English: Simple diode detector used to extract the envelope of an amplitude-modulated signal. The green AM signal uses a 50 kHz 2 Vpp carrier wave multiplied by a 4 Vpp 1 kHz input sine wave with a 3 V DC offset. The red output signal is the voltage across the capacitor, which is alternatively charged (whenever the AM signal's voltage is higher that the capacitor's voltage) and then discharged through the resistor. The resistor and capacitor values are selected to ensure their RC time constant is low enough so that the capacitor can discharge fast enough to trace the signal as it is falling, but large enough to ensure its cutoff frequency is above the input signal's maximum frequency, to prevent attenuation. This circuit specifically used a 1 nF capacitor and 100 kΩ resistor with a silicon diode.
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Circuitjs code
$ 4 5.0000000000000004e-8 18.278915558614752 72 5 50 5e-11
d 352 -192 432 -192 2 default
r 496 -192 496 -112 0 100000
w 432 -192 496 -192 0
c 432 -192 432 -112 0 1e-9 3.907751647100082 0
g 432 -112 432 -96 0 0
g 496 -112 496 -96 0 0
O 496 -192 528 -192 0 0
R 240 -208 192 -208 0 1 50000 1 0 0 0.5
212 240 -192 288 -192 0 2 (a*b)
R 240 -144 192 -144 0 1 1000 2 3 0 0.5
w 240 -208 240 -192 0
w 240 -160 240 -144 0
g 336 -160 336 -128 0 0
w 336 -192 352 -192 0
403 64 -32 656 176 0 13_32_0_4614_4.999911173719252_0.0019071054226908468_-1_3_13_3_6_0
38 1 F1 0 1 10000 -1 Resistance
Captions
Simple diode detector used to extract envelope of an amplitude-modulated signal