Help to measure the output voltage of a MOSFET switch

[ReportX]

I am trying to measure the output voltage of a simple N-Channel MOSFET switch module based on IFR520.

To achieve this goal I have added a Voltmeter/Scope Probe between the MOSFET drain (V-) and V+ but I always get a +5V read in the voltmeter when SIG is LOW, when SIG is HIGH or even when the negative terminal of the voltmeter is not connected.

No need to say the same tests with this MOSFET switch module on a breadboard worked as expected.

I thought I may use a Voltmeter/Scope Probe to measure voltages between any two given circuit points but it looks like it is measuring the voltage between the positive terminal and ground.

IFR520_MOSFET_Module_Schematics.zip

[pfalstad]

Sorry for never responding. The MOSFET drain is always at ground regardless of what SIG is, because it's not connected to anything (except the voltmeter which is ideal, so it doesn't conduct current).

If I add a large resistor in parallel with the voltmeter, it works. Maybe this is similar to #965 where the issue is the ideality of the voltmeter.