* * * FET source basic amplifier circuit For the * * source basic amplifier circuit using FET, it can correspond to the basic amplifier circuit connected in * * * configuration, except that FET is a voltage-controlled current source, that is, VCCS. * * * The basic amplification circuit of the source configuration is shown in the figure. Compared with * * * source and * * * emitter amplifier circuits, they differ only in the types of bias circuits and controlled sources. As long as the equivalent circuit of a micro variable is drawn, it is a problem of solving the circuit. (a) Use junction field effect transistor (b) Connect the basic amplifier circuit (1) using insulated gate field effect transistor diagram. The DC analysis diagram * * * draws the DC path of the basic amplification circuit of the * * * source, as shown in the figure. In the figure, Rg 1 and Rg2 are gate bias resistance, r is source resistance, and Rd is drain load resistance. They Respectively correspond to Rb 1, Rb2, re and Rc of the * * * emittance basic amplification circuit. Moreover, as long as the gate-source PN junction of junction field effect transistor works in reverse bias and there is no gate current, the DC path and AC path of JFET and MOSFET are the same. According to fig. 03.29, the following formula VG = vddrg2/(rg1+rg2) vgsq = VG-vs = VG-idqridq = IDSS [1-(vgsq/vgs (off))] 2vdsq = vdd-idq (rd+) Ac analysis draws the micro-variable equivalent circuit of the circuit, as shown in the figure. Compared with bipolar transistor, the input resistance is infinite and quite open. Current source of VCCS? The output resistor rds is also connected in parallel. In the simplified model of bipolar transistor, the output resistance is considered as an open circuit, which can be temporarily retained here. Other parts are the same as bipolar transistor amplifier circuit. Figure Micro-variable equivalent circuit ① Voltage amplification output voltage is if there is signal source internal resistance RS? =-gmrl' Ri/(Ri+RS) where ri is the input resistance of the amplifier circuit. ② input resistance ri =? = rg 1∑rg2③ The output resistance is the output resistance of the calculation amplifier circuit, which can be plotted according to the calculation principle of two-port network. Calculating the circuit model of Ro with graph

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Basic amplification circuit of field effect transistor source

Basic amplification circuit of field effect transistor source

For the * * * source basic amplifier circuit with field effect transistor, the connected basic amplifier circuit can be configured corresponding to * * *, but the field effect transistor is a voltage-controlled current source, that is, VCCS. * * * The basic amplification circuit of the source configuration is shown in the figure. Compared with * * * source and * * * emitter amplifier circuits, they differ only in the types of bias circuits and controlled sources. As long as we draw the equivalent circuit of the micro variable, it is a problem of solving the circuit.

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(a) using junction field effect transistor (b) using insulated gate field effect transistor.

Figure * * * Basic amplifier circuit with source configuration connection

(1).DC analysis

Figure * * * DC path of source basic amplifier circuit

Draw the DC path of the * * * source basic amplifier circuit, as shown in the figure. In the figure, Rg 1 and Rg2 are the gate bias resistance, r is the source resistance and Rd is the drain load resistance. They Respectively correspond to Rb 1, Rb2, re and Rc of the * * * emittance basic amplification circuit. Moreover, as long as the gate-source PN junction of junction field effect transistor works in reverse bias and there is no gate current, the DC path and AC path of JFET and MOSFET are the same.