Version 4.1 SHEET 1 3772 2480 WIRE 1968 1776 1808 1776 WIRE 2208 1776 1968 1776 WIRE 1808 1808 1808 1776 WIRE 2208 1824 2208 1776 WIRE 1968 1840 1968 1776 WIRE 1808 1904 1808 1888 WIRE 2208 1920 2208 1904 WIRE 2304 1920 2208 1920 WIRE 2208 1952 2208 1920 WIRE 1968 2000 1968 1920 WIRE 2064 2000 1968 2000 WIRE 2144 2000 2064 2000 WIRE 1648 2032 1392 2032 WIRE 1744 2032 1648 2032 WIRE 1968 2032 1968 2000 WIRE 1968 2032 1808 2032 WIRE 2208 2080 2208 2048 WIRE 2288 2080 2208 2080 WIRE 2320 2080 2288 2080 WIRE 2592 2080 2384 2080 WIRE 3008 2080 2768 2080 WIRE 1392 2096 1392 2032 WIRE 2592 2096 2592 2080 WIRE 3008 2096 3008 2080 WIRE 1968 2144 1968 2032 WIRE 3008 2192 3008 2176 WIRE 3008 2192 2816 2192 WIRE 2208 2208 2208 2080 WIRE 2592 2208 2592 2176 WIRE 2656 2208 2592 2208 WIRE 2688 2272 2640 2272 WIRE 2768 2272 2768 2080 WIRE 2768 2272 2688 2272 WIRE 1392 2304 1392 2176 WIRE 2816 2304 2816 2192 WIRE 1968 2336 1968 2224 WIRE 2208 2336 2208 2288 WIRE 2592 2400 2592 2304 WIRE 2816 2400 2816 2384 FLAG 2208 2336 0 FLAG 1808 1904 0 FLAG 2304 1920 output FLAG 2592 2400 0 FLAG 2288 2080 emmitter FLAG 2064 2000 base FLAG 2688 2272 gate FLAG 2656 2208 drain FLAG 1648 2032 RF_input FLAG 1968 2336 0 FLAG 1392 2304 0 FLAG 2816 2400 0 SYMBOL NJF 2640 2208 M0 SYMATTR InstName Q1 SYMATTR Value 2N3819 SYMBOL RES 2192 1808 R0 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL res 2192 2192 R0 SYMATTR InstName R2 SYMATTR Value 2k SYMBOL VOLTAGE 1808 1792 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 12 SYMBOL npn 2144 1952 R0 SYMATTR InstName Q3 SYMATTR Value 2N2222 SYMBOL res 2576 2080 R0 SYMATTR InstName R3 SYMATTR Value 1R SYMBOL res 1952 2128 R0 SYMATTR InstName R4 SYMATTR Value 10k SYMBOL res 1952 1824 R0 SYMATTR InstName R5 SYMATTR Value 100k SYMBOL cap 1744 2048 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName C1 SYMATTR Value 1µ SYMBOL voltage 1392 2080 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 3 -88 111 Left 2 SYMATTR Value SINE(0 100m 100k) SYMATTR InstName V2 SYMBOL voltage 3008 2080 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value SINE(0 100m 1k) SYMBOL voltage 2816 2288 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 3 24 44 Left 2 SYMATTR Value -2.8V SYMATTR InstName V4 SYMBOL cap 2384 2064 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 10µ TEXT 1232 2400 Left 2 !.tran 0 3m 0 100n TEXT 1304 1072 Left 5 ;Varying the gain of an amplifier using a variable resistance FET. TEXT 1280 1312 Left 2 ;We start with the circuit "common emmitter-3"\nin the simpler circuits section,\nthen add the variable resistance FET circuit. TEXT 2512 1672 Left 4 ;Variable resistance\nFET circuit. TEXT 2960 1760 Left 2 ;incoming signal strength\nmeasurement, \nsets amplifier gain. TEXT 2688 2328 Left 2 ;DC bias\nfor FET. TEXT 2280 1944 Left 2 ;(collector) TEXT 1280 1712 Left 3 ;Input to cm\nemmitter amp.\nfrom IF stage. TEXT 2480 1192 Left 4 ;instructions TEXT 2480 1240 Left 2 ;click on run\nthen click on "RF_input" to plot it.\nthen click on the plot window then on plot settings / add plot pane\nthen click on "gate" to plot it\nthen click on the plot window and plot settings/add plot pane\nthen click on "output" to plot it TEXT 1840 1704 Left 4 ;Common emmitter amp TEXT 1288 1240 Left 2 ;This type of circuit will be usefull for AGC (automatic gain control),\nas part of a reciever. TEXT 1296 1184 Left 4 ;Circuit description TEXT 1112 1512 Left 7 ;Varying the gain of an amplifier using \na variable resistance FET. RECTANGLE Normal 2912 2432 2512 1744 2 RECTANGLE Normal 2384 2368 1744 1744 2 RECTANGLE Normal 1552 2336 1232 1744 2 RECTANGLE Normal 3264 2256 2944 1744 2