Activity for Pete W
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #291080 |
👍 just checking (more) |
— | about 2 months ago |
| Comment | Post #291080 |
re: the resonance- IIUC, it would overshoot at most 100% for a step input that's relatively fast vs the resonant freq. (more) |
— | about 2 months ago |
| Comment | Post #291080 |
Does the bus or device power get hot-plugged in the failure situations? Would there ever be a power-up or power-down situation that would move the circuit GND far from the chassis GND? (more) |
— | about 2 months ago |
| Comment | Post #291027 |
In saying "robust", is this in some way a field-wired system hooked up by potentially careless people (including oneself on a friday afternoon =P)? That would bring in scenarios of reverse power, and absence of ground connection, both of which are quite annoying.
Is ESD a consideration? (more) |
— | about 2 months ago |
| Comment | Post #291003 |
Great. Not trying to sell you on the BC's in particular. FWIW, the max mismatch in V_be would interest me more than the current-gain matching, usually. Other differences: compared to the 3904/3906, the BC847B/BC857B's have more LF gain and lower F_T. (more) |
— | about 2 months ago |
| Comment | Post #291003 |
If you're looking at smth like BC857, you can use the matched pair version BCM847/857 and their immediate relatives. So cheap there's little reason not to use the matched-pair version as a common building block whenever you need a bipolar transistor anyway. (more) |
— | about 2 months ago |
| Comment | Post #290874 |
re: corrosion
If there is a path for current to another wetted metal also in contact with seawater, there could be galvanic corrosion. Since gold is at the top of the galvanic series, the other metal would be the one dissolving, if that does happen. The gold would perhaps become coated with a very... (more) |
— | 2 months ago |
| Comment | Post #285392 |
Happy new year to you too! (more) |
— | over 2 years ago |
| Comment | Post #285392 |
Getting closer!! (more) |
— | over 2 years ago |
| Comment | Post #285242 |
anyway, an analog BW of 2kHz would be totally inadequate for actual bit rates you are likely to find. At least in "typical" serial port uses. Analog BW would typicall mean frequency beyond which the amplitude of a sine sweep test signal comes out attenuated to below -3dB. In frequency units, it needs... (more) |
— | over 2 years ago |
| Comment | Post #285242 |
what's the bit rate? (more) |
— | over 2 years ago |
| Comment | Post #285082 |
Makes sense, but it'll be a thing that needs explaining, again and again... (more) |
— | over 2 years ago |
| Comment | Post #284400 |
pros:
- many replacement power supplies;
- makes ground connection first
cons:
- doesn't stop other voltages with the same plug;
- doesn't stop confusingly similar plugs, namely the almost indistinguishable 2.5x5.5mm plug. Will feel about the same going in for the user, but unreliable ... (more) |
— | over 2 years ago |
| Comment | Post #281249 |
Thanks! // Yes the surface under the PCB (parallel to it) is functioning as the heat sink. (with clearance hole in pcb for screw) (more) |
— | about 3 years ago |
| Comment | Post #281144 |
My personal opinion, which I admit is not the norm. I found 2.4mm tip effective down to 1.27mm pitch with just the flux already in the solder wire (with the occasional solder bridge that's easily fixed with wick). With gel flux, 2.4mm tip does 0.65mm pitch, and with some care the 0.50mm. Technique re... (more) |
— | about 3 years ago |
| Comment | Post #280900 |
@2kind -- My thought process was to pick the outer Vbr to be greater than the max continuous voltage that could be present, which I interpreted from your description to be +32V. I.e. it would not conduct at +32V, nor would the series diode. The outer TVS is meant to do most of the work in any higher ... (more) |
— | about 3 years ago |
| Comment | Post #280822 |
did you look at the linked video? It looked pretty wild, moving down the line! (more) |
— | about 3 years ago |
| Comment | Post #280672 |
Could it be a damping resistor, to reduce ringing on the output of the driver? (more) |
— | about 3 years ago |
| Comment | Post #280614 |
Thanks. Spent a couple hours playing with it, hard to tell the difference between 2- and 3-transistor circuits, with the parts and equipment here. On solder-proto-board with 2n3904's, a tightly packed 3-transistor setup switched on in <25ns and switched off in <20ns, which was better than I expected.... (more) |
