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Re: Cannot delete file
"I understood that simply using "delete" will get the file deleted in two days :-)" It's supposed to work in two seconds! ?Once deleted, it's gone, forever. That's what Yahoo's programmers broke. "Cutting" a file seems to result in it going away after a few days if you don't paste it anywhere ... but we need to see if that still
does that .Yahoo SAYS they are going to fix these bugs when they pop up........ Andy |
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Re: 5V DC to 1Vpp 1kHz sine oscilator
¿ªÔÆÌåÓýI think the problem is not properly enunciated.I doubt very much that the OP needs? a sinewave "varying between 0V to 1V controlled by potantiometer". First, If it goes from 0 to 1 it is not variable, so why a potentiometer? Second, I scratch my head to find an application that really needs that type of signal. It may be correct, but then, before venturing any suggestion, I would like to have the problem exposed more clearly. The actual solution may be very different than anything that has been suggested yet. Le 02/01/2014 16:54, Andy a ¨¦crit?:
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Re: Error in Half-bridge simulation
---In LTspice@..., <hamed_solar@...> wrote: Thanks you for reminder. Please read the groups homepage and lern, how to put files in the temp-directory. ( http://groups.yahoo.com/group/LTspice/files/%20Temp ) Look for you rfile in this directory ad tell us the position and name - notvthe ..f1.grp.yahoofs... position. Yes,? newbies also have to learn, how to upload files, if they expect to get help :-) hws |
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Re: Error in Half-bridge simulation
hamed_solar,
TELL US (in words) where the file is located. It appears you uploaded it somewhere in the [LTspice] group's Files area, but not where you should have put it. ?The only place you should upload files, is into the "Temp" directory. ?I'm not finding it there.
Do not bother pasting the URL here. ?You don't seem to understand, that URL you posted, was a temporary URL that lasts only a few minutes, and probably worked only for you anyway, so it does no good to post either URL here. ?It doesn't tell us where the file is actually located. ?(This is because of how Yahoo Groups's file system work.) Nobody can offer you any help until you first TELL us where the file is.
Andy |
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Re: 5V DC to 1Vpp 1kHz sine oscilator
'ipekogulmus' wrote: ? "I need to generate 1kHz sine wave as output from 5V DC input. Output wave should have peak to peak amplitude varying between 0V to 1V controlled by potantiometer. ? "I implement the circuit given in . I add a changing resistor(1 to 10k) between gnd and output. Lets say that output node TP1. I read 1 kHz sine wave with -1V to 1V amplitude but.. ? "Problem is output voltage ranges between -1V to 1V. But I want it to be 0V to 1V (peak to peak) " Let's see if I understand the problem. ?You want the output voltage to be a sine wave that swings back and forth between 0 V and 1 V. ?That means it has an amplitude of 0.5 V and an offset of 0.5 V. ?Am I right so far? The circuit you referred to is AC-coupled at the output. ?Note the "10n" capacitor before the 10K resistor. ?That capacitor removes whatever DC offset voltage was present on the transistor's collector. ?If you looked at the collector terminal, or if you remove ("short") the 10n capacitor, do you see approximately the kind of signal you want? In the posted circuit, there is no "bleeder" resistor between OUT and GND, so the offset voltage at OUT is undefined and could be any thing. ?If you ran this in LTspice, it would warn you about the missing DC path from OUT to GND. ?It might either refuse to run, or might add its own resistor from OUT to GND to keep the SPICE engine happy. ? Try adding a resistor between OUT and some positive voltage. ?Maybe this would give you the desired signal. ?If OUT currently swings back and forth between -1 V and +1 V, then connect that resistor to +1 V DC, and then OUT should swing between 0 V and +2 V. ? "I tried to add DC offset using LT1001 inverter op amp. Lets say output of op amp is TP2. I get 3.87V to 3.88V sine wave in TP2 now. I lost the peak to peak voltage." You probably did something wrong. ?Maybe you didn't add power voltages to the LT1001? Why don't you upload the circuit(s) you are trying to simulate, then we can look at it and see what the problem is? ?Instructions, as always, are on this group's main webpage. Regards, Andy |
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Re: 5V DC to 1Vpp 1kHz sine oscilator
John Woodgate
In message <la3rok+1614g9m@...>, dated Thu, 2 Jan 2014,
ipekogulmus@... writes: I need to generate 1kHz?sine wave as output from 5V DC input. OutputYou do not need another op-amp. Since your output is AC-coupled (by 10 nF), all you need to do to get the offset is to add another 10 k to ground across the 100 nF and an 82 k from OUT to +9 V. The effect is also to halve the output voltage (10 k series, 10 k shunt), which you want. You would do MUCH better to upload your schematic (and any other files required to run the simulation) to Files => Temp on the list's web site. Both the oscillator part and the filter part could be improved. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: 5V DC to 1Vpp 1kHz sine oscilator
¿ªÔÆÌåÓýHi ipekogulmus. ? Use a single rail op. Amp.?with output centred at 2.5V DC.? That should do the trick. Note that it will be very difficult to get your op. amp to swing its output to an absolute 0V; otherwise you could bias the o/p at? 1V and swing from 0V to 2V. ? Michael ? From: ipekogulmus@... To: LTspice@... Date: Thu, 2 Jan 2014 06:06:12 -0800 Subject: [LTspice] 5V DC to 1Vpp 1kHz sine oscilator ?
