Activity for 2kind
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Question | — |
Power Line Filter - Loaction of Cy and CMC A circuit under question: cmc filter Why are CY capacitors on the source side, and not on the load side? Henry Ott describes this with: “Because filter attenuation is a function of impedance mismatch, the role of the power line filter is to maximize the mismatch between the source and the loa... (more) |
— | 3 days ago |
| Question | — |
Standardized way of measuring AC line frequency In a general sinewave as below, is there a "right" way/"standardized" way to measure line frequency - and how do energy meters calculate that? - measuring pulse width of half-period, ie. time elapsed and then doing f=2/T - measuring pulse width of full-period, then f=1/T Is there a need to ave... (more) |
— | 3 days 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| Question | — |
Estimating the input capacitance of an BLDC motor controller Problem Description I am trying to design a BLDC inverter and I am in doubt of what would be the right approach for estimating the input capacitor size/type. Doing it empirically or throwing everything in SPICE is one approach, but I would like to understand what is going under the hood and at lea... (more) |
— | about 3 years ago |
| Question | — |
Max V/Hz value for motor I want to run a specific motor in the open loop. How to calculate the maximum ratio of V/f to run it? Am I looking at Ld or Lq value for this? Let's say these are the characteristics - haven't chosen it yet, but this one should serve the purpose because all important parameters are specified. ... (more) |
— | about 3 years ago |
| Question | — |
Isolated Digital Input - Overvoltage protection I am trying to build an active-low digital isolated switch capable of withstanding 32VDC voltage without creating any damage to the system. This is the snapshot of the circuit not fulfilling the requirement: Circuit "ISOPINPROG1" will be connected to the switch which will tie to the ground and... (more) |
— | about 3 years ago |
| Question | — |
Why 3.3V instead of 3V? Usual values used in doing electronics/power supplies are almost always round numbers: - 5V - 12V - 28V - 48V - 60V I understand that in some cases ICs are built to accept the voltage directly coming from the lithium-ion cell in order to simplify the power stage, therefore, havin... (more) |
— | about 3 years ago |
| Question | — |
BLDC motor - initial rotor position Sensorless BLDC motor controller are becoming more and more popular, especially with rising of the drone industry. Being able to detect where the rotor is at 0rpm or no load seems intuitive if we have hall sensors or resolver. However, what I am having difficulties understanding is how do you... (more) |
— | over 3 years ago |
| Question | — |
CAN Bus - Internal Oscillator Every time I needed CAN, I had just put external crystal and didn't think about it after that. It worked fine. I am wondering however whether the precisions of MCU internal oscillator is sufficient for up to 1Mbit/s and could I perhaps prove that on paper. Internal Clock Specification Datash... (more) |
— | over 3 years ago |
| Question | — |
Transformer - Vsec or Current rating parameter I am looking at the datasheet of the 7508170315(link) transformer and something seems strange to me. Itable from datasheet If I connect this to a 12V supply and expose it to 10us pulse: 12V10us/475uH = 252mA which is apparently less than the 350mAAC - is it actually? What 350mAAC mean in this c... (more) |
— | over 3 years ago |
| Question | — |
Flyback Converter - Output Ripple I am eager to create a flyback converter for driving the high side MOSFET. Here is a snapshot of my work so far: Schematic snapshot of the Flyback Converter Circuit 555 timer starts with generating 100kHz 12V signal on Q1. Q2 is monitoring the voltage on C2 and when it reaches around 18.7V forwa... (more) |
— | over 3 years ago |
| Question | — |
High Power Switch - High Side vs. Low Side Switching Imagine a battery pack with <=60VDC of maximum voltage and a load of up to 10kW of power(the PMSM inverter with the input capacitance of up to 1mF). The load is not always known - could be 100uF-1000uF input capacitance while the currents usually range from 20A up until 150A. The load is switched on/... (more) |
— | over 3 years ago |
| Answer | — |
A: Using FET based followers and design rules In addition to Olin's answer: > and I'm particularly interested in jfets and mosfets. If you decide to go down the FET route the dilemma between J and MOS gets down to home much you are willing to pay in order to have less noise in the next stage. MOSFET's have the conducting channel un... (more) |
— | over 3 years ago |
| Question | — |
ESD Protection - Differential Amplifier Circuit under discussion More about the circuit The circuit is sensing (low side sensing for many reasons) current used to power up the lights with 28V(part of the schematics not shown here -> relay with LC filter on the output side to limit the inrush current). The nominal current flowing th... (more) |
— | over 3 years ago |
| Question | — |
High Speed Design - Which grounding strategy to choose? Although I have done multiple PCB designs which passed FCC and CE equivalents using the MCU's/Multiple MCU's, I have a doubt about how to approach the high speed design using FPGA SoC - main thing that bothers me is choosing the right grounding strategy. By the high-speed design I mean >2GHz memor... (more) |
— | over 3 years ago |