— | about 3 years ago |
| Comment | Post #280600 |
@Andy aka -- yes, you are right. It's something I have been avoiding. Thanks for the push to get me there. (more) |
— | over 3 years ago |
| Comment | Post #280600 |
@Olin, sorry for not being more clear. Edited to hopefully clarify what I'm asking. I didn't mean that it is an intentionally controlled ramp, rather that the output (i.e. collector current sunk from the node at the top of the cap) takes measurable time to go from 0 to the value that it will have. I ... (more) |
— | over 3 years ago |
| Comment | Post #280586 |
@Kranulis - now that you mention it... girlfriend's fine brand microwave just made a viciously loud "snap" noise over the weekend, which I figure is the magnetron. wanted to do a dissection for the turntable // UPDATE - supposedly working again. oh well (more) |
— | over 3 years ago |
| Comment | Post #280525 |
LTI works so well, it eventually takes almost no time to use. One can solve the "inside case" of many, many design problems using locally-linearized approximations, do this in like 20 minutes, and then spend days on analysis of obscure "edge cases". So it seems like all the time spent on more advance... (more) |
— | over 3 years ago |
| Comment | Post #280454 |
@Lundin , there's a lot of truth to that. At this scale, a streamlined programmer is a "nice-to-have". I'm trying to think ahead, get the technique down, etc. Having the ability to flash it in-house (even if pre-programmed) is valuable no matter what. We do lots of product variations and connecting t... (more) |
— | over 3 years ago |
| Comment | Post #280458 |
Very cool! Thanks so much. I will take a look at the details in the link you provided. PS- I would have to characterize this as "pretty fancy" : ) I like the safety switch on the hold-down latch, and the chamfered guides in the second-to-last picture. (more) |
— | over 3 years ago |
| Comment | Post #280393 |
Not sure if this way of faster turn-off would be important for a relay, maybe better achieved with a SSR? I found it useful for a solenoid that produces some mechanical action. The advantage of a TVS (avalanche diode) vs a zener, I'm not sure. In principle it is an opportunity to reuse a part that is... (more) |
— | over 3 years ago |
| Comment | Post #280393 |
I have used the TVS and schottky in series (pointing opposite way), for higher turn-off voltage in the coil. No obvious problems after it was appropriately sized. The catch is that the power dissipation in the TVS is higher in proportion to its voltage drop. With rapid cycling, the package size that ... (more) |
— | over 3 years ago |
| Comment | Post #280327 |
I always wondered too... [article](https://www.ecmag.com/section/systems/look-fiber-optics-above-you) ... apparently, the extra length of line is so that fiber splicing can be done on the ground ??? (more) |
— | over 3 years ago |
| Comment | Post #280152 |
Thanks! That makes it look a lot better. (more) |
— | over 3 years ago |
| Comment | Post #280152 |
No problem! Added the green clock waveforms to show this visually. It can also be done with an AND gate, which is more intuitive, but the XOR gate produces a 0-100% PWM, while the AND gate only 0-50%. Regarding the LaTex -- that would be great! (if it isn't much trouble.) I never learned how to do ... (more) |
— | over 3 years ago |
| Comment | Post #280139 |
Ok, will try to do that! (more) |
— | over 3 years ago |
| Comment | Post #279580 |
thanks. PS I think I misspoke, the '431 regulator works in some ways like an NPN. (the LM4041 works like a PNP) (more) |
— | over 3 years ago |
| Comment | Post #279580 |
Very nice. Minor note regarding specific TL431 part - 2.5V is a pretty big drop for the sense resistor. The TLV431 (and many other '431 types) have 1.25V. I think an NPN could also be used in the same position to reduce that further. (more) |
— | over 3 years ago |
| Comment | Post #279886 |
@leroy .. is a 0402 series element big enough to prevent arcing at 4kv? (more) |
— | over 3 years ago |
| Comment | Post #279962 |
Put the current limiting inside the loop, and the loop gain will lower output impedance seen from ADC. With caveat that for large/fast input swings, the OPA output might hit its limits sooner with more series resistance in the loop there (depending on the load of course). (more) |
— | over 3 years ago |