Activity for Olin Lathropâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Answer | — |
A: Floating circuitry and diodes is the "X" point floating when there is no 12V applied ? Perhaps over a limited range, depending on whether the 12V line is left open or connected to something other than 12V. Case 1: The voltage on X is bounded by the Zener diode. X can't be more than one diode drop below ground, or th... (more) |
— | 10 months ago |
| Edit | Post #288853 | Initial revision | — | 10 months ago |
| Answer | — |
A: Choosing between common-drain JFET amplifier, and common-source The first circuit uses the FET in follower mode. That means it works as an impedance buffer with a gain a little below 1. Such configuration can be useful to turn a high impedance signal into a low impedance signal. The second circuit uses the FET as a common source amplifier. This inverts the ... (more) |
— | 10 months ago |
| Comment | Post #288844 |
Those opamp links don't go to datasheets. They go to some product page that asks me to accept cookies. No thanks. (more) |
— | 10 months ago |
| Edit | Post #288784 |
Post edited: |
— | 10 months ago |
| Edit | Post #288784 |
Post edited: |
— | 10 months ago |
| Comment | Post #288784 |
This is getting off the topic of this question, and is better addressed in a separate question. (more) |
— | 10 months ago |
| Edit | Post #288784 |
Post edited: |
— | 10 months ago |
| Edit | Post #288784 | Initial revision | — | 10 months ago |
| Answer | — |
A: Ground pour on outer layers on 4-layer PCB I would not do deliberate ground pours on a board like that. It's relatively small, and not exceptionally high frequency. I also wouldn't try to guess what effect or not it might have on the board fab process. I've put similar microcontrollers on larger boards many times and not had any issues l... (more) |
— | 10 months ago |
| Edit | Post #288757 | Initial revision | — | 10 months ago |
| Answer | — |
A: How to convert dv/dt of noise into frequency for filter capacitor selection? It looks like you've sort of re-discovered a motivation for Fourier analysis. The difference between looking at slope versus frequency content is exactly the difference between time domain and frequency domain analysis. Both are perfectly valid and provide the same ultimate answers. However, one o... (more) |
— | 10 months ago |
| Edit | Post #288740 |
Post edited: |
— | 10 months ago |
| Edit | Post #288740 |
Post edited: |
— | 10 months ago |
| Comment | Post #288641 |
I don't see anything wrong with a question that was prompted by current events, as long as it asks about real EE issues like design tradeoffs. In my opinion, this question meets those criteria. (more) |
— | 10 months ago |
| Edit | Post #288740 | Initial revision | — | 10 months ago |
| Answer | — |
A: Should posting on Meta affect reputation? Yes, votes on meta should not factor into rep. Meta downvotes indicate disagreement, not that you're a terrible person, have the IQ of a garden slug, and cast dispersions on your heritage like they do on the main site ;-) Users should be free to express their opinions, whether popular or not, as ... (more) |
— | 10 months ago |
| Comment | Post #288688 |
Tell us what you ultimately want to achieve, not how you imagined to go about it. All you've said is that you want to *"generate strong magnetic fields"*. Driving an electro-magnet does not necessarily require resonance. Maybe a class D amp? "Strong" is a useless spec, so we have no idea of what ... (more) |
— | 10 months ago |
| Comment | Post #288641 |
What's with the downvotes? This question is well written, to the point, uses pictures well to illustrate the point, and is a legitimate question prompted by current events. It's not asking a user-level question about a game controller, but design issues that make products suitable for different use... (more) |
— | 10 months ago |
| Edit | Post #288708 | Initial revision | — | 10 months ago |
| Answer | — |
A: High power LC circuit with programmable resonant frequency What you are asking for is totally unrealistic, and your numbers don't add up. With 10 mH and 80 µF, the resonant frequency is 178 Hz. Getting down to 1 Hz even with 10 mH would require over 2.5 F. Keep in mind that with the inductance fixed, the capacitance required for resonance is inver... (more) |
— | 10 months ago |
| Edit | Post #288652 | Initial revision | — | 11 months ago |
| Answer | — |
A: Titanic submarine control considerations I don't have any special knowledge about how submarines get controlled, so this is mostly speculation. I expect that the actual controls are fine. There seem to be the necessary degrees of freedom, and as you say, people are already familiar with the interface. In that sense I don't see anything... (more) |
— | 11 months ago |
| Comment | Post #288550 |
@Lundin So say that in an answer. It's OK to answer with speculative information as long as it's labeled as such. I don't want the information to get lost here in a comment chain. Comments are not for content. (more) |
— | 11 months ago |
| Comment | Post #288550 |
@Lundin You should make this an answer. This information doesn't belong in a comment. (more) |
— | 11 months ago |
| Edit | Post #288515 | Initial revision | — | 11 months ago |
| Answer | — |
