Version 4.1
SHEET 1 1540 852
WIRE -864 64 -896 64
WIRE -800 64 -864 64
WIRE -720 64 -800 64
WIRE 272 64 -624 64
WIRE 352 64 272 64
WIRE 448 64 352 64
WIRE 480 64 448 64
WIRE 272 112 272 64
WIRE -672 144 -672 128
WIRE -640 144 -672 144
WIRE -800 176 -800 64
WIRE -784 176 -800 176
WIRE -672 176 -672 144
WIRE -672 176 -704 176
WIRE 448 176 448 64
WIRE -272 224 -352 224
WIRE -144 224 -208 224
WIRE 16 224 -64 224
WIRE -896 304 -896 64
WIRE -128 304 -896 304
WIRE -128 352 -128 304
WIRE -896 368 -896 304
WIRE 16 368 16 224
WIRE 16 368 -96 368
WIRE 80 368 16 368
WIRE 224 368 160 368
WIRE 272 368 272 192
WIRE 272 368 224 368
WIRE -672 384 -672 176
WIRE -352 384 -352 224
WIRE -352 384 -544 384
WIRE -288 384 -352 384
WIRE -160 384 -288 384
WIRE 32 400 -96 400
WIRE -544 432 -544 384
WIRE 272 464 272 368
WIRE -672 496 -672 464
WIRE 32 496 32 400
WIRE -544 544 -544 512
WIRE -544 544 -608 544
WIRE -896 672 -896 448
WIRE -672 672 -672 592
WIRE -672 672 -896 672
WIRE -128 672 -128 416
WIRE -128 672 -672 672
WIRE 32 672 32 576
WIRE 32 672 -128 672
WIRE 208 672 32 672
WIRE 272 672 272 544
WIRE 272 672 208 672
WIRE 448 672 448 256
WIRE 448 672 272 672
WIRE 208 704 208 672
FLAG 208 704 0
FLAG 352 64 Vout
FLAG 224 368 FB
FLAG -288 384 error
FLAG -640 144 pass_tran_base
FLAG -864 64 Vin
SYMBOL voltage -896 352 R0
SYMATTR InstName V1
SYMATTR Value 5V
SYMBOL res 256 96 R0
SYMATTR InstName R1
SYMATTR Value 230R
SYMBOL res 256 448 R0
WINDOW 3 46 68 Left 2
SYMATTR Value 100R
SYMATTR InstName R2
SYMBOL res 432 160 R0
SYMATTR InstName R_load
SYMATTR Value 3.3R
SYMBOL pnp -624 128 M270
SYMATTR InstName Q1
SYMATTR Value 2SA2071P5
SYMBOL res -688 160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 500R
SYMBOL res -688 368 R0
SYMATTR InstName R4
SYMATTR Value 500R
SYMBOL npn -608 496 M0
SYMATTR InstName Q2
SYMBOL res -560 416 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL cap -208 208 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 47n
SYMBOL res -48 208 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 10k
SYMBOL voltage 32 480 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 1V
SYMBOL res 176 352 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R8
SYMATTR Value 10k
SYMBOL OpAmps\\UniversalOpAmp2 -128 384 M0
WINDOW 123 -137 50 Left 2
SYMATTR InstName U1
TEXT -784 -440 Left 5 ;Simple linear reg using discretes
TEXT -8 320 Right 2 ;op amp 1
TEXT -1024 728 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.
TEXT -728 736 Left 1 ;You may republish or reuse this circuit implementation and text providing this line and the following lines are included.\nThis circuit implementation designed by Keith Wallbanks. Originally released on analogsimulation.co.uk\nThis circuit is provided as is without warranty of any kind. This text is intended to implement the MIT licence.
LINE Normal 64 256 64 256 2