Injecting a bit of chaos into your day -- Chua's circuit

Started by Tim Wescott in sci.electronics.design6 years ago 33 replies

Diddling with things for possible future videos. I think I can make an example of a Chua's circuit using a motor with attached pendulum for the...

Diddling with things for possible future videos. I think I can make an example of a Chua's circuit using a motor with attached pendulum for the tank -- hence the oddball component values. Shove it into LTSpice, run it, and you should see some classical chaotic behavior. Here's a pic of the phase-plane; the axes are labeled, although you may have to squint to see them. https://drive...


Spice Oddity

Started by Syd Rumpo in sci.electronics.design6 years ago 14 replies

Hi I have a line driver circuit in LTspice simulation. It's a bridge circuit with op-amps and bipolars with a neat well-defined quiescent...

Hi I have a line driver circuit in LTspice simulation. It's a bridge circuit with op-amps and bipolars with a neat well-defined quiescent current. Sadly, I can't show the design, but I'm sure it's not original. The frequency range is 10kHz to 80kHz. So, I do a transient sim with a sinusoidal source stepping from 10kHz to 80kHz and all is good. Not flat, but within a dB. Then I d...


OT: Dealing with random laptop lockups

Started by bitrex in sci.electronics.design6 years ago 94 replies

I have an Acer Aspire E15 laptop that I use for running LTSpice and doing various business-related tasks. Unfortunately, over the past few...

I have an Acer Aspire E15 laptop that I use for running LTSpice and doing various business-related tasks. Unfortunately, over the past few weeks or so it's started to randomly lock up completely on a daily basis - no blue screen, just totally frozen and unresponsive. I've tried resetting Windows 8.1 to its factory condition, updating the BIOS, and installing the latest wireless and chi...


Howland current pump question

Started by bitrex in sci.electronics.design7 years ago 28 replies

Is it normal for the op amp inputs of the Howland pump to not be at the same voltage? In all my experiments in LTSPICE with the "improved"...

Is it normal for the op amp inputs of the Howland pump to not be at the same voltage? In all my experiments in LTSPICE with the "improved" topology and grounded resistive loads, this seems to have been the case. The circuit obviously has both positive and negative feedback, but if the opamp output is not railed then I assume the negative feedback must be "winning." But if this is ...


What software packages do you use for RF design?

Started by bitrex in sci.electronics.design10 years ago 5 replies

What software do the folks here that do RF design work (UHF/microwave) use for CAD/simulation purposes? ADS seems to be an industry...

What software do the folks here that do RF design work (UHF/microwave) use for CAD/simulation purposes? ADS seems to be an industry standard, but definitely not in the budget for me. LTSpice is great and free, but doesn't seem to support things like design and analysis using Y/S parameters, stability factor calculation, noise circles, that sort of thing. Is there other software th...


Uart through an audio transformer

Started by Martin Griffith in sci.electronics.design13 years ago 27 replies

Any rules of thumb about sending a 9600 baud UARTsignal ,from an 8051 through a telecom type V90 audio transformer, (LT spice K L1 L2 1 @ 4mH Rs...

Any rules of thumb about sending a 9600 baud UARTsignal ,from an 8051 through a telecom type V90 audio transformer, (LT spice K L1 L2 1 @ 4mH Rs = 10R) I only need about 8 bytes of data, and LTspice seems to need a square wave for about a millisecond before it settles down. So a long sync word of 010101 etc then a start byte? I'll pad the sig down to 100mV or so martin


New Improved +/-45V PSU

Started by Harry D in sci.electronics.design8 years ago 37 replies

Here is my 2W +/-45V PSU http://kvisit.com/S_KuKAw See the MSD7342-224ml for coupled inductor. The IRF9640 is overkill but only SC3...

Here is my 2W +/-45V PSU http://kvisit.com/S_KuKAw See the MSD7342-224ml for coupled inductor. The IRF9640 is overkill but only SC3 model available. The control loop should be pretty straight forward. What is the input voltage range desired? I would copy in that neat net + wiring list that you guys use but do not know how. Just learning LTSPICE. Cheers, Harry


Re: LTspice question: modelling a solenoid

Started by Phil Allison in sci.electronics.design13 years ago 23 replies

"John Nagle" > I need to model the "selector magnet" of a Model 15 Teletype. > This is an electromagnet with an iron core. > DC...

"John Nagle" > I need to model the "selector magnet" of a Model 15 Teletype. > This is an electromagnet with an iron core. > DC resistance is 55 ohms. Inductance is 4 Henries. ** How did yo get that 4H figure?? Iron core solenoids are not pure inductors - they are "lossy inductors" with phase angles of about 45 degrees. ... Phil


Microcap is now free

Started by boB in sci.electronics.design2 years ago 6 replies

...

http://www.spectrum-soft.com/download/download.shtm https://www.eevblog.com/forum/projects/microcap-12-is-free-(as-in-beer)-now/msg2596968/?topicsee n#msg2596968 I used to use verion 5 I think it was until LTspice came along...


LT Parts to Stock Lab - Recommendations

Started by Anonymous in sci.electronics.design7 years ago 3 replies

I have been using LTSpice and would like to have on hand a selection of LT parts. The type of circuits I build relate to signal...

I have been using LTSpice and would like to have on hand a selection of LT parts. The type of circuits I build relate to signal generation, amplification and processing; all analog and in the range of DC to 100KHz. I generally operate them on either 4 x AA cells, or a 12VDC 1A plug pack, prefering single rail. I would like to stock parts that have a broad range of uses, so as not t...


LTSpice question

Started by billbowden in sci.electronics.design5 years ago 13 replies

I would like to determine the overall response of a LC circuit where the L value is stepped and the C value is stepped for each L value and the...

