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Questions tagged [power]

Where power is a primary concern for the design under discussion. Use the "low-power" tag when that applies.

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1answer
50 views

Linear Regulation Concept Confusion

I was watching one of Jacob Baker's videos (http://cmosedu.com/videos/f10/ece5472/lec1_ece5472_video/lec1_ece5472_video.html) At minute 19:30, he explains the concept behind linear regulation: His ...
0
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0answers
11 views

How do you properly install backup power delivery? [migrated]

I have a backup power bank made of an inverter and car batteries. It charges when the grid power is on and turns on when the grid power turns off. However, my "electrician" repurposed the grounding ...
2
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4answers
74 views

Handling brownouts during external flash writes

What techniques should be applied for writing flash in systems that have inherently unreliable power? Is there any good reading material on the subject? If I have a microcontroller writing sensor ...
0
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1answer
56 views

how the battery behaves in this diagram

My question is this. I'm using this ic mppt SM72445 along with a 250 watt solar panel, mppt output configured to 50.4 or 51 volts, 12-cell lithium-ion battery pack and bms, if the load is less than ...
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2answers
64 views

how a battery behaves in parallel to the charger with a shared load but with a voltage difference

how the battery behaves in this diagram how a battery behaves in parallel to the charger with a shared load but with a voltage difference
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0answers
38 views

Splitting a power supply to two monitors

I'm working on a project that requires 2 (identical) LED monitors, each of which has a separate power supply that outputs 19V 1.3A. To save space, I would like to instead use a single power supply ...
0
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2answers
51 views

Motor performance

If I was to run an electric motor rated at 24V 20A at 15V 10A and at 10V 15A what would the difference in performance be? Assuming everything is rated to safely handle more than that power.
-1
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1answer
62 views

Alternator droop characteristics

Two synchronous generators operating in parallel supply a total load of 200 MW. The ratings of the machines 1 and 2 are 100 MW and 200 MW. Machines 1 and 2 have governor droop characteristic of 4% and ...
0
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2answers
59 views

Another Power Supply question [closed]

I am trying to troubleshoot a problem with a battery charger that accepts 11-18V DC input and can output up to 24V/8A/80W. The power supply I am using is rated for 12V10A, but if I select 10A 8.4V ...
2
votes
3answers
86 views

Large Power System - Separate Earth Grounds?

I'm a EE working on a scientific instrument that is large in scale, like a building. The structure is all metal and will have many server cabinets and electronics equipment, motors, sensors spread all ...
1
vote
4answers
69 views

P-Channel MOSFET Flipped on Schematic

I'm designing a circuit which has a bluefruit nrf52832 micro controller built into it. When referencing the schematic provided by Adafruit I noticed that they had +VBAT going to the drain of the p-...
1
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1answer
73 views

Combining non-isolated switch mode power supplies in parallel into a single supply

I'm trying to combine several SMPSs each having a ~350VDC output @100mA each. Background: Purchased an unused batch of small DC->DC SMPSs in good industrial quality. Unfortunately they're too weak ...
1
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2answers
91 views

Why can the energy of local computing be written as \$f^2\$,not \$v^2\$

I saw this formula in this book: Wireless Information and Power Transfer: Theory and Practice And in the formula 14.8, it said: \$f_{i,n}\$ is the CPU frequency for the nth CPU cycle required for ...
2
votes
1answer
71 views

Is Inductive Kickback Protection not necessary for AC?

For DC inductive loads, typically a flyback diode is placed over the motor so that when the current changes instantaneously it doesn't have a chance to build upon the switch contact and then create a ...
1
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0answers
70 views

Repurposing or obtaining a cheap audio signal amplifier for school physics lab

I teach highschool physics, and want to connect my smartphone (LG V20) to a Chladni plate (vibrating plate for studying interference patterns in sound in solids). I have successfully done this by ...
1
vote
1answer
86 views

What is the role of the rightmost transitor in this circuit?

I extracted the following circuit from an schematic. It is part of power section. The switch on the +2V line is actually a GPIO from a microcontroller which turns to +2V when powering on the device. ...
0
votes
2answers
75 views

Limit 540 mA CC driver to 300 mA?

