When can the oscilloscopes internal resistance be ignored Wh

When can the oscilloscope\'s internal resistance be ignored? When can the function generator\'s output resistance be ignored?

Solution

An oscilloscope is basically a load , that is the output from any circuit can be fed as input to the oscilloscope. The internal resistance of the oscilloscope is seen as load to the circuit. And this load appears in parallel to the circuit. When resistances are in parallel the higher value can be neglected. Hence if the internal resistance of the oscilloscope is very large then it can be neglected. It is in the order of Mega Ohms.

Similarly the function generator acts like a source, it\'s resistance appears in serial to it. When resistances are in series the one with the least value can be neglected. Hence the resistance of the generator can be neglected if it is very small. Generally it is in the order of few tens of Ohms.