Question

Q.1 (25 Pt.): Simulate the following circuit used for sensors with differential outputs. You may use DC or sine-wave signals to demonstrate the behavior. You are to use PSIM (demo version should be more than enough.) R can be of any value, e.g., 1 k 2. V R R • Vout R R ww V2

Answer 1

* PSIM - (untitled1"] File Edit View Subcircuit Elements Simulate Options Utilities Window Help DGA6 Xem 0 MX 2013 av AAD | Simview - [C:\Users\dileep\AppData\Local\Temp\temp.smv] File Edit Axis Screen Measure Analysis View Options Label Settings Window Help 22 12 T TA FFT DATA A V3 1K 100Hz 0.5 M -0.5 100Hz ,2V 4 10 Time (ms) - C tº U V 5 ms LÃI PF P V3 Ready S THD + womens 100%

from the simulation result above we can easily understand the behavior of the circuit, the waveform obtained shows the output of the third op-amp, it can be easily understood from the figure that first two op-amps work as unity gain voltage followers, and so that their output will be same as that of input and these ouputs are given to a difference amplifier that too having gain '1' as it's input resistor and feedback resistor value is 1K so as their ratio that is gain=1 , and so as we get the output shown.

for better understanding please refer the simulation waveform below that consist of  output of all the 3 op-amps

please note that 3V, 100Hz and 2V, 100Hz are the output of the first 2 opamps in blue and green that is V4 and V5 and red waveform V3 is the output of the final op-amp that is 1V, 100Hz difference of the first two signals, and the timperiod of all the signals are same that is T=1/F=1/100=0.01S or 10mS and it is also important to know that the difference amplifier inverts it's input , as such is the phase shift at the output.

X * PSIM - (untitled1"] File Edit View Subcircuit Elements Simulate Options Utilities Window Help % Belmoxalma 6 x 12 A 113 DOIX Simview - [C:\Users\dileep\AppData\Local\Temp\temp.smy] File Edit Axis Screen Measure Analysis View Options Label Settings Window Help 2017 DATA F ... A V3 V5 3 V 1K 1K 2 100Hz V 1 0 1K 1K -1 M -2 100Hz ,2V -3 0 0.002 0.004 0.006 0.008 0.01 Time (5) V3 IN N U tok i ms iki PF P S THD Ready MM ++ ++ ** KEE OD K-PI 100%