I have five 10 W, 34 - 38 V, 300 mA LED COBs I'm wanting to run these in series but to reach the voltage and watt range in the driver, I can only find a 540 mA constant current dimmable driver. I want ...
0
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0answers
23 views

Project involving the Texas Instruments TAS5720 amplifier - Power Requirements

The Google Home Mini uses the TAS5720 amplifier with a power supply which delivers 5V DC, 1.8A. From the datasheet it looks like this amplifier can deliver 20 W at 0.15% THD Continuous into 19 V / 4 Ω....
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votes
1answer
45 views

battery fully discharging [duplicate]

My goal is to use my laptop, a pioneer dj controller and 2 krk rokit 5's (50W class-AB amplifier boxes) for a party all at the same time for about 6-8 hours in a place without access to grid power. ...
0
votes
3answers
127 views

Low temperature batteries for use in Arctic

I've been checking the forum and Google but still haven't got precise solution to my current question. In short, we are looking for rechargable batteries for Arduino that survive under -40 Celcius ...
1
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0answers
25 views

What is the best way to isolate power hold-up circuit?

I an currently designing a hold up circuit for a computer and I need to keep this load isolated from other circuits that don't need to worry about a brief loss of power. The research I've done has ...
0
votes
1answer
44 views

Maximum Average Power Transfer and Efficiency

I've got this simple exercise about maximum power transfer. simulate this circuit – Schematic created using CircuitLab Where \$E_{th}=100\angle 0º \$ [V] and \$Z_{th}=100\angle 20º \$. Then I ...
1
vote
2answers
86 views

High frequency reduces power on circuit

I am not expert in electronics so there must be many errors that I am not considering. I designed a simple half wave rectifier that gives signal to a LDO voltage regulator of 3V3. In the input I have ...
3
votes
2answers
112 views

Confusion between the necessity of maximum voltage and maximum power transfer

This is a conceptual question therefore I want to ask with an example. I'm wondering in which cases impedance matching is used. For example, if one has a sensor which can be modeled as voltage ...
0
votes
1answer
82 views

Is this an appropriate smps design? [closed]

I am an engineering fresh graduate with an interest in PCB design. I have been learning KiCAD which is really fun and I enjoy it alot. A friend came to me with the reference circuit attached here and ...
3
votes
2answers
90 views

Not enough current draw through MOSFET

I am trying to control the current to a Raspberry Pi using a MOSFET and an ATtiny10. I am using a logic level MOSFET and it seems that the Pi needs about 250mA to turn on but it is only able to pull ...
0
votes
1answer
29 views

Triac wiring section

When wiring the power cables in a house, normative says wires must be typically 2.5, 4 or 6 mm2 in section for 230 V and 10...40 A. However, legs of a triac (thyristor, see this one by example) are ...
0
votes
1answer
48 views

USB cable for power delivery max voltage

I have a USB cable with the following markings on it AWM 80°C 30V VW-1 28AWGX1P 24AWGX2C Inside the cable there are 4 wires. I would like to use the VCC and GND ...
1
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1answer
67 views

Is a higher capacitance rating ok for filtering?

I am newer to electronic design and bought the mpu6050 sensor chip, which the documentation can be found here: https://datasheet.lcsc.com/szlcsc/TDK-InvenSense-MPU-6050_C24112.pdf It says that pin 20 ...
0
votes
1answer
48 views

I2C master and slave use different power sources

I have two slaves on the I2C bus. Before, both master and slaves used the same power source (2.8V), and the I2C bus works fine. Today, I changed the master to another power source (3.3V), keep the ...
1
vote
1answer
104 views

Designing a PCB with multiple supply voltages

I'm in a process of designing a 2 layer PCB for my device. The device is a master control board, and there will be 10 daughter boards. Various peripherals and things will be connected there: I need ...
0
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0answers
25 views

STM6600 voltage divider on VCC for high voltage applications

I'm evaluating the STM6600 on/off controller. My application has a 2-series LiPo battery with a voltage range of 6 to 8.4V, so I need to put a voltage divider before VCC as described in AN3271 (...
0
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2answers
41 views

Active Discharge Options

More and more frequently I am faced with a specification that requires the ability to discharge an output capacitance to a safe level X, in time Y. The circuit I am currently working on is 2000uF @ ...
0
votes
1answer
41 views

