PE: Field effect transistor. Oscilloscope applications - practical exercises with LTSpice: Junction field effect transistor

Field effect transistor. Oscilloscope applications - practical exercises with LTSpice

Junction field effect transistor

Exercise 1:

Plot the output and transition characteristics of a unipolar junction transistor (JFET) N-channel depletion mode - BF245C. Use the model:

.MODEL BF245C NJF(VTO=-5.0014 BETA=5.43157E-4 BETATCE=-0.5 LAMBDA=2.71505E-2 RD=1.20869E1 RS=1.20869E1 CGS=2.00000p CGD=2.00000p PB=1.24659 IS=3.64346E-16 XTI=3 AF=1 FC=0.5 N=1 NR=2 MFG=PHILIPS)

as the Spice Directive. Create a layout as shown in the figure below:

Determine the parameters: \(I_{DSS}\) (current-source saturation parameter), \(U_{GSoff}\) (gate-source cut-off voltage), \(r_d\) (dynamic resistance) and \(g_m\) (transconductance). When you're done, compare the result with the video.