"Jeffrey Angus"

Phil's still right.


** Course he is....


Yes they show an isolation transformer. But they show it isolating
the scope, NOT the device being tested.

There's no mention of using an isolation transformer to float the
device being tested.

Tek's app note is based on NOT being able to isolate the device
being tested.


** Tek are very remiss in not mentioning the MOST COMMON method of using a
scope on non mains isolated circuitry - which is to install a 1:1 mains
isolation tranny and then ground any part of the circuit you need to.

What this achieves is ELIMINATING the need to make floating measurements.

Similarly, even with equipment that has mains isolation by virtue of a 50/60
Hz transformer - one can temporarily disconnect the secondary side from
supply ground and float the circuitry. This again allows you to ground any
part of the circuit you desire to facilitate scope measurements.




.... Phil