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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.

1
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1answer
83 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
72 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 ...
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0answers
20 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....
-2
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1answer
36 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
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3answers
117 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 ...
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0answers
30 views

Ceramic antennas for power transfer [on hold]

I am working in a magnetic coupling for power transfer between two coils. The other day I come up with the idea of using a ceramic antenna that are pretty small and easy to plug and tune for my ...
1
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0answers
21 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
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1answer
40 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
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2answers
81 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
97 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
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1answer
76 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
86 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
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1answer
28 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
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1answer
40 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
vote
1answer
36 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
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1answer
95 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
24 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
36 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
votes
1answer
64 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? ...
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0answers
25 views

what changes should i made to the circuit to work with 50Hz line frequency and generate 10 V ramp [closed]

what changes should i made to the circuit to work with 50Hz line frequency and generate 10 V ramp.
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0answers
38 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
66 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
122 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
42 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
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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
153 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
votes
1answer
63 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
votes
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
votes
1answer
83 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, ...
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3answers
55 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
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4answers
609 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
27 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 ...
1
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2answers
61 views

Transistor functionality in a given schematic

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

Minimum current to charge a 5v device? [duplicate]

I'm trying to use a DC-DC converter to charge a mobile phone. This is the converter....TRACO 12v-5v converter The converter is relatively low power, (5w) and can supply a maximum of 1amp. Testing ...
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votes
2answers
66 views

Can I hook up drone battery directly to transmitter? [closed]

I have a hs150 drone that doesn't come with a camera. I am trying to make my DIY FPV camera. The specs for my drone battery are this: Capacity: 600 mAh Voltage: 3.7 V Battery Type: LiPo Energy 2.22 ...
0
votes
1answer
37 views

Regulating a negative output from a bridge rectifier

I've managed to get a regulated 5V output from my bridge rectifier using a linear regulator. I now need to use another linear regulator to regulate a -5V. I can't for the life of me find how I do this ...
0
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3answers
96 views

Can a Variable Frequency Drive convert standard wall outlet (120V/15A/single phase) to ~220V 3 phase?

In my workshop I have a device that requires 220V 3 phase power, with a requirement of up to 1.5kVA. In North America, my wall outlet provides ~120V/15A single phases. (EDIT - my device can take +/- ...
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0answers
58 views

Determine the Value of R for the following cases:

I am unsure how to find an exact value for R, even if it is in terms of the other two variables.
10
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2answers
2k views

Using a microphone from the 1930s

I have an old Braun Cosmophon BMF2020 microphone at home, which I have long been wanting to use for good ol' fun. I have virtually no technical knowledge, so I am completely uncertain how to power ...
1
vote
1answer
32 views

Open-circuit alternator

Is it dangerous to run a permanent magnet alternator open-circuited? No current can flow so is all the power dissipated as heat? Is there even power generated in the inductive coils?
0
votes
1answer
35 views

Designing QuickCharge device

I want to make an ultimate powerbank for my biking trips. This involves accepting a dynamo input and slow charging the battery pack with its ~3W and also cramming as much energy as possible as fast as ...
0
votes
1answer
73 views

120 Watts and 7.2 Volts, how many Amps?

For a project I need to switch on a simple handheld vacuum cleaner with an Arduino. I am thinking of using a relay or mosfet. I opened the case and a 7.4 V 2200 mAh Li-Ion battery powers the motor, ...
0
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0answers
46 views

Not understanding current direction for this specific circuit (very basic question)

For the following circuit, I am for some reason just having troubles with understanding why the current (circled blue) moves in the up direction across the capacitor. Or for example, this following ...
4
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3answers
828 views

Power factor and cos φ

I am confused about the difference between "power factor" and "cos φ". Some textbooks state that those two quantities are equal. Other textbooks state that those two quantities are not equal. And ...
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1answer
51 views

What usually happens in a simple blender motor(for making smoothies) [closed]

Our 120V blender was plugged in to 220V. Im trying to take look inside and see if I could give a fix. What is usually the part that gets damaged? Thanks in advance.
0
votes
1answer
101 views

IR transmission power controlling

Maybe this is a big topic, I will explain my problem. (Reworded) If you want to adjust the distance IR communication can reach, you will face this problem: transmission power adjustment. That means ...