Activity for Olin Lathropâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #286793 |
I was referring to the opamp by itself. An ideal opamp in this case will have zero output impedance. I didn't mean that the zero output impedance is ideal for the rest of the circuit. In fact, I even pointed out how the inductor across the output is pointless in this circuit because the output of ... (more) |
— | over 2 years ago |
| Comment | Post #286793 |
Oops. I meant to say high pass. Fixed. It should be doable without the resistor on the output of the oscillator. The right LC network can use the fixed input impedance of the inverting amplifier to control Q.
I'm not sure the OP is ready for these details yet. I haven't seen any evidence that ... (more) |
— | over 2 years ago |
| Edit | Post #286793 |
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— | over 2 years ago |
| Comment | Post #286792 |
You have been told this before. Use junction dots to show what intersecting schematic lines connect and which don't. For example, in the right diagram we can't tell whether only the bottom of L1 is connected to ground, or whether R1 and L2 also are. This is your last warning. (more) |
— | over 2 years ago |
| Edit | Post #286793 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Op Amp Hartley oscillator You are asking how to analyze this circuit: Forget about what you think it should be called. Before attempting to model specific aspects, first try to understand the circuit. The opamp provides gain of -R2/R1. For an ideal opamp, the output of the opamp has zero impedance in this circuit.... (more) |
— | over 2 years ago |
| Comment | Post #286766 |
In Eagle you can make generic symbols that can be customized with "attributes", which are sortof like environment variables that are set in the device. The device is what binds a symbol to one or more packages, and is a container for higher level information above the packages and symbols. Maybe Al... (more) |
— | over 2 years ago |
| Comment | Post #286745 |
Still no schematic. (more) |
— | over 2 years ago |
| Comment | Post #286745 |
You were warned several times about posting sloppy writing that you clearly didn't bother to proofread. I lost track what that runon sentence is about before even getting to the end. No, I'm not going to read it five times to figure out what it's asking, and neither should the volunteers here eithe... (more) |
— | over 2 years ago |
| Edit | Post #286745 | Question closed | — | over 2 years ago |
| Edit | Post #286743 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Small signal analysis of BJT in saturation region A resistor is not a good model for a saturated BJT. According to your graphs it is, but those are simplified. There isn't really a single slope for all base currents as your graph shows. Even if you can approximate some region of interest with a fixed slope, that slope will vary quite a bit betwee... (more) |
— | over 2 years ago |
| Comment | Post #286730 |
Don't tell me here. Put that in the question so everyone can see what is really going on. (more) |
— | over 2 years ago |
| Comment | Post #286730 |
I'm not going to answer until you explain the larger problem this fits into. You have abused the volunteers here with very unusual requirements that you simply dreamed up, and that would not present themselves in a real world situation. Either explain the real-world problem you are facing, or menti... (more) |
— | over 2 years ago |
| Comment | Post #286721 |
You fixed the image, but you haven't fixed the other problems I mentioned above. And, you added new problems. You have various combinations of inductance and capacitance being equated to dimensionless quantities. It doesn't take special electronics knowledge to get units right. Sloppiness is not ... (more) |
— | over 2 years ago |
| Comment | Post #286721 |
I've told you before, the last time only three days ago, to post images that we can actually read. Not only did you not fix that one, but now you're here doing it again. This time I deleted it since there is no point in having unreadable images here. I also downvoted due to the gross sloppiness. ... (more) |
— | over 2 years ago |
| Edit | Post #286721 |
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— | over 2 years ago |
| Edit | Post #286723 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Band pass filter given cutoff frequency and bandwidth I have decided to try design a band-pass filter with a cut-off frequency of 10kHz and bandwidth of 2 Hz. It's "10 kHz", not "10kHz". There needs to be a space between the number and the unit. NIST has a good document about this. Proper use of units and their presentation matter. I've sai... (more) |
— | over 2 years ago |
| Comment | Post #286705 |
Your original diagrams were already too small to read easily. Your new diagrams are worse. You really should be able to see that for yourself. The problem seems to be that you are trying to cram too much stuff into pictures horizontally. Keep in mind that any picture you post will be resized to a... (more) |
— | over 2 years ago |
| Edit | Post #286707 |
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— | over 2 years ago |
