ELECTROCARIAN

2.1 Dielectric constant 2.1.1 Definition The Dielectric constant (or relative permittivity) is an intrinsic property of dielectric material. Under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. It is the ratio of the amount of stored electrical energy when a potential is applied, relative to the permittivity of a vacuum. The relative static permittivity is the same as the relative permittivity evaluated for a frequency of zero. The relative permittivity describes the ease by which a dielectric medium may be polarized. The capacitance of a capacitor is proportional to ε r . The dielectric constant (relative static permittivity) is represented as ε r or sometimes κ or K. It is defined as ε r = ε/ε 0 Where ε is the static permittivity of the material, and ε 0 is the electric permittivity of the free space(which is equal to 8.854*10 -12  F/m) The relative permittivity is complex  and frequency dependent, which gives the static relati

Timer operation using 555 IC 10.1. Introduction One of the most versatile linear integrated circuits is the 555 timer. The 555 is a monolithic timing circuit that can produce accurate and highly stable time delays or oscillation. The timer basically operates in one of the two modes: either as a mono-stable multivibrator or an astable multivibrator. The device is available as an 8-pin metal can, an 8-pin mini DIP or a 14-pin DIP. FEATURES: 1. It operates on +5V to +18V supply voltage in both free running and monostable modes 2. It has an adjustable duty cycle; timing is from microsecond through hours. 3. It has a high current output; it can source or sink 200mA 4. The output can drive TTL and has a temperature stability of 50 parts per million per degree Celsius change in temperature. 5. Like general-purpose op-amps, the 555 timer is reliable ,easy to use and low cost. 10.2 . Pin Descriptions The 555 timer IC can be used as a monostable multivibrator, an astable multivib