# What is the purpose of tank circuit ?

A tank circuit, also known as a resonant circuit or LC circuit, is a combination of inductance (L) and capacitance (C) connected in parallel or in series. The primary purpose of a tank circuit is to resonate at a specific frequency. This resonance phenomenon allows the tank circuit to store and exchange energy efficiently. Here’s a detailed explanation of the purpose and applications of a tank circuit:

1. Resonance:
• The central purpose of a tank circuit is to exhibit resonance. Resonance occurs when the inductive reactance (XL) and capacitive reactance (XC) in the circuit are equal and opposite, resulting in cancellation. This balanced condition causes the impedance of the tank circuit to be minimized, allowing it to pass maximum current at a particular frequency.
2. Frequency Selection:
• By choosing appropriate values for the inductance and capacitance, a tank circuit can be tuned to resonate at a specific frequency. This frequency is determined by the relationship between the inductance, capacitance, and the angular frequency (ω) according to the formula �=1��ω=LC​1​. Tank circuits are widely used in radio frequency (RF) applications for selecting and tuning specific frequencies.
3. Bandwidth Control:
• Tank circuits play a crucial role in controlling the bandwidth of resonant circuits. The bandwidth is the range of frequencies around the resonant frequency where the circuit exhibits efficient energy transfer. Proper design of the tank circuit allows for precise control over the bandwidth, which is essential in applications like communication systems and signal processing.
4. Signal Filtering:
• Tank circuits are employed for signal filtering, allowing specific frequencies to pass through while attenuating others. In this application, the tank circuit can be designed to resonate at the desired frequency, effectively passing signals within that frequency range and blocking others. This is commonly used in radio frequency filters.
5. Oscillators:
• Tank circuits are essential components in the design of oscillators, which generate periodic waveforms. By incorporating positive feedback through an amplifier, a tank circuit can sustain oscillations at its resonant frequency. Oscillators find applications in electronic devices such as RF transmitters, signal generators, and clock circuits.
6. Antenna Matching:
• In RF and communication systems, tank circuits are utilized to match the impedance of antennas to the transmission line. This impedance matching ensures efficient power transfer between the transmission line and the antenna, optimizing the performance of the communication system.
7. Filtering and Amplification in RF Amplifiers:
• Tank circuits are often part of RF amplifiers to provide filtering and selectivity. They help in amplifying signals at specific frequencies while attenuating unwanted frequencies.
8. Tuning Circuits:
• Tank circuits are commonly found in tuning circuits, such as those used in AM and FM radios. These circuits allow users to adjust the resonant frequency, enabling the tuning of different radio stations.

In summary, the purpose of a tank circuit is to resonate at a specific frequency, and it finds extensive applications in tuning circuits, signal filtering, oscillators, and impedance matching in various electronic systems and communication devices.