Version 4.1
SHEET 1 2152 756
WIRE -448 64 -544 64
WIRE 144 64 -80 64
WIRE 256 64 144 64
WIRE 448 64 336 64
WIRE 464 64 448 64
WIRE -80 96 -80 64
WIRE -544 128 -544 64
WIRE 464 144 464 64
WIRE -544 256 -544 208
WIRE -80 256 -80 176
WIRE 464 256 464 208
WIRE 464 256 400 256
WIRE 400 272 400 256
WIRE -448 320 -448 288
WIRE -544 432 -544 400
WIRE -448 432 -448 400
WIRE -544 544 -544 512
FLAG -544 256 0
FLAG 400 272 0
FLAG 144 64 Var_freq_sq_wave
FLAG 448 64 Vout
FLAG -544 544 0
FLAG -448 432 0
FLAG -544 400 t
FLAG -448 288 w
FLAG -448 64 sine
FLAG -80 256 0
SYMBOL cap 480 144 M0
SYMATTR InstName C1
SYMATTR Value 20n
SYMBOL res 352 48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 100R
SYMBOL bv -544 112 R0
SYMATTR InstName B1
SYMATTR Value V=sin(1000*2*pi*V(w)*V(t))
SYMBOL voltage -448 304 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
WINDOW 3 -51 98 Left 2
SYMATTR Value PULSE(1 1000 10u 4m 1 1 10)
SYMATTR InstName V1
SYMBOL voltage -544 416 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 1 0 1 1 1 10)
SYMBOL bv -80 80 R0
WINDOW 3 -137 106 Left 2
SYMATTR Value V=limit(0, 10, 1E5*V(sine) )
SYMATTR InstName B2
TEXT 0 296 Left 2 !.tran 0 1m 0 10n
TEXT 664 104 Left 2 ;click on run\nthen click on "Var_freq_sq_wave" to plot its voltage\nclick on the plot window, then on plot settings/add plot pane.\nthen click on "Vout" to plot its voltage
TEXT 656 56 Left 4 ;Instructions, RC cct.
TEXT 136 -144 Left 5 ;RC circuit.
TEXT -568 -32 Left 2 ;This block creates an increasing\nfrequency square wave.\nyou don't have to understand this cct. block
TEXT 672 280 Left 4 ;Circuit description
TEXT 560 320 Left 2 ;The idea here is to understand the RC circuit.\nyou don't need to understand the block on the left which creates \nthe variable frequency square wave \n \nThe RC circuit behaves as a low pass filter, \nthe lower frequencies on the left of the graph pass through without attenuation.\nthe higher frequencies on the right of the graph are attenuated.\nthe next circuit shows the same thing but in a different format \n(frequency response).
RECTANGLE Normal -576 576 48 -48 2