I notice that some high-end multimeters have a 'Guard' terminal. If I wanted to setup a practical bench demonstration of the use and benefit of this facility, what would I have to do ?
I notice that some high-end multimeters have a 'Guard' terminal. If I wanted to setup a practical bench demonstration of the use and benefit of this facility, what would I have to do ?
Section 2-13 of the linked Agilent measurement manual talks about the use and theory of Guard terminal. Mostly a method to improve common mode noise rejection for very sensitive measurements. Demostrating it's usefulness would require some kind of external EMI generator and then showing the improvement in measurement with the generator turned on and off both with and without the guard terminal in use.
This app note may be more applicable. It shows several situations where guarding in a multimeter can be useful.
BTW, I Googled "multimeter guard terminal" and found this about halfway down the first page.
If this app note answers your question, consider yourself properly chided. If not - a thousand pardons.
Yes basically, it's a wiring method that helps take better advantage of the common mode differential capability of the instruments differential input amplifier device and circuitry.