# Switching between outputs using irfz44n mosfet

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.

• "Switching between outputs using irfz44n mosfet", is this another way of saying "I'm trying to make a multiplexer(mux) using irfz44n"? – Harry Svensson Jun 20 at 15:46
• Yes.However, i would like to solve the problem in this circuit itself. I know there are simpler ways. – Nick Rogers Jun 20 at 15:47
• 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. – Harry Svensson Jun 20 at 15:53
• Should just be able to select the respective signal sources. – Nick Rogers Jun 20 at 15:58
• 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? – Harry Svensson Jun 20 at 16:10