I need to generate 1kHz?sine wave as output from 5V DC input. Output wave should have peak to peak amplitude varying between 0V to 1V controlled by potantiometer.
I implement the circuit given in?. I add a changing resistor(1 to 10k) between gnd and output. Lets say that output node TP1. I read 1 kHz sine wave with -1V to 1V amplitude but..
Problem is output voltage ranges between -1V to 1V. But I want it to be 0V to 1V (peak to peak)?
I tried to add DC offset using LT1001 inverter op amp. Lets say output of op amp is TP2. I get 3.87V to 3.88V sine wave in TP2 now. I lost the peak to peak voltage. Also adding new components changed the total empedance of the circuit. Hence output of TP1 is also changed.?
Can anybody offer me a solution?
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5V DC to 1Vpp 1kHz sine oscilator
I need to generate 1kHz?sine wave as output from 5V DC input. Output wave should have peak to peak amplitude varying between 0V to 1V controlled by potantiometer.
I implement the circuit given in?. I add a changing resistor(1 to 10k) between gnd and output. Lets say that output node TP1. I read 1 kHz sine wave with -1V to 1V amplitude but.. Problem is output voltage ranges between -1V to 1V. But I want it to be 0V to 1V (peak to peak)? I tried to add DC offset using LT1001 inverter op amp. Lets say output of op amp is TP2. I get 3.87V to 3.88V sine wave in TP2 now. I lost the peak to peak voltage. Also adding new components changed the total empedance of the circuit. Hence output of TP1 is also changed.? Can anybody offer me a solution? |
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Re: Error in Half-bridge simulation
John Woodgate
In message <la3jr3+f0eg9c@...>, dated Thu, 2 Jan 2014, hamed_solar@... writes:
I design this circuit that attach to this post.Attachments are not permitted, and the URL you gave is useless after a minute or so. You should upload your schematic and other files essential to run the simulation to Files => Temp. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Error in Half-bridge simulation
Hi
I design this circuit that attach to this post. The line voltage is about 100 volts. It has two mosfet for switching line voltage at about 100 khz frequency. There is two voltage source for pulse generation(Gate driver). The output of this bridge must switch 100 volts but it only switches 16 volts. It has enough dead time for prohibiting of short circuit occurance . What is a problem ? How can I correct this? Regards . |
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Re: charge amplifier using OPA129; but, imported model (OPA129) doesn't work correctly.
The added offset voltage source moves the op-amp's inverting input pin up or down, which varies the current through resistor Rs.
0.748 mV (0.747 mV + 0.936 uV) across 50 Megohms is about 15 pA, which essentially cancels the bias current that seems to flow out of the op-amp model's input pin.
The added voltage source doesn't really fix the offset voltage. ?It makes it 1000 times larger.
Andy |
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Re: charge amplifier using OPA129; but, imported model (OPA129) doesn't work correctly.
Thank you, Helmut and Andy.
It seems to me that the TI's SPICE model is more realistic than LT's built-in opamp models, in terms of input bias current and input offset voltage. Your schematic (photoamp_opa129.zip) works perfectly as I expected. I think the single component of the voltage source (0.747mV) that you added compensates both the effects (input bias current and input offset voltage). As I understand, the input bias current gives linearly ramping (up or down) voltage with time to Vout, and the input offset voltage gives just voltage offset (constant with time) to Vout. It is not difficult for me to understand that the input offset voltage could be compensated by the added voltage source, but the input bias current effect? Could you give me an explanation of how the added voltage can compensate the input bias current? Best regards, Seongchong |
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Re: Cannot delete file
As long as the flashy animations work, I don't know why anyone would want functionality. It's not like it did work before, did it? Maybe I shouldn't be this sarcastic, but the impression that leaves on me is that the general goal is to make things prettier, not functional, as if all users are children who get bored from a year to another by the way things are presented. Maybe it's just me. Vlad |
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Re: Questions to LTC1043 model / SPDT switches
Hello Thomas,
Please take a look to this example. Files > Examples > Apps > http://groups.yahoo.com/neo/groups/LTspice/files/%20Examples/Apps/ I did this example when we had a similar requirement. http://groups.yahoo.com/neo/groups/LTspice/conversations/topics/27506 Best regards, Helmut |
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