I would like to determine the overall response of a LC circuit where the L value is stepped and the C value is stepped for each L value and the overall response is displayed in dB.. In Basic it would be: For L= 1 to 100 step 10 For C=1 to 100 step 10 Print response next C next L Any idea how to do that? .


Diode (LED) parameters in LTSpice

Started by John S in sci.electronics.design4 years ago 3 replies

This is the model I'm using: .model LXHL-BW02 D(Is=4.5e-20 Rs=.85 N=2.6 Cjo=1.18n Xti=200 Iave=400mA Vpk=5 mfg=Lumileds type=LED) It is...

This is the model I'm using: .model LXHL-BW02 D(Is=4.5e-20 Rs=.85 N=2.6 Cjo=1.18n Xti=200 Iave=400mA Vpk=5 mfg=Lumileds type=LED) It is the closest selection of Vf to the diode I'm going to use. However it is a bit higher than the spec sheet. How do I adjust the parameters above to get a lower Vf? Thanks, Guys. JohnS


LTSpice: How do make a Schmitt oscillator run?

Started by Joerg in sci.electronics.design13 years ago 8 replies

Ok, simple circuit: Schmitt inverter, 10K resistor from output to input, 1000pF capacitor from input to ground. Vh set to about 20% of Vhigh....

Ok, simple circuit: Schmitt inverter, 10K resistor from output to input, 1000pF capacitor from input to ground. Vh set to about 20% of Vhigh. Should happily oscillate but I get the error message "Time step too small". Also there is a noted dip in voltage down to about 80%, something which should even be possible with a digital behavioral device. What gives? How can I fix that and make i...


Two questions about LTSpice

Started by Marco Trapanese in sci.electronics.design9 years ago 23 replies

Guys, I know most of you are experienced users of spice here :) Two short questions, I've already RTM without find the answers. - I need a TIP...

Guys, I know most of you are experienced users of spice here :) Two short questions, I've already RTM without find the answers. - I need a TIP 122 model... where I should look for? - worst-case scenario: I set the tolerances of my resistors. How to run a simulation to get the worst-case? I'm talking about the maximum span of selected traces when components reach their end values. Tha...


Pinging 74HC4046 Users

Started by Jim Thompson in sci.electronics.design9 years ago 96 replies

Finally zeroing in on modeling the 74HC4046 after finding a unpublished AppNote that gave more details on the innards. This is what a fixed...

Finally zeroing in on modeling the 74HC4046 after finding a unpublished AppNote that gave more details on the innards. This is what a fixed frequency looks like, simulation-wise... http://www.analog-innovations.com/SED/HC4046_VCO_2_SIM.pdf Comments? Scalings? (This is based on AppNote and Datasheets claiming trip at VDD/2). First release will be VCO only and will be in LTspice forma...


LTSpice: how to simulate a current limiter?

Started by Piotr Wyderski in sci.electronics.design3 years ago 7 replies

Hello, in my sims I often need to simulate a soft-saturable current limiter, usually for AC. The exact construction of such a limiter is not...

Hello, in my sims I often need to simulate a soft-saturable current limiter, usually for AC. The exact construction of such a limiter is not important from the core circuit's perspective. As long as its I(U) is sigmoid or arctan-like, it's fine. What's the simplest way to express such a building block in Spice? Making it out of discretes every time adds considerable obscurity to the sim a...


LT3080 0 to 3 V variable voltage regulator circuit

Started by Anonymous in sci.electronics.design8 years ago 3 replies

Hello all. I am having some trouble figuring out how to use the LT3080. I d= idn't see any circuit examples that looked like what I wanted to do....

Hello all. I am having some trouble figuring out how to use the LT3080. I d= idn't see any circuit examples that looked like what I wanted to do. I have= simulated a circuit in LTSpice but I can't quite get it to act the way tha= t I expect it to. I want to supply a variable voltage from 0-3VDC with the highest stable cur= rent possible. I don't know what voltages to use for IN and ctrl an...


Critic My Ltspice Model

Started by amdx in sci.electronics.design10 years ago 8 replies

Sorry if this is a repost, I didn't see my first post. I'm looking for constructive criticism to create a better model and help me with...

Sorry if this is a repost, I didn't see my first post. I'm looking for constructive criticism to create a better model and help me with the concept I present about the stray capacitance. The concept: the stray capacitance doesn't lower the input impedance it just adds to the resonating capacitor, changing the resonant frequency. The 100meg is supposed to isolate the power supply. (n...


Faux MOSFET... Behavioral Modeling

Started by Jim Thompson in sci.electronics.design8 years ago 5 replies

For sometime now I have been trying to build a behavioral model of logic gates that was consistent with real-world behavior when mixed into an...

For sometime now I have been trying to build a behavioral model of logic gates that was consistent with real-world behavior when mixed into an Analog environment. (Existing logic models, such as those in PSpice and LTspice are state machines and do not behave properly when used for Analog applications, such as when you build a crystal oscillator around a 74HCU04.) So I now invite you to ...


LTSpice Help

Started by OldGuy in sci.electronics.design8 years ago 23 replies

I am new to Spice as well as LT Spice. I have input most of my circuit after spending much time looking for components. I have not run the...

I am new to Spice as well as LT Spice. I have input most of my circuit after spending much time looking for components. I have not run the circuit yet since I have a hole where a unijunction goes. The circuit additionally uses a triac, scr and transistor. I found the *Programable Unijunction Transistor pkg: TO-226AA .SUBCKT X2N6027 1 2 3 for a "generic" (to me) unijunction. B...