Simplest sinusoidal variable frequency oscillator is amstrong circuit. Simplest sinusoidal constant frequency oscillator is crystal oscillator. Parasitic oscillation is caused by transistor inter electrode capacitance. If you movie towards an oscillating circuit its frequency increases because of hand capacitance. Frequency stability is maximum in wein bridge oscillator. Practically in order to change frequency of oscillation …
FET FET has square law characteristics. It has negative temperature coefficient. High immunity against radiation. FET has least noise. Pinch off voltage of FET is 5 volt. FET is classified in to JFET ( junction field effect transistor) and MOSFET (metal oxide semiconductor FET). MOSFET has highest input impedance. Quiescent current of FET is ID. …
Carrier is generated by high precision, temperature controlled crystal oscillator, operates at a frequency 124 KHz. Output of this master oscillator is feed to harmonic generator, which supplies super group carrier frequencies. Required harmonics are selected by filters. 124 KHz frequency is subdivided into 4 KHz. This 4 KHz is then used in odd and …
Audio power amplifiers Power amplifiers handles large signals (not very large). Size of power transistor is large, to dissipate heat. Tuned amplifier is used in RF application. Class A power amplifier uses one transistor, this transistor never turn off which is its main disadvantage. Driver stage commonly uses class A. Class A amplifier is most …
Emitter is moderate size and heavily doped. Collector is large in size and moderately doped. Base is thin and lightly doped. When collector supply is 5V then collector cut off voltage is 5V. Zero signal condition is when transistor see dc load. Cut-off region – both junctions are reverse biased, Saturation region – both junctions …