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In the circuit shown, the input voltage to the op-amp ua741 is 1V and the output will be 5.7V, which switches the bottom left irfz44n mosfet on and the off voltage irfz44n mosfet off. So i would expect the voltage from the first voltage divider [0.8*12= 9.6- 0.7= 8.9 Volts] which is 8.9V to appear at the output (at the junction where sources of both mosfets and the 10kohm pull down resistor meet). However i get 2.13 volts with minute fluctuations. Why is this happening? How do i fix this. Threshold voltage of irfz44n is 4V.

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  • \$\begingroup\$ "Switching between outputs using irfz44n mosfet", is this another way of saying "I'm trying to make a multiplexer(mux) using irfz44n"? \$\endgroup\$ – Harry Svensson Jun 20 at 15:46
  • \$\begingroup\$ Yes.However, i would like to solve the problem in this circuit itself. I know there are simpler ways. \$\endgroup\$ – Nick Rogers Jun 20 at 15:47
  • \$\begingroup\$ Slightly off topic but is this mux supposed to have a lot of current going through it, like routing power, or is it supposed to just do math, such as passing signals, like a typical mux. \$\endgroup\$ – Harry Svensson Jun 20 at 15:53
  • \$\begingroup\$ Should just be able to select the respective signal sources. \$\endgroup\$ – Nick Rogers Jun 20 at 15:58
  • \$\begingroup\$ Okay, so there should be a total of three inputs and one output, two inputs A, B and one input S that decides which of A and B that should go to output Y I guess, where are these 4 points in your schematic? \$\endgroup\$ – Harry Svensson Jun 20 at 16:10

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