Version 4.1
SHEET 1 1540 808
WIRE -864 128 -896 128
WIRE -800 128 -864 128
WIRE -720 128 -800 128
WIRE 272 128 -624 128
WIRE 352 128 272 128
WIRE 448 128 352 128
WIRE 480 128 448 128
WIRE 272 176 272 128
WIRE -672 208 -672 192
WIRE -640 208 -672 208
WIRE -800 240 -800 128
WIRE -784 240 -800 240
WIRE -672 240 -672 208
WIRE -672 240 -704 240
WIRE 448 240 448 128
WIRE -272 288 -352 288
WIRE -144 288 -208 288
WIRE 16 288 -64 288
WIRE -896 368 -896 128
WIRE -128 368 -896 368
WIRE -128 416 -128 368
WIRE -896 432 -896 368
WIRE 16 432 16 288
WIRE 16 432 -96 432
WIRE 80 432 16 432
WIRE 224 432 160 432
WIRE 272 432 272 256
WIRE 272 432 224 432
WIRE -672 448 -672 240
WIRE -352 448 -352 288
WIRE -352 448 -544 448
WIRE -288 448 -352 448
WIRE -160 448 -288 448
WIRE 32 464 -96 464
WIRE -544 496 -544 448
WIRE 272 528 272 432
WIRE -672 560 -672 528
WIRE 32 560 32 464
WIRE -544 608 -544 576
WIRE -544 608 -608 608
WIRE -896 736 -896 512
WIRE -672 736 -672 656
WIRE -672 736 -896 736
WIRE -128 736 -128 480
WIRE -128 736 -672 736
WIRE 32 736 32 640
WIRE 32 736 -128 736
WIRE 208 736 32 736
WIRE 272 736 272 608
WIRE 272 736 208 736
WIRE 448 736 448 320
WIRE 448 736 272 736
WIRE 208 768 208 736
FLAG 208 768 0
FLAG 352 128 Vout
FLAG 224 432 FB
FLAG -288 448 error
FLAG -640 208 pass_tran_base
FLAG -864 128 Vin
SYMBOL voltage -896 416 R0
SYMATTR InstName V1
SYMATTR Value 5V
SYMBOL res 256 160 R0
SYMATTR InstName R1
SYMATTR Value 230R
SYMBOL res 256 512 R0
WINDOW 3 46 68 Left 2
SYMATTR Value 100R
SYMATTR InstName R2
SYMBOL res 432 224 R0
SYMATTR InstName R_load
SYMATTR Value 3.3R
SYMBOL pnp -624 192 M270
SYMATTR InstName Q1
SYMATTR Value 2SA2071P5
SYMBOL res -688 224 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 500R
SYMBOL res -688 432 R0
SYMATTR InstName R4
SYMATTR Value 500R
SYMBOL npn -608 560 M0
SYMATTR InstName Q2
SYMBOL res -560 480 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL cap -208 272 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 47n
SYMBOL res -48 272 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL voltage 32 544 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 1V
SYMBOL res 176 416 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 10k
SYMBOL OpAmps\\UniversalOpAmp2 -128 448 M0
WINDOW 123 -137 50 Left 2
SYMATTR InstName U1
TEXT -784 -440 Left 5 ;Simple linear reg using discretes
TEXT -8 384 Right 2 ;op amp 1
TEXT -1024 792 Left 2 !.tran 10m
TEXT -992 -216 Left 2 ;this linear regulator regulates from 5V down to 3.3V, \nits inefficient in percentage terms but in terms of watts\nit only dissipates 1A x (5V-3.3V) = 1.7W.
TEXT -968 -248 Left 4 ;description
TEXT -8 -328 Left 4 ;instructions
TEXT 0 -288 Left 2 ;click on run\nthen click on the "Vin" net\nthen click on the "Vout" net\nclick on the plot window,\nthen click on plot settings/add plot pane.\n then click on R_load to plot the output current\nclick on the plot window,\nthen click on plot settings/add plot pane.\nthen click on the "FB" net\nthen click on the "error" net\nthen click on the "pass_tran_base" net
TEXT -944 -368 Left 2 ;I have used discrete components here so you can see the internal Voltages, a real circuit would likely use an IC instead.
LINE Normal 64 320 64 320 2