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 make an inductor

Coil

**inductance**is a rolled into a spiral conductor, storing magnetic energy in a magnetic field. Without this element it is impossible to build neither a radio transmitter nor a radio receiver, for use of the device wired connection. And TV, to which many of us are so accustomed to, without coil**inductance**unthinkable.You will need

- Wires of various sections, paper, glue, plastic cylinder, knife, scissors

Instruction

1

The basis of the coil

**inductance**is a conductor. Around the conductor passing through it a current the magnetic field is always present. The strength of this field depends on the strength of current in the conductor. Another way to strengthen the magnetic field to collapse the conductor into a spiral. This is nothing more than a coil**of inductance**. The smaller the coil diameter, the more turns the stronger the magnetic field generated by the coil. Hams usually wound these coils on their own.2

Inductance is the ability of the coil to create a magnetic field. Inductance is measured in Henry (H).

3

Coil

**inductance**is not produced in the form of standard parts with standard specifications, as calculated and manufactured for each specific device separately. Therefore, in the manufacture of coil you will need to first consider the characteristics of input and output signals of your radio.4

For VHF and short-wave oscillatory circuits are made coils with few turns of thick wire. Some of these coils don't have a frame.

5

For transmission and reception of radio signals at medium and long wavelengths are used multiturn coil (single-layer and multi-layer). To make the frame for these coils you will need paper or plastic.

6

The number of turns of the coil when you configure the radios and other equipment will have to pick up experimentally, changing the inductance of the coil. You can do it otmuchivaniem and Domitiana of turns of the coil, but this method is not quite useful in practice. This files most often placed inside the coil pull out a core of special magnetic material. This can be alsever (an alloy of aluminum, iron and silicon).

7

Magnetic cores concentrate the magnetic field of the coil, thus increase its inductance. With this you can reduce the number of turns of the coil, which leads to the decrease of its sizes and dimensions disturbed.

# Advice 3 : 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.