A: Sensing 3 states in a single mcu pin using firmware Starting with your first circuit: It seems a little klunky, but should work. I don't like the D1 and D2 diodes. The reason I placed D1 is to avoid triggering the mosfet with very low voltage like 2V to 4V. Is D2 really necessary? The input voltage threshold for sensing high is the 8.2 V... (more) |
— | 11 months ago |
| Edit | Post #288474 | Initial revision | — | 11 months ago |
| Answer | — |
A: How to change the polarity of an input using a single switch? The difference between your two options is which polarity the input floats to when left open, and whether there is an overall inversion. Adding the inversion in the firmware would require one more pin from the chip. Not necessarily. I was envisioning inversion or not would be specified by conf... (more) |
— | 11 months ago |
| Comment | Post #288440 |
It seems you want to be able to invert the sense of an input into a microcontroller. Why not do the inversion in the firmware? There should be no need for hardware polarity flipping. (more) |
— | 11 months ago |
| Edit | Post #288415 | Initial revision | — | 11 months ago |
| Answer | — |
A: Variant of a Mosfet's Gate-Source protection If the TVS truly clamps the "+12V" line to 25 V, then the VGS of Q1 can't exceed 25 V. However, if you want to limit the gate voltage, limit the gate voltage. A Zener between gate and source guarantees that directly. You may still want the TVS to clamp the incoming power voltage for other reason... (more) |
— | 11 months ago |
| Edit | Post #288391 | Initial revision | — | 11 months ago |
| Answer | — |
A: Why do I need electrodes for ECG measurements? The electrodes electrically connect to the skin in order to pick up tiny signals produced by the heart muscles. Electrically you're a bag of saltwater. Your skin (the bag) has a relatively high resistance. The innards (the salt water) has relatively low resistivity. To get good signal to nois... (more) |
— | 11 months ago |
| Edit | Post #288390 | Initial revision | — | 11 months ago |
| Answer | — |
A: Synchronization of clock of satelite with devices here on the Earth First, the time dilation experienced by a satellite is tiny on a human scale. It takes sophisticated algorithms and lots of processing power to measure time differences between a spot on earth and various satellites. That's how GPS works. Early GPS receivers were rack-mounted boxes before integrat... (more) |
— | 11 months ago |
| Edit | Post #288233 |
Post edited: |
— | 11 months ago |
| Edit | Post #288233 |
Post edited: |
— | 11 months ago |
| Edit | Post #288233 | Initial revision | — | 11 months ago |
| Answer | — |
A: Oscillator with non-rechargable battery There actually seem to be two different questions here. Can a primary (non-rechargable) battery be damaged by forcing reverse current thru it? Yes. Primary batteries are only intended to source power, not sink it. Forcing reverse current thru them, especially for significant lengths of time, ... (more) |
— | 11 months ago |
| Edit | Post #288231 | Initial revision | — | 11 months ago |
| Answer | — |
A: Confusion in operation of analog computer The poteniometers (what you label as "variable resistors") are almost certainly just floating pots. If their ends were permanently connected to power and ground, then they'd be voltage sources, not pots. You might temporarily connect the top terminal to power, the bottom to ground, and measure the... (more) |
— | 11 months ago |
| Comment | Post #288222 |
I don't know what other form you've seen pots in, but a rotating shaft is very common. In any case, you need to fix the question. (more) |
— | 11 months ago |
| Comment | Post #288222 |
No, those are pots (potentiometers). You even label them yourself as <i>variable resistors</i>. Remember, this is an <i>analog</i> computer. Switches are digital. (more) |
— | 11 months ago |
| Comment | Post #288222 |
I looked at your full image carefully, and the only rotary switch selects one of three frequency ranges for the built-in square wave generator. The silver-colored 10-turn knob above the rotary switch provides the fine adjustment. I see no rotary switch where <i>"set the rotary switch to multiply th... (more) |
— | 11 months ago |
| Edit | Post #288192 | Initial revision | — | 11 months ago |
| Answer | — |
A: High Speed Digital Communication Bus Probing One of the first things you should do is provide a connection for the scope probe ground. If you think you'll be regularly looking at signals on this board, then one of those little loops or pins to clip a scope probe too would be useful. If it's a one-off problem, then just a thru-hole pad would b... (more) |
— | 11 months ago |
| Edit | Post #288165 | Initial revision | — | 11 months ago |
| Answer | — |
A: SDR SDRAM PCB Timing Budget It would help to provide links in your question to the datasheets. Without the datasheets I can only give general advice. Look a the memory datasheet and see what the setup and hold time requirements are. There is always a window of time around a clock edge where the data must be held steady on ... (more) |
— | 11 months ago |
| Comment | Post #288163 |
We need to see exactly what you connected to this chip. Show the schematic. It would also help to provide a link directly to the datasheet of the chip. (more) |
— | 11 months ago |