Activity for Pete W
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #291477 |
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— | 7 months ago |
| Edit | Post #291477 |
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— | 7 months ago |
| Edit | Post #291477 | Initial revision | — | 7 months ago |
| Answer | — |
A: Standardized way of measuring AC line frequency The simplicity of zero-crossing measurements is attractive. Regarding "Full period" zero crossing (i.e. time between rising-zero-crossings, or between falling-zero-crossings), compared to "half period" zero crossing measurement: Full-period has the benefit of being less sensitive to DC offset.... (more) |
— | 7 months ago |
| Edit | Post #291110 |
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— | 9 months ago |
| Edit | Post #291110 | Initial revision | — | 9 months ago |
| Question | — |
Humidity specs - is there typical reasoning for lower limit greater than 0? Question about relative humidity specification for electronics. Industrial automation, indoors, cabinet or instrument enclosure. The failure mechanisms at the upper limit are fairly intuitive. I'm wondering about the lower limit. Some devices specify 5%-95% RH - eg. Siemens S7-1500 PLC, which I... (more) |
— | 9 months ago |
| Comment | Post #291080 |
👍 just checking (more) |
— | 9 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) |
— | 9 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) |
— | 9 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) |
— | 9 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) |
— | 9 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) |
— | 10 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) |
— | 10 months ago |
| Comment | Post #285392 |
Happy new year to you too! (more) |
— | almost 3 years ago |
| Comment | Post #285392 |
Getting closer!! (more) |
— | almost 3 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) |
— | about 3 years ago |
| Comment | Post #285242 |
what's the bit rate? (more) |
— | about 3 years ago |
| Comment | Post #285082 |
Makes sense, but it'll be a thing that needs explaining, again and again... (more) |
— | about 3 years ago |
| Edit | Post #284771 |
Post edited: |
— | about 3 years ago |
| Edit | Post #284771 | Initial revision | — | about 3 years ago |
| Question | — |
What is sacrificed when buying cheaper oscilloscope probes (of same BW/cap/R/gain) I'm wondering if there are particular aspects of an oscilloscope probe's performance that tend to suffer, or failure points to look out for, if/when buying lower-end makes of oscilloscope probes (looking at the typical 1x/10x in 200-300 MHz BW range). (more) |
— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 |
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— | about 3 years ago |
| Edit | Post #284717 | Initial revision | — | about 3 years ago |
| Answer | — |
A: Low-frequency PWM-controlled Mosfet heater circuit This answer is regarding the resonance issue that C2 is fixing, and how it could be done with a smaller cap. There are two aspects of it. To start, consider the 5.6uH vs the 10uF capacitors. It can be stopped from resonating with the addition of a series resistor. With the modest DC current (powe... (more) |
— | about 3 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) |
— | about 3 years ago |
| Edit | Post #283508 |
Post edited: |
— | over 3 years ago |
| Edit | Post #283508 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Motor Controller - What might be the purpose of these resistors? I'd guess surge resistance and redundancy, rather than power dissipation. Looks like 10 stages of 5x parallel 2k going left to right?? So that's 10x400 = 4k. Perhaps used for parallel damping the DC link???? (the 6 subcircuits below would be 3phase half bridges??). Presumably then the DC link wou... (more) |
— | over 3 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) |
— | over 3 years ago |
| Edit | Post #281249 | Initial revision | — | over 3 years ago |
| Question | — |
Is there a tool or trick for bending TO220 leads Small-shop question here. Is there a convenient tool for making the bend shown below, other than a pair of pliers that happens to be just the right size, and is it worth it for qty low 100's?  Not a huge deal, it i... (more) |
— | over 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) |
— | over 3 years ago |
| Edit | Post #281144 |
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— | over 3 years ago |
| Edit | Post #281144 |
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— | over 3 years ago |
| Edit | Post #281144 |
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— | over 3 years ago |
| Edit | Post #281144 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Is there a particular type of lead-free solder that does not degrade soldering tips? PCB's and components are expected to be used with the common SAC solder, there's little reason to use SnPb, IMO. I learned on SnPb. After a brief transition for RoHS to re-calibrate the "feel" of it, never went back. Once or twice an oddball situation needed low melting point, used SnBi (also toxic I... (more) |
— | over 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) |
— | almost 4 years ago |
| Edit | Post #280900 |
Post edited: |
— | almost 4 years ago |