can anyone tell what I did wrong here? my goal is to measure current using an opamp, I need to be able to measure positive and...

can anyone tell what I did wrong here? my goal is to measure current using an opamp, I need to be able to measure positive and negative current, and I have these LTC2053 OpAmps available, but I'm trying to simulate what I'm thinking about doing in LTspice and I can't get any output at all.... I need to be able to see from 50uA to .1mA, which is a pretty big range (and I need this in positive...

Gents, Does anyone know where to find the SPICE model for the NE3509? Or at least one that's close enough for pulse stuff? CEL only has the...

Gents, Does anyone know where to find the SPICE model for the NE3509? Or at least one that's close enough for pulse stuff? CEL only has the usual microwave models but I want to use it as a fast low capacitance switch and simulate in LTSpice. -- Regards, Joerg http://www.analogconsultants.com/

See ADCMP551_4LT.zip on the Device Models & Subcircuits page of my website. Sort of a SWAG, TC's not modeled, but should be suitable for...

See ADCMP551_4LT.zip on the Device Models & Subcircuits page of my website. Sort of a SWAG, TC's not modeled, but should be suitable for system analysis. Please try it out and let me know if it works to your satisfaction. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations ...

I decided to delve deeper into the mystery. Here is an .asc file of the strange circuit previously under...

I decided to delve deeper into the mystery. Here is an .asc file of the strange circuit previously under discussion. https://app.box.com/s/cwlnjt5zh14ubdaul4odvhcehw2tnapa Unless I have made an error, it appears to be non-functional. I am now preparing a bonfire for my collection of such old documents. Robert Miller

Got it installed with wine here on my PC. Fonts are a bit wonky, but that happens from time to time, so not going to really bother with...

Got it installed with wine here on my PC. Fonts are a bit wonky, but that happens from time to time, so not going to really bother with it. Took things for a spin by trying to build your basic low-pass filter as one might see on a momentary-contact button (etc.). Thing is, I wasn't seeing any "switch" or "button" type symbols -- am I just blind, and missed them somewhere in the myriad ...

I'm using this circuit to provide 250V pulses to an ignition coil. https://www.dropbox.com/s/1w33uss3eedem05/ignition2.pdf?dl=0 The IC is a...

I'm using this circuit to provide 250V pulses to an ignition coil. https://www.dropbox.com/s/1w33uss3eedem05/ignition2.pdf?dl=0 The IC is a Linear Technology LT1243. 12V is provided on G$1 to the left. G$2 accepts a trigger pulse, and G$3 is ground. LTSpice says that this works, and indeed the real implementation does. Mostly. The difference is that after the circuit has been tr...

I can't believe the difficulties I have sometimes with this tool. So much of it is counter intuitive and even dysfunctional. I just when through...

I can't believe the difficulties I have sometimes with this tool. So much of it is counter intuitive and even dysfunctional. I just when through an hour or two trying to change a model connected to a FET. Turns out that saving a matching symbol under the new name and editing the library file name in the symbol attributes doesn't cut it. The symbol in the schematic has attributes

Last of the Japanese/German-made business-class machines; several years old now but AFAIK they're well-built and not a PITA to work on,...

Last of the Japanese/German-made business-class machines; several years old now but AFAIK they're well-built and not a PITA to work on, and even a refurb should be good for a few more years of service...

I picked up the macromodel from AD(TI) for this IC. I=20 am using the manual to try to figure out how to=20 incorporate the model in a...

I picked up the macromodel from AD(TI) for this IC. I=20 am using the manual to try to figure out how to=20 incorporate the model in a circuit idea, but i hit up=20 against errors. This one has me baffled though. =20 The error i am getting is: "Port(pin) count mismatch between the definition of 'ad734.cir' and = instance xu1. The instance has more connections than the definition." ...

See AD790_JT.zip on the Device Models & Subcircuits Page of my website: Behavioral model based on the datasheet only. Comments most...

See AD790_JT.zip on the Device Models & Subcircuits Page of my website: Behavioral model based on the datasheet only. Comments most welcome. Please report any issues. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations |

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and...

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and BC557B): https://upload.wikimedia.org/wikipedia/commons/9/9f/PUT_LED_blinker.png Nothing wants to oscillate. Looking for a bug I have also tried the simplest possible neon lamp oscillator (with Vstrike=100V, Vhold=50V, R=220k, C=1u), but there are no scillations either: ...

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 ...

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

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

"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

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

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...

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...

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...

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...