Passive electronics elements are which take energy from sources and either convert in into another form or store it in the form electric or magnetic field. Resistors , inductors , capacitors are passive electronics components.
Resistance : The resistors are mainly used for controlling the flow of current and providing desired amounts of voltages.All electrical devices that consume energy must have a resistor (also called a resistance) in their circuit model. The power rating of a resistor is given as the maximum wattage it can dissipate without excessive overheating. Thus in order to increase the life of resistance , they must operated at less than rated values. The smaller value of temperature coefficient means a higher thermal stability of a resistor.
Type of resistors :
Linear Resistors - The resistors through which the current is directly proportional to the applied voltage , is called as linear resistor.The value of resistance of this resistors is independent on the applied voltage, temperature,light intensity.
Non-Linear Resistors - The resistors through which the current is not directly proportional to the applied voltage,is called non-linear resistors. The value of resistance of this resistors is dependent on the applied voltage, temperature,light intensity. Examples:- Thermistor, photo-resistor, varistor.
Power in the resistor, given by P = v .i = i2.R = v2. R
Energy is given as the integration of instantaneous power,
Resistance : The resistors are mainly used for controlling the flow of current and providing desired amounts of voltages.All electrical devices that consume energy must have a resistor (also called a resistance) in their circuit model. The power rating of a resistor is given as the maximum wattage it can dissipate without excessive overheating. Thus in order to increase the life of resistance , they must operated at less than rated values. The smaller value of temperature coefficient means a higher thermal stability of a resistor.
Type of resistors :
Linear Resistors - The resistors through which the current is directly proportional to the applied voltage , is called as linear resistor.The value of resistance of this resistors is independent on the applied voltage, temperature,light intensity.
Non-Linear Resistors - The resistors through which the current is not directly proportional to the applied voltage,is called non-linear resistors. The value of resistance of this resistors is dependent on the applied voltage, temperature,light intensity. Examples:- Thermistor, photo-resistor, varistor.
Power in the resistor, given by P = v .i = i2.R = v2. R
Energy is given as the integration of instantaneous power,
Inductor : Inductance is a property of coil which opposes changes in current by storing the energy in the form of magnetic field. Current carrying conductor or coil has magnetic field associated with it. If the current through coil changes, this also changes magnetic flux associated with it. This change in flux induces a voltage in the coil. The polarity of induced voltage is such that it opposes the change in current through coil.This is given as,
V = L. dI/dt
where, V = induced e.m.f
dI/dt = rate of change of current
L = inductance of a coil.
Now, this coil is also known as inductor which manufactured with specific value of inductance. It is also defined as the circuit element that stores energy in a magnetic field is an inductor. With time-variable current, the energy is generally stored during some parts of the cycle and then returned to the source during others. When the inductance is removed from the source, the magnetic field will collapse; in other words, no energy is stored without a connected source. Coils found in electric motors, transformers, and similar devices can be expected to have inductances in their circuit models. Even a set of parallel conductors exhibits inductance that must be considered at high frequencies. In many applications , the inductors are used to minimize alternating current in order to permit flow of direct current therefore the are also known as a choke.They are used in receivers as antenna coil to pick up radio signals. Power and energy relationship is given as,
V = L. dI/dt
where, V = induced e.m.f
dI/dt = rate of change of current
L = inductance of a coil.
Now, this coil is also known as inductor which manufactured with specific value of inductance. It is also defined as the circuit element that stores energy in a magnetic field is an inductor. With time-variable current, the energy is generally stored during some parts of the cycle and then returned to the source during others. When the inductance is removed from the source, the magnetic field will collapse; in other words, no energy is stored without a connected source. Coils found in electric motors, transformers, and similar devices can be expected to have inductances in their circuit models. Even a set of parallel conductors exhibits inductance that must be considered at high frequencies. In many applications , the inductors are used to minimize alternating current in order to permit flow of direct current therefore the are also known as a choke.They are used in receivers as antenna coil to pick up radio signals. Power and energy relationship is given as,
Capacitor : Capacitance is a property which opposes the changes in voltage by storing energy in the form of electrostatic energy. A capacitor is a component manufactured with a specified amount of capacitance. It is used to charge or store energy. It opposes changes in the voltage of circuit to which it is connected. When the voltage is variable over a cycle, energy will be stored during one part of the cycle and
returned in the next. While an inductance cannot retain energy after removal of the source because the
magnetic field collapses, the capacitor retains the charge and the electric field can remain after the
source is removed. This charged condition can remain until a discharge path is provided, at which
time the energy is released. Capacitors are used in starting motors , blocking d.c. current , filtering unwanted signals , tuning , coupling circuits , bypass capacitors in the amplifiers. The capacitors consists of two parallel conducting plates , separated by an insulating medium known as dielectric. The charge on the plates (Q ) is directly proportional to the voltage ( V ) across the plates.
i.e. Q = C.V
Where C is capacitance.
It is fact that any pair of conductors, separated by air or other dielectric forms capacitor. It has low value about 1 to 10pF. It is present between the circuit wiring , metal chassis , adjacent conductors on PCBs. This type capacitance is called as stray capacitance. It's effect is small at low frequency, but it has significant effect at high frequencies. It can minimized by keeping wire length as short as possible.
i.e. Q = C.V
Where C is capacitance.
It is fact that any pair of conductors, separated by air or other dielectric forms capacitor. It has low value about 1 to 10pF. It is present between the circuit wiring , metal chassis , adjacent conductors on PCBs. This type capacitance is called as stray capacitance. It's effect is small at low frequency, but it has significant effect at high frequencies. It can minimized by keeping wire length as short as possible.