I am trying to model a light-sensitive resistive element in LTspice, and I can't get it to work even after countless hours and google sessions.
Imagine an ohmic sensor of 1000kOhm, which varies its resistance by 10% at a rate of 50Hz, because you illuminate it with a 50Hz strobe or similar. Now if you apply an AC voltage of 1V rms, 600Hz to this resistor, then you should get a nice amplitude-modulated current with a mean value of ca. 1mA rms out of your model. Specifically, if you ran an FFT on this, you'd see a large peak at 600Hz, and two sidebands at 550Hz and 650Hz each. I'm interested in how an AM signal generated this way is degraded by additional stray voltages and resistance down the line. However, I simply can't coax LTSpice to give me the equivalent of a modulated Ohmic resistance, which is what I need to simulate this.
Can anyone help and maybe even draw up an equivalent circuit? This is driving me nuts.
Thanks for reading.
Imagine an ohmic sensor of 1000kOhm, which varies its resistance by 10% at a rate of 50Hz, because you illuminate it with a 50Hz strobe or similar. Now if you apply an AC voltage of 1V rms, 600Hz to this resistor, then you should get a nice amplitude-modulated current with a mean value of ca. 1mA rms out of your model. Specifically, if you ran an FFT on this, you'd see a large peak at 600Hz, and two sidebands at 550Hz and 650Hz each. I'm interested in how an AM signal generated this way is degraded by additional stray voltages and resistance down the line. However, I simply can't coax LTSpice to give me the equivalent of a modulated Ohmic resistance, which is what I need to simulate this.
Can anyone help and maybe even draw up an equivalent circuit? This is driving me nuts.
Thanks for reading.