Common source jfet amplifier lab manual

A typical common-source amplifier circuit is shown in Fig In this circuit, capacitors C c1 and C c2 are DC blocking capacitors, while C S is a bypass capacitor for the source resistor R S. Figure 2: A Typical Common Source Amplifier The small-signal approximate equivalent circuit for the amplifier of Fig.2 is presented in Fig 1. Design and setup the Common Source JFET/MOSFET amplifier and plot the frequency response. 2. Design and set up the BJT common emitter voltage amplifier with and without feedback and determine the gain- bandwidth product, input and output impedances. 3. Design and set-up BJT/FET i) Colpitts Oscillator, and ii) Crystal Oscillator 4. Lab 5 - JFET Circuits II. 1. Sets the gain through feedback. 2. Acts as a current source to increase the gain. 3. Increases the open-loop gain by bypassing the source resistor. 4. Sets the current through the JFETs. 5. Assures that the drain source voltage across both JFETs is approximately 12V.

Figure 1: Simple JFET Model. A more useful JFET model replaces the variable resistor with a variable current source whose current depends on the gate voltage VGS and the drain-source voltage, VDS, as shown in Fig. 2. The drain-source current is largest when the gate-source voltage VGS is zero, typically about 50mA. EE Microelectronic Devices Circuits Lab Manual MCW 3/12/ 2 Figure 1: Common source amplifier schematic 3. Hand design Biasing circuit The biasing circuit includes the gate resistors, the source resistor and the drain resistor. These should be chosen to provide adequate gain as well as permitting sufficient output swing. A. Problem - Increased Gain Common Source JFET Amplifier-Source Resistor Bypass. Bypassing the source resistor with a capacitor will also increase the gain. Build the circuit at right, which uses a bypasss capacitor. Use a regular capacitor, not a polarized electrolytic capacitor. Measure the gain of the circuit.

Lab 5 - JFET Circuits II. 1. Sets the gain through feedback. 2. Acts as a current source to increase the gain. 3. Increases the open-loop gain by bypassing the source resistor. 4. Sets the current through the JFETs. 5. Assures that the drain source voltage across both JFETs is approximately 12V. 1. Connecting Wires. Theory: Of the possible three configurations of JFET amplifiers, common source (CS) configuration is mostly used. The advantage of using CS configuration is that it has very high input impedance. Circuit diagram shows the FET amplifier of common source configuration. The biasing input and couplings are shown in the figure. 1. Measurement of operational amplifier parameters- Common Mode Gain, Differential Mode Gain, CMRR, Slew Rate. 2. Applications of OP-amp- OP-amp as summer amplifier, difference amplifier, integrator and differentiator. 3. Field effect Transistors- Single stage common source FET amplifier-plot of gain in dB Vs.