinusoidal voltage;
- - voltmeter and milliammeter AC;
- - frequency;
- - scientific calculator.

Instruction

1

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.

2

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.

3

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.

4

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.

5

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.

6

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).

Note

Do not touch the elements of the measurement circuit when it is energized.