How to use BNC tees properly?

[technix]

I bought a few BNC tees so I can tap off the output of my function generator directly, along with a few 30 centimeter BNC patch cables. How should I use it?

* Mode 1: attach the bottom of the tee to the output jack of the function generator, and attach the output connectors (BNC or alligator clips) and the patch cable leading to oscilloscope input to the arms.
* Mode 2: attach the bottom of the tee to the input jack on the oscilloscope, the patch cable from the function generator comes in on one arm, and the output lead goes to the other arm.

Also is this an approximate of a network analyzer?

[HB9EVI]

it depends. if you work in 50 ohm impedance system, both sides of the cable have to be properly terminated.

I would set it up like the cable without tee on the signal source, the tee on the scope, one end in direction of the signal generator, the other end with the lead to dut.

[bigsky]

it depends. if you work in 50 ohm impedance system, both sides of the cable have to be properly terminated.

If you split a signal with a T piece and terminate both sides with 50 ohms, the source drives into a 25 ohm load, which is probably not what you want!

[David Hess]

* Mode 1: attach the bottom of the tee to the output jack of the function generator, and attach the output connectors (BNC or alligator clips) and the patch cable leading to oscilloscope input to the arms.

This works fine at lower frequencies.

* Mode 2: attach the bottom of the tee to the input jack on the oscilloscope, the patch cable from the function generator comes in on one arm, and the output lead goes to the other arm.

This way also works at high frequencies where a 50 ohm termination is used at the output end and the high impedance input of the oscilloscope is attached in the middle using the BNC-T.

Also is this an approximate of a network analyzer?

It can be used that way but it is better to apply the function generator output to the DUT (device under test), and use two oscilloscope probes to sample the input and output.  The function generator's trigger output can be attached to the oscilloscope's external trigger.

[HB9EVI]

it depends. if you work in 50 ohm impedance system, both sides of the cable have to be properly terminated.

If you split a signal with a T piece and terminate both sides with 50 ohms, the source drives into a 25 ohm load, which is probably not what you want!

this is not what I meant. When I say both sides, I mean - source and load.