Activity for 2kind
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #290357 |
I need comparator output to be +-12V, not 0/5V. (more) |
— | 5 months ago |
| Edit | Post #290354 |
Post edited: |
— | 5 months ago |
| Edit | Post #290354 |
Post edited: |
— | 5 months ago |
| Edit | Post #290354 | Initial revision | — | 5 months ago |
| Question | — |
Converting 5V to ±12V I would like to convert 5V rail I have on PCB to ±12V. Existing solution is using boost converter 5V to 12V, and a buck for 5V to -12V. This feels bulky for what it's needed - here are the requirements: - +12V and -12V rail shall serve for powering opamp only - Ripple of the ±12V rails is not of ... (more) |
— | 5 months ago |
| Edit | Post #287480 |
Post edited: reply to questions |
— | over 1 year ago |
| Edit | Post #287480 | Initial revision | — | over 1 year ago |
| Question | — |
Minimizing Common Mode Radiation - Separating Grounds There are various different methods to keep common mode currents off the cables, one of them being discussed on the site here and with Olin's decoupling caps post on StackExchange. Slight digression - this is for some reason, extremely hard to comprehend to 9/10 engineers. One of the approaches He... (more) |
— | over 1 year ago |
| Comment | Post #286179 |
Erm I missed your comment. I understand what you are trying to say, but in this particular application it won’t be an issue. Implementing “IIR alike” filter in the ISR won’t take more than 3-5 cycles. Interrupting main thread every couple of hundreds of cycles for 3-5 is not critical.
In other us... (more) |
— | about 2 years ago |
| Comment | Post #286211 |
Can you give a bit of background for x64 and x32 oversampling logic? (more) |
— | about 2 years ago |
| Edit | Post #286179 | Initial revision | — | about 2 years ago |
| Question | — |
When do I need to put anti-aliasing filter in front of SAR ADC? Signal characteristics are: - 0 to 3.3V span - 0 to 100Hz range( there will be noise superposed on top with unknown characteristics) - Output resistance Rout=4700 ohm I want to sample that with a SAR ADC built in the MCU. ADC has following characteristics: - internal sample and hold c... (more) |
— | about 2 years ago |
| Comment | Post #286030 |
Not giving -1, but can you please include pictures in your questions rather than links? (more) |
— | about 2 years ago |
| Comment | Post #286020 |
How do you decide upon meaningful value? (more) |
— | about 2 years ago |
| Edit | Post #286025 | Initial revision | — | about 2 years ago |
| Answer | — |
A: PCB ground planes with isolated voltage You have a 6 layer design for controlling 24V brushed DC motor, galvanically isolated voltage rails(24V and the rest) and your question is how to separate them properly. There is no further reasoning why 6 layer design, why did you choose to isolate the PSU, is there something extremely noise sen... (more) |
— | about 2 years ago |
| Comment | Post #286021 |
If the SMPS is being fed by an ideal constant voltage source, adding an inductor would not have any value? Meaning, I am protecting against HF feeding my SMPS.
Is there other EMI aspect regarding having bigger input voltage ripple? (more) |
— | about 2 years ago |
| Edit | Post #286020 |
Post edited: |
— | about 2 years ago |
| Edit | Post #286020 |
Post edited: |
— | about 2 years ago |
| Edit | Post #286020 | Initial revision | — | about 2 years ago |
| Question | — |
How to choose the right value for input voltage ripple of an SMPS? Which important system design parameters need to be locked in order to estimate the maximum allowable level of the input voltage ripple of an SMPS? I have encountered ballpark figures of <1%, <1V throughout the various different designs and I wasn’t usually too worried about defining it - didn’t e... (more) |
— | about 2 years ago |
| Edit | Post #286012 | Initial revision | — | about 2 years ago |
| Answer | — |
A: Why are some PCB design software programs considered to be 'hobbyist' programs? I will try to cover additional aspects. Not eager on making changes - Big organizations are usually non very prone on changing their horse for the battle - sticking to their EDA choice from 20+ years ago. Doesn’t mean they would repeat it today. Pricing - I am yet to find the company which ... (more) |
— | about 2 years ago |
| Comment | Post #286007 |
What is the continuous current for 24V brushed motor you designed against? (more) |
— | about 2 years ago |
| Edit | Post #285849 | Initial revision | — | about 2 years ago |
| Question | — |
Flyback transformer for Vout > Vin This question is asked in an addition to https://electrical.codidact.com/posts/276436 Here is a Flyback converter mentioned there: Flyback Design parameters are: - Input voltage `125 volts` - Output voltage `500 volts` - Load resistance is `10 kohm` - Transformer turns ratio `... (more) |
— | about 2 years ago |
| Comment | Post #285458 |
How could 500V/125V ratio be achieved using 1:1 transformer? (more) |
— | about 2 years ago |
| Comment | Post #285186 |
Having seen optocouplers with ATEX certification, not 100% sure you could use POE as an isolation. Is there a reliability calculation requirement? Likelihood of F1 not tripping when it should?
