What is High Pass RC Filter?

A high pass filter blocks all low frequency signals from DC up to its corner frequency, (¦c) and allows all high frequency signals to pass above this point. A first-order RC high pass filter is constructed as follows:


What is Low Pass RC Filter?

A low pass filter allows all low frequency signals to pass from DC (0Hz) up to its corner frequency, (¦c) and blocks all high frequency signals above this point. A first-order RC low pass filter is constructed as follows: \[A=\frac{Vout}{Vin}=\frac{Xc}{Z}=\frac{Xc}{\sqrt{R^2+Xc^2}}\] \[A=\frac{1}{\sqrt{1^2+(ωRc)^2}}\] `fc=\frac{1}{2\piRC}` or  `ωc=\frac{1}{RC}` \[Af=-3dB=\frac{1}{\sqrt{2}}=0.7071Vin\] Roll -off = -20dB/Decade or -6dB/Octave


What is Inductive Reactance?

When an alternating or AC voltage is applied across an inductor the flow of current through it behaves very differently to that of an applied DC voltage. The effect of a sinusoidal supply produces a phase difference between the voltage and the current waveforms. In an AC circuit, the opposition to current flow through an […]


What is Capacitive Reactance?

When an alternating sinusoidal voltage is applied to the plates of a capacitor, the capacitor is first charged in one direction and then again in the opposite direction, changing polarity at the same rate as the AC supply voltage. This instantaneous change in voltage across the capacitor is opposed by the fact that it takes […]


What is AC Resistance?

Many AC resistive circuits such as heating elements and lamps consist of a pure ohmic resistance only and have negligible values of inductance or capacitance adding to its impedance. In such circuits we can use both Ohms Law and Kirchoff’s laws as well as simple circuit rules for calculating the voltage, current, impedance and power […]

What is Impedance?

Any ideal basic circuit element such as the resistor can be described mathematically in terms of its voltage and current and we saw previously that the voltage across a pure ohmic resistor is linearly proportional to the current flowing through it as defined by Ohm’s Law. If the voltage across a resistor varies sinusoidally with […]

Connecting Inductors Together

Inductors, like resistors and capacitors, can be connected together in series or parallel combinations. Increasing levels of inductance can be obtained by connecting the inductors in series, while decreasing levels can be obtained by connecting inductors in parallel. However, there are certain rules for connecting inductors in series or parallel and these are based on […]


Inductors In Parallel

Inductors are said to be connected together in “Parallel” when both of their terminals are respectively connected to each terminal of the other inductor or inductors. The voltage drop across all of the inductors in parallel will be the same. Then, Inductors in Parallel have a Common Voltage across them and in our example below […]


Inductors In Series

Inductors are said to be connected in “Series” when they are daisy chained together in a straight line, end to end. In the Resistors in Series tutorial we saw that the different values of the resistances connected together in series just “add” together and this is also true of inductance. Inductors in series are simply […]


What is Inductance?

“An Inductor is a coil of wire which opposes the flow of current through itself in the form of a magnetic field” When an electrical current flows through a length of wire a magnetic field is built up around the wire conductor. The direction of this magnetic field can be thought in terms of the […]

Connecting Capacitors Together

Like resistors, capacitors can be connected in series, parallel and series-parallel combinations. Placing capacitors in series effectively increases the thickness of the dielectric, decreases the total capacitance. The total capacitance of capacitors in series is calculated like the total resistance of parallel resistors. Connecting capacitors together in parallel effectively increases the area of the plates […]

Capacitors In Series

Capacitors are said to be connected together “in series” when they are effectively “daisy chained” together in a single line. The charging current ( IC ) flowing through the capacitors is the same for all capacitors as it only has one path to follow. Then, Capacitors in Series all have the same current so each […]


Capacitors In Parallel

Capacitors are said to be connected together “in parallel” when both of their terminals are respectively connected to each terminal of the other capacitor or capacitors. The voltage, Vs connected across all the capacitors that are connected in parallel is the same. Then, Capacitors in Parallel have a common voltage supply across them. CT = […]

Capacitor Types

The names that are used to describe the different types of capacitors are the names of the dielectric materials used in its construction because the performance of a capacitor is usually dependent upon the type of material that is used for its dielectric. Also like resistors, there are also variable types of capacitors which allow […]

Unit Of Capacitance

The SI unit of Capacitance is the Farad (abbreviated as F). it was named after the British physicist Michael Faraday and is defined as:- “Capacitor has the capacitance of One Farad when a charge of One Coulomb is stored on the plates by a voltage of One volt” Capacitance C is always positive and has […]

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