The term "OpAmp" is misused by me. TI and AD use Amplifier. They make multiple types designed to feed differential ADCs and almost all rely on external resistors to sett gain.  Gain is dependent on

It's not quite the same as your schematic, but I uploaded an autotransformer model <https://groups.io/g/LTspice/files/z_groups.io/Files-sorted-by-message-number/msg_ZZZZZZ/Variac_Test.zip> earlier

I’ll update it tomorrow; getting late here. I got answers to most of my issues, so it may be a useful stating point. Dave Sent: Friday, December 27, 2024 8:01 PM To: ltspice@groups.io Subject:

DaveGreat job 👏 I  will look at it.

Andy, I’m away from my library now so I can’t consult dusty sources, but the idea of polarity indifference for infinite gain amplifiers is illustrated in the technique using “stamps” or

It would make an ideal "Ideal Rectifier" ... gmail.com@groups.io> wrote:

This is not true. In the bottom inductor you have all the magnetizing current (about 7A), but in the top inductors there is almost no current, because there is a negligible load. In a typical

Jeff, that is an interesting description and is new to me.  But the part that most puzzles me is this one: It seems that the polarity should matter.  I get it that the differential input voltage

Loads were resistive, from the taps points to return. Sent: Thursday, December 26, 2024 4:14 PM To: LTspice@groups.io Subject: EXTERNAL: Re: [LTspice] Autotransformer deep questions!

You are still struggling with a complicated transformer. Start with a simple winding with just one tap, with the mains supply across the whole winding, and no separate 'secondary' winding. When you

Don't even bother with the one that is physically impossible.  It doesn't matter if it simulates - it is wrong! Where are the loads connected? Andy

I later extended the TRAN to over 1 second, then starting data at 1s. The currents definitely took 6-8 cycles to settle down, but voltages were essentially the same. “But there is zero coupling

Several more things to note: It is never a good idea to simulate for only 1/2 of a cycle, or even 1 cycle - *especially* when inductors are involved!  A far better thing to do is to simulate for 10s

Dave, Start your sinewave source ( V1 ) at some phase angle. 10, 20 ... 90 degree should resolve the loading issue. With 10 degrees, I have a 10 ohm load at node F and a clear sinewave. Mike

The ideal fully differential amplifier is another description of a theoretical device called the nullor. A nullor has two ports: one port, has zero conductance, zero voltage across its terminals, and

Ahh, unloaded, so (little to) no reflected impedance! In this simplified circuit, L2 is on top of L1, and is the 220V input, so the same current flows in L1. I tried loading the (buck, 210V) tap

Impedance of a 100mH inductor at 50Hz=31 ohms 220V into 31 ohms= about 7 amps

Same readings, within cursor positioning tolerance… Also extended the .tran until current transient decayed, around 60+ms. I plotted the currents in L1 and L2: Essentially identical , but + and –

Use the cursor instead of MEAS statements, which are so easily wrongly-written.

.TRAN for 1010ms made no difference; same measurements at 1005m as at 5m Sent: Thursday, December 26, 2024 2:04 PM To: LTspice@groups.io Subject: EXTERNAL: Re: [LTspice] Autotransformer deep