1. The problem statement, all variables and given/known data

So in the future, I will have to find out what is inside a black box:

A Black Box is actually a grey metal box with two terminals sticking out of it. Inside are two passive components, one is a resistor and the other may be a capacitor or an inductor, and they way they are connected may be either in series or in parallel. The point of the test is to use a multimeter, a function generator, and an oscilloscope to determine what components are inside, how they are connected, and their values, to within about 10%. There are four possible cases; RC-series, RC-parallel, RL-series and RL-parallel.

2. Relevant equations



3. The attempt at a solution

Here is the solution to it: http://drunkenengineer.tripod.com/Year1/ele202/blackbox/blackbox.html

The issue is that I'm having trouble understanding why the guide uses those techniques/tests.

I understand the ohmmeter test. The reason why the ohmmeter would give a reading of infinity if it is a rc-series box is because capacitors act as open circuits to DC.

Questions:

1. Phase Shift Test: we have to make a circuit. It consists of a signal generator, an oscilloscope, a black box, and the attached symbol. The attached symbol is just a signal generator, right? And functions generators are the same as signal generators, right? The shape of the circuit looks weird. What is the motive behind the circuit designed like this?
2. Inductor test: I don't understand the circuit diagram. A and B are two different channels, right? So where would the other ends of the channels be connected? What is the motive behind the circuit designed like this?

 

Look up the term "Lissajous" for more information.