My other comment without reading the IS would be is there a req to solve the issue you described through ... (more) |
— | over 2 years ago |
| Comment | Post #284304 |
Thank you, Olin!
"This is often done with rotor position feedback, like with Hall sensors. However, it can be done by looking at the back EMF generated, finding its zero crossings, and thereby finding where you are within the rotor's cycle."
If Hall sensors give you information where you are in t... (more) |
— | over 2 years ago |
| Edit | Post #284282 |
Post edited: |
— | over 2 years ago |
| Edit | Post #284282 |
Post edited: added detailed explanation |
— | over 2 years ago |
| Edit | Post #284282 | Initial revision | — | over 2 years ago |
| Question | — |
Driving PMSM machine as an AC induction machine Is it possible to drive a PMSM motor - here I am referring to an AC motor with permanent magnets(stator wounded, rotor with PM) - in a way that there is no externally mounted rotor position sensor(no hall, encoder, or resolver) using the scalar VFD method(V/f (Volts per frequency)) as one would typic... (more) |
— | over 2 years ago |
| Comment | Post #283361 |
Whoever downvoted, I would like to know the reason. (more) |
— | over 2 years ago |
| Edit | Post #283361 | Initial revision | — | over 2 years ago |
| Question | — |
Motor Controller - What might be the purpose of these resistors? I was looking at the video of the Tesla Model 3 motor controller(400VDC, 500A) disassembly and noticed a resistor network as in the picture below. They are 2k resistors(SMD code 202). See the picture below: Model 3 Inverter I was wondering what might be the reason for putting these resistors... (more) |
— | over 2 years ago |
| Comment | Post #282151 |
Thanks Coquelicot. Yeah, I could utilize micro that I have onboard, but agree that your circuit could be utilized in a lot of applications. (more) |
— | almost 3 years ago |
| Comment | Post #282139 |
Thank you Olin, like always. First circuit makes sense for PCB mounted relay where I can keep high dv/dt nodes on PCB. (more) |
— | almost 3 years ago |
| Comment | Post #282139 |
Thanks, Olin. Makes sense, I could try flipping L1 and C1, adding a PCB inductor instead of L1(contactor coil), and connecting the contactor coil in parallel with C1. Then the contactor coil would be the "load" of the low-side switched buck converter. Hmm, don't know whether this is feasible. (more) |
— | almost 3 years ago |
| Comment | Post #282127 |
I have a voltage source(35-60V range) and want to control the 12V/1.5A coil of the contactor without designing the 12V/2A buck solely for the purpose of contactor control. Moreover, 1.5A is enough for activating the relay, but I assume the holding current to be in the 300-500mA range. (more) |
— | almost 3 years ago |
| Edit | Post #282127 |
Post edited: |
— | almost 3 years ago |
| Edit | Post #282127 | Initial revision | — | almost 3 years ago |
| Question | — |
Contactor control - Higher voltage PWM I have a battery pack that consists of 18650 battery cells(14 cells in series max.). Hence, the voltage of the battery pack will be between 35V and 60V(to be on the safe side) I am designing a BMS in order to control it with cell monitoring, analog measurements, contactor control, etc. features bu... (more) |
— | almost 3 years ago |
| Comment | Post #281634 |
Thank you, Andy! Why would I care about ESR(dielectric+true resistance) losses at all and ignore the ESL when looking at AC? Impedance is something I should be caring about. The heck with ESR if ESL will kick into play(and it will at frequencies that are below and higher than the resonance one - plus... (more) |
— | almost 3 years ago |
| Edit | Post #281628 |
Post edited: |
— | almost 3 years ago |
| Edit | Post #281628 | Initial revision | — | almost 3 years ago |
| Question | — |
Capacitor ESR vs. Impedance One of the ceramic capacitors that I've found(link to the capacitor) specifies the following characteristics at 10 kHz: Impedance and ESR graph The difference in value is quite significant, almost 100 fold. Which graph on the picture above better represents real-world use-case? What is the... (more) |
— | almost 3 years ago |
| Comment | Post #281492 |
What might be the reason behind people recommending low-ESR caps put every 1m at the DC link cables for most of the RC stuff? I assumed it was because of the parasitic inductance with the input cables. Your analysis assumed pure ohmic cable characteristics. (more) |
— | about 3 years ago |
| Edit | Post #281478 |
Post edited: Changed the title |
— | about 3 years ago |
| Comment | Post #281478 |
"BLDC inverter" or BLDC motor controller. The unit takes DC input and converts it to a 3 phase voltage/current signal to control the torque or rpm of a motor. How to size the input capacitance of a BLDC motor controller taking input power cable length into consideration - mine calculation above doesn... (more) |
— | about 3 years ago |