Low Filter Roll Off Calculation

[SyncTronX]

abraxalito,

more than that actually, I had to back it down to 5Vpk to get it to be 10Vpk. The simulator show the 2nd one as 20Vpp...not the value that I entered.

This version of NI Multisim is buggy. When they released V14...it has errors. They, NI can't seem to get it fixed. Or maybe I have to use one of the vendors function generators on it.

Seems to work okay with the "Labview" Sig Gen. Imagine that.

 

[abraxalito]

Could be that your FG is 50ohm source impedance and expects 50ohm termination impedance. That would explain why it puts out twice the specified voltage into a high-Z load. The scope traces look right.

 

[SyncTronX]

Let me see if I can change the generator impedance.

Nope I cannot change the impedance of the generator. I tried another gen an Agilent but it only went up to 10 Vp-p and wouldn't trigger the output. I don't know why as the -10Vpp sine should have as it was greater than -9.43 volt point. 50 Ohm load didn't make a difference. Input is still 20Vp!

 

[abraxalito]

Let me see if I can change the generator impedance.

Or you could slap a 50ohm resistor on its output then see if the output voltage is what you expect.

 

[SyncTronX]

Thanks "Brax"

 

[abraxalito]

Ah I think I see a clue in the siggen you're using - it has a balanced output. You're taking the output between the two phases - to halve the output voltage connect 'GND' on the schematic to the centre of those 3 pins (marked 'COM') not the left-most one. I reckon this'll fix it.

 

[SyncTronX]

Sync reckon's the Oracle has words of wisdom he should heed.

 

[SyncTronX]

Derivation

Here was the original question:

 

[rayma]

Here was the original question:

The instructor was wrong, because he did not say find the magnitude of the gain. He just said the value of the gain, which includes the sign. Since the gain is -50, none of the answers are correct.