When a part of output signal is fed back to the input of circuit through a suitable network, the process is called feedback. Feedback is of two types Positive and Negative feedback in amplifier Negative feedback in amplifier In negative feedback, the feedback signal is opposite in phase to the input signal and this lead … Read more
Hartley oscillator Definition Fig. 4 shows the circuit diagram of a Hartley oscillator using a transistor in C.E. configuration. In hartley oscillator, tank circuit consists of L1, L2 and C1. Stabilized 1self-bias to the amplifier is provided by R1, R2, Re and Ce. Radio frequency choke is used to provide load for the collector and … Read more
Construction of tuned collector oscillator It consists of a tank circuit or LC tuned circuit connected to the Collector of the transistor. Hence, the name of this oscillator is tuned collector oscillator. The stabilized self bias to the amplifier is provided by the arrangement consisting of R1 , R2 , R3 and Ce. The coil … Read more
What is Operational Amplifier An operational amplifier (OP-AMP) is a very high gain differential Amplifier with high input impedance and low input impedance. It is direct coupled and uses negative feedback. It is called operational amplifier because it can perform mathematical operation like subtraction, addition, differentiation and integration etc. the symbolic representation of Operational amplifier … Read more
Fig. 6 Shows the circuit diagram of Colpitts oscillator. What is Colpitts Oscillator? In this oscillator, tank circuit consists of C1,C2, and L. Stabilized self-bias to the amplifier is provided by R1 R2 Re and Ce. Radio frequency (RF) choke is used to permit an easy flow of d.c., whereas a capacitor Cc permits a.c. … Read more
Fig. 8 shows the circuit diagram of RC phase shift oscillator using transistor in CE configuration. In this circuit, stabilized self-bias to the amplifier is provided by R1, R2, R3, R4 and Ce. Phase shift network (R-C network) provides a phase shift of 180o essential for positive feedback. The feedback signal is coupled through R‘ … Read more
What is Oscillator ? A device used to produce sinusoidal or non sinusoidal ( e.g. square wave ) wave forms without the application of an external input signal is known as an oscillator. In an oscillator, D.C power supply is connected to the input. Thus, the oscillator converts D.C power into A.C power of desired … Read more
Fig. 25 shows the circuit diagram of common drain jfet amplifier or source follower. The output is taken between the source and the ground. Expression for common drain jfet amplifier The equivalent circuit of fig. 25 is shown in fig. 26. Since rd and RS are in parallel, so their equivalent resistance is given by … Read more
Fig. 23 shows the circuit of a common source n-channel JFET amplifier. When the positive half cycle of applied input signal voltage vgs is superimposed on VGG, then the gate source voltage becomes less negative. As a result of this, the drain current increases. Since drain current flows through RL, so the voltage drop across … Read more
Transformer Definition For many purposes, it is necessary to change (or transform) an alternating voltage from one to another of greater or smaller value. This is done with a device called a transformer using the principle of mutual induction. A transformer is a static device that transfers alternating current from one circuit to another at an equal … Read more