Tuned amplifiers

Amplifier is an electronic device used to amplify signals.  The three types of amplifiers are dc amplifiers, audio frequency amplifiers and radio frequency amplifiers. An amplifier which amplifies signal of specific frequency or narrowband of frequencies is known as tuned amplifier. Tuned amplifiers are preferred in radiofrequency signal amplification. A tuned amplifier consists of an inductor and a variable capacitor. Resonance allows this circuit to select a particular frequency or narrowband of frequencies. Resonant frequency is the frequency of the midpoint of resonance frequency band. These amplifiers provide high gain due to its high impedance. Some advantages of tuned amplifiers are high selectivity of frequencies, smaller power loss and smaller collector voltage. The two types of tuned amplifiers are small signal tuned amplifiers and large signal tuned amplifiers. Some parasitic oscillations may arise in tuned amplifiers causing negative results. This can be eliminated by methods like changing the circuit parameters, changing wiring, rearranging the circuit components, changing the transistor, usage of neutralization and usage of additional bypassing. A number of tuned circuits are used in stagger-tuned amplifiers where overall response exhibits maximal flatness around resonant frequency.