Question

what are the applic ations of LCR circuits in electrical engineering, i know about the apps in electronics; explain maybe inverters?

Answer 1

Variable tuned circuits
A very frequent use of these circuits is in the tuning circuits of analogue radios. Adjustable tuning is commonly achieved with a parallel plate variable capacitor which allows the value of C to be changed and tune to stations on different frequencies. For the IF stage in the radio where the tuning is preset in the factory the more usual solution is an adjustable core in the inductor to adjust L. In this design the core (made of a high permeability material that has the effect of increasing inductance) is threaded so that it can be screwed further in, or screwed further out of the inductor winding as required.
Filters

In the filtering application, the resistor R becomes the load that the filter is working into. The value of the damping factor is chosen based on the desired bandwidth of the filter. For a wider bandwidth, a larger value of the damping factor is required (and vice versa). The three components give the designer three degrees of freedom. Two of these are required to set the bandwidth and resonant frequency. The designer is still left with one which can be used to scale R, L and C to convenient practical values. Alternatively, R may be predetermined by the external circuitry which will use the last degree of freedom.
Low-pass filter
An RLC circuit can be used as a low-pass filter. The corner frequency, that is, the frequency of the 3dB point.

High-pass filter
The corner frequency is the same as the low-pass filter.

Band-pass filter
A band-pass filter can be formed with an RLC circuit by either placing a series LC circuit in series with the load resistor or else by placing a parallel LC circuit in parallel with the load resistor.

The shunt version of the circuit is intended to be driven by a high impedance source, that is, a constant current source.

Band-stop filter
a band-stop filter formed by a series LC circuit in shunt across the load. a band-stop filter formed by a parallel LC circuit in series with the load. The first case requires a high impedance source so that the current is diverted into the resonator when it becomes low impedance at resonance. The second case requires a low impedance source so that the voltage is dropped across the antiresonator when it becomes high impedance at resonance.
Oscillators
For applications in oscillator circuits, it is generally desirable to make the attenuation (or equivalently, the damping factor) as small as possible. In practice, this objective requires making the circuit's resistance R as small as physically possible for a series circuit, or alternatively increasing R to as much as possible for a parallel circuit. In either case, the RLC circuit becomes a good approximation to an ideal LC circuit. However, for very low attenuation circuits (high Q-factor) circuits, issues such as dielectric losses of coils and capacitors can become important.

Voltage multiplier
In a series RLC circuit at resonance, the current is limited only by the resistance of the circuit

If R is small, consisting only of the inductor winding resistance say, then this current will be large.

An equal magnitude voltage will also be seen across the capacitor but in antiphase to the inductor. If R can be made sufficiently small, these voltages can be several times the input voltage.

A similar effect is observed with currents in the parallel circuit. Even though the circuit appears as high impedance to the external source, there is a large current circulating in the internal loop of the parallel inductor and capacitor.
Pulse discharge circuit
An overdamped series RLC circuit can be used as a pulse discharge circuit. Often it is useful to know the values of components that could be used to produce a waveform this is described by the form:

Such a circuit could consist of an energy storage capacitor, a load in the form of a resistance, some circuit inductance and a switch - all in series. The initial conditions are that the capacitor is at voltage and there is no current flowing in the inductor. If the inductance is known, then the remaining parameters are given by the following - capacitance.:)

Answer 2

thank you how do i give you a medal ? the applications I was looking for in electrical engineering was think these circuits are used in inverter circuits to convert DC to AC; what practical applications of these