BUT, what are those “easily measured or calculated parameters”? I am a circuit designer and have no idea what they are (or how to do the measurements)!. I strongly suspect that I am not alone. How about a tutorial for the wiki?

Jim

On Apr 29, 2023, at 11:06 AM, John Woodgate <jmw@...> wrote:

Many types of transformer do not need complicated models like Gummel-Poon for transistors, but of course complicated models like Chan can give more accurate results (often more accurate than is necessary, but that also apples to transistor models, which do not account for variations between samples). Simple models can use easily measured or calculated parameters, so it is easy to relate the model to the hardware.

Please note the new Subject line.

======================================================================================
Best wishes John Woodgate OOO-Own Opinions Only

Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi (340 - 245 BC)

On 2023-04-29 18:02, Jim Wagner wrote:

For me. the real transformer challenge is associating the physical parameters (dimensions, numbers of turns, core material, and such) into model parameters. One might reasonably assert that this is no different than, say, transistors. There is a big difference, though; I can build a transformer but I am not likely to build a transistor. I do not have the capability to measure transistors sufficiently to create models, so must rely on third-parties to do that. What third party do I use for that ferrite toroid transformer that i just built?

Perhaps the solution to this is a transformer model generator (like VDMOS tool). I can handle program writing but I do not know enough about magnetics to even think about something like that. To be useful, such a model generator should rely on measurements the most of us could do in a modestly equipped lab (say, with a signal generator and an oscilloscope).?

Jim Wagner

Oregon Research Electronics

On Apr 29, 2023, at 9:38 AM, Andy I <AI.egrps+io@...> wrote:

Susan wrote, "My big issue/stumbling-block when using 'spice simulators is transformer models; they all seem to be described in intractable terms making it difficult to translate something I have in my hand to an accurate simulation model."

That sounds like a topic for a separate subject (not this one).? The simplest transformer models are very simple.? It's the more complicated ones that can be challenging.

Andy

1. Define the primary inductance as a parameter Lp
2. Change the value of the primary inductor to {Lp}. the curly braces will pick up the value of parameter Lp
3. Define parameter n to be the turns ratio.
4. Set the secondary inductance to be {n*n*Lp}

hello sir, how can i set the total winding in trafo simulation? (flyback transformer)

hello sir, how can i set the total winding in trafo simulation? (flyback transformer)

I didn’t follow the discussion, but allow me to throw in that input protection against HF-transients like electrostatic discharge ?sparks“ often can be achieved by ferrite beads put in serial into the input line.

—

Christoph

Am 18.07.2023 um 05:49 schrieb Tom via <tomhajjar@...>:

Neon bulbs can be used for receiver or audio amplifier input protection, modem input protection...etc. Neon bulbs?cannot handle the power a ceramic gas tube protector or varistor provides but they have similar capacitance to a ceramic gas tube. Varistors have very high capacitance and are not suitable for RF without say a series choke. The phone/DSL line to your house has a differential ceramic gas tube protector mounted in the NID box provided by the phone company.?

One has to define what surge event could be expected. For an RF receiver/audio amp, one could expect static buildup or discharge by the user or a surge induced into the feedline by a nearby lightning hit. In general a direct lightning hit will destroy almost anything. Goal should be to isolate the damage to a replaceable PCB/module or to an external surge protector.?

Am 18.07.2023 um 05:49 schrieb Tom via <tomhajjar@...>:

Neon bulbs can be used for receiver or audio amplifier input protection, modem input protection...etc. Neon bulbs?cannot handle the power a ceramic gas tube protector or varistor provides but they have similar capacitance to a ceramic gas tube. Varistors have very high capacitance and are not suitable for RF without say a series choke. The phone/DSL line to your house has a differential ceramic gas tube protector mounted in the NID box provided by the phone company.?

One has to define what surge event could be expected. For an RF receiver/audio amp, one could expect static buildup or discharge by the user or a surge induced into the feedline by a nearby lightning hit. In general a direct lightning hit will destroy almost anything. Goal should be to isolate the damage to a replaceable PCB/module or to an external surge protector.?

Thank you Andy. I truly appreciate all of your help. I was able to find an opamp that meets my environmental requirements. However the response seems to be nonlinear.

Here is the circuit

I commented out the unnecessary simulation directives and adjusted the amplitude of the pulse to match the photodiode I selected so you will notice some changes there.

Those run-time node and net numbers can vary from run to run, especially after adding a component. AFIK, they are not known until the sim runs.

Jim, Oregon Research Electronics

On Jul 17, 2023, at 12:33 PM, Chris - G0LOJ <chrisbudd606@...> wrote:

I believe that nodes (or nets) can be user-named, and that curves on an LTSpice plot can also be user-named, but sometimes it would be simplest to use the node numbers assigned by the software during the building of a schematic. Is there a way to cause those node numbers to be displayed on the schematic. Thanks, Chris.

On Jul 17, 2023, at 1:10 PM, Dan via <danniejackson@...> wrote:

You can lable the nets with numbers or letters.? As for them showing up as you mentioned I am not sure about that.