Activity for Olin Lathrop
| Type | On... | Excerpt | Status | Date |
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| Edit | Post #286614 | Initial revision | — | over 2 years ago |
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A: Mysterious little cases hanging on street wirings in India This is not a direct answer, but a few observations that might be clues. The additional pictures help, but you still haven't answered where this is. The purpose of the question was to get some idea of how formally things are done in your area. This pictures show a mess, hinting at this being s... (more) |
— | over 2 years ago |
| Edit | Post #286595 |
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| Edit | Post #286595 | Initial revision | — | over 2 years ago |
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A: What effect will extreme temperatures have on characteristic impedance of a wire? The expansion of the conductors is the least of your problems. The real issue is the effect of excessive temperature on the insulators. The plastic in the cable has three electrical functions: To insulate the two separate conductors. To provide a specific constant dielectric between the con... (more) |
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| Comment | Post #286589 |
Content is not easily noticed in comments, and can get deleted altogether. (more) |
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| Comment | Post #286589 |
This is an interesting discussion, but not suited for comments. (more) |
— | over 2 years ago |
| Comment | Post #286589 |
The underlying physics is more complicated than strictly voltage-controlled or current-controlled. However, a reasonable physics model is that trying to draw electrons out of the base (NPN example) is a lossy process, since most of the electrons that leave the emitter get swept away to the collector... (more) |
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| Comment | Post #286537 |
Your new picture shows the basic configuration, but not the specs of what you want the circuit to achieve. Is it amplifying a digital signal? Analog? What impedance? Voltage/current range? The picture is also obnoxiously large. Being rude to the volunteers you seek a favor from is not a good wa... (more) |
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| Edit | Post #286538 |
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| Edit | Post #286536 |
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| Comment | Post #286537 |
Show the circuit. The operating point depends on other circuit elements around the transistor. (more) |
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| Edit | Post #286538 | Initial revision | — | over 2 years ago |
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A: Unexpected impedance spike when paralleling capacitors Unfortunately the frequency legend on your graphs are too small to see, so we don't know how the left and right graphs relate to each other. However, what is certainly going on in the left graph is a LC resonance. Again, it would be useful to know where that peak is in relation to the right graph... (more) |
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| Edit | Post #286536 | Initial revision | — | over 2 years ago |
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A: Re model of transistor is the same in 2 different configuration I'm not sure what you mean by the "Re" model, but ultimately the transistor does a certain thing regardless of what label we put on the circuit it is in. For a NPN like you're modeling, you will have base current going into the base and coming out the emitter, and collector current going into the ... (more) |
— | over 2 years ago |
| Edit | Post #286494 |
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| Edit | Post #286494 | Initial revision | — | over 2 years ago |
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A: Thévenins Theorem for Transistor Circuit It seems like you did the reduction to a Thevenin source mostly right, although the final value is a bit off. The original circuit we want to reduce to a Thevenin source is: First we reduce V1, R1, and R2 to a Thevenin source. The resistance is R1//R2, and the voltage is the V1 voltage app... (more) |
— | over 2 years ago |
| Edit | Post #286477 | Initial revision | — | over 2 years ago |
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A: Wish to have comment votes I see that Monica answered your question directly. However, there is another point to keep in mind. Comments are not for content. That was supposedly the case at SE too, but was poorly enforced. We are more strict about that here. Comments therefore shouldn't be important enough to vote on. ... (more) |
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| Edit | Post #286104 |
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| Edit | Post #286314 |
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| Edit | Post #286314 |
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| Edit | Post #286314 |
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| Edit | Post #286314 | Initial revision | — | over 2 years ago |
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A: How do PLCs normally measure 4-20mA current loops? You should not be relying on the internal circuitry of whatever senses the 4-20 mA current. Note that the two implementations you show both use current sense resistors. The only difference is their value. I have designed several current-sense front ends, although none were inside a PLC. The cus... (more) |
— | over 2 years ago |
| Edit | Post #286212 | Initial revision | — | over 2 years ago |
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A: Level shifting of a 3 state logic pin No, a resistor divider is not appropriate, at least not if you want to get all the information from the STAT pin. In addition, that chart in the datasheet is incomplete at best, or downright misleading if you're less charitable. The first problem is that a single signal indicates three possible v... (more) |
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| Comment | Post #286181 |
It would also add an offset error. (more) |
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| Edit | Post #286181 | Initial revision | — | over 2 years ago |
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A: When do I need to put anti-aliasing filter in front of SAR ADC? Since your noise has "unknown characteristics", you should do low pass filtering in analog before the discrete sampling of the A/D. The two parameters that matter are the frequency content of the signal, and the sampling rate. In theory, nothing is lost as long as the sample rate is more than twi... (more) |
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| Edit | Post #286157 |
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| Edit | Post #286157 |
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| Edit | Post #286157 | Initial revision | — | over 2 years ago |
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A: Misuse of mod privilege? It seems your main question is why all the comments to your question about reactance were deleted. I deleted them because they were no longer relevant. They pointed out problems with the question, and explained why it was closed. You then fixed the question, it was reopened, and it has now gotten ... (more) |
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| Edit | Post #286134 | Initial revision | — | over 2 years ago |
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A: Oscilloscope potentially ESD striked If you're really sure the symptom appeared right after the static discharge, then something in the front end of the amplifier may have gotten damaged. However, that sounds rather far fetched. Scopes should have protection against these kind of events. Were all the effected channels connected to so... (more) |
— | over 2 years ago |
| Edit | Post #286112 |
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| Edit | Post #286112 |
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| Edit | Post #286112 | Initial revision | — | over 2 years ago |
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A: Duty cycle of buck-boost converter Nevermind (for now) what Wikipedia or anyone else says. Stop and actually think about it. One problem with the question is that is says "buck-boost" but doesn't otherwise define that. A buck-boost converter generally means that the output can be both above or below the input. There are differen... (more) |
— | over 2 years ago |
| Edit | Post #286104 |
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| Edit | Post #286104 | Initial revision | — | over 2 years ago |
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A: DAC controlled high side current source. It appears you want a positive current source with the following specs: 0 to 28 V compliance range. Up to 100 mA, adjustable via 10 bit or more digital value. 36 V supply is available. The dissipation from a linear pass element is OK. The large headroom at the high end allows for e... (more) |
— | over 2 years ago |
| Comment | Post #286103 |
How accurate must the output current be? If this is driven from a 16 bit D/A, it's a very different problem than if ±2% is good enough.
You need complete specs before even starting a design. There are various topologies, each with different things they are good at. You are getting way ah... (more) |
— | over 2 years ago |
| Comment | Post #286103 |
What's the complete compliance range your current source needs to have. You said the upper end is 36 V, but how close to 0 V must it still work? Also, what supply voltages are available, and don't tell me 36 V is the max. There will always be <i>some</i> drop across the current sense and/or pass e... (more) |
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| Comment | Post #286090 |
By starting out lecturing, you make it difficult to answer any question. Answerers then have to either spend effort dispelling false assertions, or answer but have others think they agree with the false assertions. If you have a question, ask it. Don't try to tell us what "we" do. (more) |
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| Edit | Post #286049 | Question closed | — | over 2 years ago |
| Edit | Post #286032 |
Post edited: Always be clear about something being homework, when it is. |
— | over 2 years ago |