Equivalent power BJT transistor 2sa758 and 2sc898 for Sansui au 6600 Amplifier

I am restoring my Sansui au6600, at the moment I am recapping it, however I will have to replace the two final power transistors for the left channel which I found out to be faulty. The parts listed ...
0
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1answer
92 views

Aluminum Electrolytic Capacitor - current, power, efficiency

How to find out the efficiency of an aluminum electrolytic capacitor like this one. How to find out resistance of such a cap in order to calculate the time it takes for it to charge up or discharge? ...
0
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0answers
66 views

Accumulation of batteries' energy to rise electrical power capability

I am looking for a method to drive/pulse (ocasionally) an inductive load from a battery. The problem is, that the battery does not deliver enough power the load needs. But, energy is not a problem. I ...
0
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3answers
70 views

Line to ground faults

I am having a trouble understanding the concept of line to ground faults,and ground in general. In this simple single phase circuit, does current reach the load and the circuit operates normally? ...
2
votes
4answers
125 views

Looking for feedback on my microcontroller-controlled boost converter

Title is pretty self-explanatory. Here's a boost converter I've layed out: Instead of being driven by a chip, to save cost, I'm driving it from a micro. This micro has nearly no other tasks (some ...
1
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0answers
47 views

Raspberry Pi wake-up and battery power circuit

I am working on a Raspberry Pi (3B plus) project that - at times -needs to operate on battery power, and on external power whenever available. The RPI needs to operate only when a dedicated sensor ...
0
votes
2answers
56 views

Mechanical pressure contact

What I'm looking for is to be able to solder a mechanical pressure plate/arm to a PCB, where a plastic tab can be inserted. This contact (when connected) will complete the 3.3V/5V supply and turn on ...
0
votes
2answers
159 views

Can VCC and ground be swapped on a microcontroller?

We have a Particle Electron microcontroller connected to an Adafruit RFID Shield(PN532). Somehow, the microcontroller's VUSB (+5V typical) ended up connected to the GND pin of the Shield and the ...
0
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0answers
30 views

What test points to do for a switching system measurements?

I am working on a high-performance switching system. I the old ones there was no big issue in just touching a gate with an oscilloscope probe, but this time I have high voltage and very short (5nsec) ...
0
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1answer
66 views

No Output Voltage On Power Mux

I am building a board based on a working reference design. I've obtained the assembled board based on my design but the '3V3_OUT' signal is failing to carry power anywhere on the board. The issue ...
0
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2answers
62 views

Quiescent current on OFF/ON controller ICs seems high

I want to improve an existing OFF/ON circuit in a project I have. Why do most off/on controller ICs have such a high quiescent current (approx 6 uA)? Their sole purpose is to manage an off/on battery ...
0
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1answer
93 views

What are the main characteristics of high reactive power RF capacitors?

This question is related to this one. I have to design a high quality factor RF parallel resonant circuit, to be placed in parallel to the output of a medium to high power RF generator. Precisely, ...
0
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3answers
58 views

Regulating VAC transformer voltage

Good day all, I was wondering if there are ways to stabalize the AC voltage between 220 - 230VAC (standard mains voltage in Europe) if the mains output voltage drops say for example 200VAC? I am ...
5
votes
4answers
644 views

Does the neutral wire have any voltage?

In this article, the author talks about 3 phase and the magic of a missing neutral wire. And there's the following paragraph: In a 3-phase system the voltage between any two phases is 3 times ...
0
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1answer
28 views

DC Voltage drop multiplier confusion

I have half a meter of 18 AWG (1.02mm diameter) stranded copper wire and I am planning to run 12 volts with a maximum 6 amp load. Determining the cross sectional ...
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2answers
63 views

Transistor functionality in a given schematic

Can anyone tell me what is the functionality of the transistor in this schematic ?
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0answers
22 views

How to calculate ripple voltage in power supply? [duplicate]

In my design, the input is 50Hz and 230V and output is 12.2V DC. I try to calculate ripple voltage with this formula [(1.01mA*10ms)/1000uF] but I can not be sure.How can I calculate ripple voltage for ...