Oscilloscope, bread board set up, measuring phase / gain etc.

[js6]

Homework Statement

Hi,

I've been having trouble setting up an oscilloscope, with a AC voltage supply, to a breadbox, with a "black box" in the circuit. the black box is just a set of 3 pairs of terminals, each a "unknown component" such as a diode, capacitor, resistor, etc.

Basically I need to figure out how to properly construct the circuit to obtain values for phase, peak-peak voltage, etc using the oscilloscope, which would then allow me to determine the components. (Where to plug things in, such as the Ch.1 / Ch.2 of the oscilloscope, and the output of the AC voltage, with the board and the box.)

I was wondering if anyone has a diagram, or picture of such a set up that could help me, my attempts have been fairly basic, and encounter problems such as the grounding?

Thanks

 

[berkeman]

Homework Statement

Hi,

I've been having trouble setting up an oscilloscope, with a AC voltage supply, to a breadbox, with a "black box" in the circuit. the black box is just a set of 3 pairs of terminals, each a "unknown component" such as a diode, capacitor, resistor, etc.

Basically I need to figure out how to properly construct the circuit to obtain values for phase, peak-peak voltage, etc using the oscilloscope, which would then allow me to determine the components. (Where to plug things in, such as the Ch.1 / Ch.2 of the oscilloscope, and the output of the AC voltage, with the board and the box.)

I was wondering if anyone has a diagram, or picture of such a set up that could help me, my attempts have been fairly basic, and encounter problems such as the grounding?

Thanks

Welcome to the PF.

So can you say more about these black boxes? Are the 3 contacts basically the input, ground and output? And you are tasked with determining the transfer function Vout/Vin, and modeling it with discrete components?

Except for the diodes part, this is what the transfer function measurement does with impedance analyzers like the HP 4194. It has a swept AC excitation source, and a monitoring port that measures the transfer function (amplitude and phase) versus frequency. That is basically what you need to do manually with your signal generator and oscilloscope.

 

[nsaspook]

I think you are looking for a 'curve tracer' circuit. This is a simple "Octopus".
http://www.youtube.com/watch?feature=player_embedded&v=Gwo3pEH7hUE#

http://www.syscompdesign.com/AppNotes/curve-tracer.pdf

 

[js6]

Thanks for the replies,

The black box is just basic 2 terminals for each component, and yes I have to measure the gain (Vout/Vin) of the voltage drop over each unknown component, and other things such as phase. I understand what to expect from each component, however my problem lies in the actual set-up of the osscilloscope / AC generator / black box system,

I'll attach some pictures to show what I think I'll have to do, maybe someone can confirm the diagram is correct? Like I said, I understand what to expect from theory, it's just how to set-up the equipment with one another is my problem,

EDIT: Also, maybe if someone can clarify the exact purpose of the extra resistor, which would help a lot

Thanks again,