Hi dear enthusiasts, I am trying to use the following circuit (in the attachments) to switch between multiple resistors using a multiplexer. Initially I had different values of resistors attached to every channel, but since I was getting very strange and HUGE!! results, I grounded all the channels except the first channel and just connected a 120 ohm resistor. I am measuring resistor readings of magnitudes of Mega ohms and I have no idea how such huge values of resistance are showing up at all. I am not sure what I am doing wrong and I really really appreciate any help.

You cannot measure resistance directly in an active (powered) circuit. You must measure the voltage and current at the relevant points and use Ohm's Law to calculate the resistance. SImulators are jsut like real circuits in this regard. You also need to use voltages and currents which are compatible with the devices in the circuit. With 12 V applied to Y2 you will get ~100 mA flowing through S1 of the ADG608 when it is enabled. I did not look up the specs but suspect that that is too much current. I only have a few minutes now and cannot draw up a circuit for you. Connect V1 to Y2 through an ammeter. This will let you measure the current through the mux. Also measure the voltage at Y1. Then the switch resistance Rs = (V1 - V(Y1))/I(V1). Lynn

Multisim and Ultiboard

Odd results from ADG608 multiplexer

Solved!

NI please note! ADIsimPE makes it much easier than MULTISM to identify suitable replacements for placed components. Rather than listing all ADG's in the library, it only lists 8 channel switches when looking for 8 channel replacements.:manwink:

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Multisim and Ultiboard

Odd results from ADG608 multiplexer

Re: Odd results from ADG608 multiplexer