How to Design an Air Core Inductor

An air core coil inductor is made by winding several turns of enameled wire around a none ferromagnetic material core (like plastic, ceramic, or other non-magnetic forms, as well as only with air inside the windings).

These coils have lower inductance compared to the ferromagnetic core coils. Despite of this characteristic, air core coil inductors are often used at high frequencies because they are free from energy losses called core losses that occur in ferromagnetic cores (which increase with frequency).

In air core coils with winding not rigidly supported on a form (core), a side effect called 'microphony' may occur. 'Microphony' refers to the mechanical vibration of the windings which in-turn causes variation in the coil inductance.

The major advantages of air core coils are:

1. The inductance is independent of the electrical current through the coil since there is no ferromagnetic core to get saturated as the current increases.

2. There is no iron loss as in case of ferromagnetic cores, thus giving a better Q Factor and low distortion with increased frequency.

3. They can be operated at high frequencies (upto 1 Ghz).

The inductance of an air core coil inductor can be calculated using the equation shown in the above figure.

here,

    L = Inductance (in uH)
    a = Diameter of the coil (in Inches)
    b = Length of the coil (in Inches)
    c = Diameter of the winding wire (in Inches)
    n = Total turns of wire

Note: The formula is valid only if the value of b is greater than 0.4a.

How a software interacts with hardware? - Basics of Computer Electronics

In modern computer programming, every software is written using a software programming language. This text program (called high level language) is then converted into runnable (executable - low level language) format by special softwares called compilers(or interpreters). The specialty of this low level language is that it could be understood by a hardware (precisely a microprocessor - a type of electronic component which can perform electronic operation based on software codes). The microprocessor reads the program (low level) and perform the corresponding action.

Now the microprocessor understands a particular code by reading (actually, its sensing electronically) the bits in the particular code. For example if a microprocessor is made in such a way that it will make its 5th pin to +5 voltage level when it reads a bit sequence 0010011, then the processor perform the action whenever it reads a 0010011 in the code. In this way the actions to be performed by a particular microprocessor and the corresponding bit sequence is defined at the time the microprocessor is manufactured. As you know, in a computer system, the microprocessor is the brain, so all the operations are carried out by it.

The computer peripherals (like mouse, keyboard etc) are identified by using configuration files called drivers. These files contain the information that is to be used for interacting with the hardware. The Operating System (windows, linux etc) controls and monitors the peripheral (hardware) control and management.