| Edit | Post #286707 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Finding voltage gain of Hartley oscillator I'm not going to get into rigorous analysis. My perception is that you're getting hung up on details and forgetting to think what the overall circuit is doing and how it works. I'll therefore stick to providing some intuition. An oscillator is what an AC amplifier becomes whenever there is posit... (more) |
— | over 2 years ago |
| Edit | Post #286700 |
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— | over 2 years ago |
| Comment | Post #286700 |
@a concerned citizen: You should make this an answer. It shouldn't be buried down here in comments. When you do, I'll delete this comment chain. (more) |
— | over 2 years ago |
| Comment | Post #286700 |
OK, "any" was too broad. "Any real-world" function would be better, since those can be decomposed to a set of sines. Since the system is linear, each sine component of the input can be treated independently. (more) |
— | over 2 years ago |
| Edit | Post #286700 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Complex frequency of a pole Your question doesn't make a lot of sense. for a sinusoidal input signal s = jω the pole exists at the resonant frequency ωr. Actually the pole exists regardless of what the input signal is. The transfer function is a description of what happens with any input signal. However if... (more) |
— | over 2 years ago |
| Edit | Post #286689 |
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— | over 2 years ago |
| Edit | Post #286689 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Effect of adding stages to a filter There are a number of misconceptions here. bode plot db/Hz First, it's "dB", not "db". Second that's not a Bode plot. Those are dB/Log(Hz). In other words, a certain frequency ratio results in a fixed gain ratio as the slope approaches the asymptote. You were told in your previous questio... (more) |
— | over 2 years ago |
| Comment | Post #286681 |
But your question starts out with <i>"I have to design a low-pass filter"</i>. Don't lie to us and jerk around the volunteers here like that. Two people have now wasted time trying to help you with this filter, only to find out the very unusual and difficult requirements were totally arbitrary. (more) |
— | over 2 years ago |
| Edit | Post #286680 | Question reopened | — | over 2 years ago |
| Comment | Post #286681 |
Then explain how you ended up with these specific requirements and what overall problem you are trying to solve. The question currently reads like a contrived problem, just like homework. (more) |
— | over 2 years ago |
| Edit | Post #286680 | Question closed | — | over 2 years ago |
| Edit | Post #286681 | Initial revision | — | over 2 years ago |
| Answer | — |
A: How to design a low-pass filter when certain conditions must be met Simple filters don't cause a fixed ratio change in amplitude (dB) for a fixed change in linear frequency (Hz). Making the amplitude change by -0.1 dB/Hz would be very difficult. This could be done with a very carefully designed digital filter. However, there is a loophole. Since only the averag... (more) |
— | over 2 years ago |
| Edit | Post #286673 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Siglent1104 oscilloscope channels lagging If all four channels are really connected to the same signal in the pictures you show, then there is indeed some skew between pairs of channels. Try swapping probes to see if the lag goes with the probe or the channel. Also try on the 1x setting. That should have less parasitic low pass filter... (more) |
— | over 2 years ago |
| Edit | Post #286661 | Initial revision | — | over 2 years ago |
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A: Limiting current to DC brushed motor I don't think there is a simple way to inherently limit the current to 10 A. The best approach seems to me to add a low side current sensor between the bottom of the H bridge and ground. The main tradeoff is getting enough current resolution without excessive voltage drop or power dissipation. ... (more) |
— | over 2 years ago |
| Edit | Post #286657 |
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— | over 2 years ago |
| Edit | Post #286657 | Initial revision | — | over 2 years ago |
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A: H-Bridge components and calculations Firstly, is this calculation for power dissipation correct? P = (I2 R) + (I V (ton+toff)/2 f) = 0.517 W Not completely. There are two separate parts that need to be considered. I2RDSON is the power dissipated by the FET when on. However, you can't use the average current. You have to av... (more) |
— | over 2 years ago |
| Edit | Post #286614 |
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— | over 2 years ago |
| Edit | Post #286614 |
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— | over 2 years ago |
| Edit | Post #286614 |
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— | over 2 years ago |
| Edit | Post #286614 | Initial revision | — | over 2 years ago |
| Answer | — |
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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— | over 2 years ago |