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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2 votes
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What is an intuitive explanation of using a boost converter for power factor correction?

By theory, a bridge diode and a capacitor bank can convert an AC sine wave into a DC signal, but the source current would appear spikey, having a power factor much smaller than unity. In order to ...
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0 votes
2 answers
39 views

How do I power an STM32 dev board with 9 V properly?

Dev Board: Discovery board with STM32F411VET What is happening in the MCU? I saw the datasheet with the 100-pin chip and and saw it has a bunch of VDD pins and a VBat pin but I'm not sure how the 5 V ...
0 votes
1 answer
87 views

How safe would it be to build your own 15 kW, 3-phase generator?

I need to get a petrol/diesel generator for my house with a power rating above 15 kW. It should be a 3-phase generator. The prices of such generators are extremely high. I have a working 2000 CC car ...
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-1 votes
0 answers
37 views

Switch to battery when the power supply turns off, operate fan for 2 min and then all [closed]

How to switch to battery when the power supply turns off, operate fan for 2 minutes and then all turn off battery power supply?
1 vote
1 answer
50 views

8 LEDs in parallel each having a switch with a constant voltage supply of 12 V

simulate this circuit – Schematic created using CircuitLab I have a question regarding the schematic shown above where I have 8 LEDs connected in parallel, each having a switch. Since the supply ...
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0 votes
0 answers
43 views

How to run a 12V device with a 5V supply? [duplicate]

I have a fairly low-power 12 V device which I'd like to power from a 5 V Li-po power pack. Assuming my 5 V source has enough total power, is there a simple converter I can connect between the device ...
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1 vote
1 answer
86 views

Battery replacement for 16 VAC

I have a mains power adapter that powers a small model train set. I would like the option to power this off a rechargeable battery, although I'm not sure this is possible, as it uses AC. My current ...
7 votes
11 answers
3k views

Easy and cheap way to sink more than 5 A from a power supply

For an experiment I need to check a current sensor but I need to parallel too many resistors to achieve that without damaging the resistors. I don't want to do that. The PSU is 12 VDC, 10 A and I want ...
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0 votes
0 answers
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Calculating required capacitance for ESC?

I'm working on an ESC design, but I'm not sure what capacitance is needed on the output terminals to smoothen out the voltage sags. Any ideas on how to calculate this?
5 votes
2 answers
666 views

How do modern CPU manufacturers determine the suitable base clock and the associated power?

Modern CPUs have very smart boosting strategies. When idle, they automatically underclock to conserve energy. When busy, they automatically boost or overclock. The adjustments are so dynamic today ...
1 vote
1 answer
37 views

Is it possible to get an estimate of the power consumption of a circuit by modeling it with controlled sources?

Let's say I have an op-amp. We can measure the power consumption of the circuit by multiplying the current supplied by the voltage supply with the voltage of the voltage supply. Now, suppose this op-...
1 vote
1 answer
35 views

How should I select a battery solution for my project? (24 V/150 mAh with recharging)

I'm designing my first ever electrical project and have questions about selecting an appropriate battery solution. I'll put the requirements up front. Max power draw - 24 V @ 150 mA Average power ...
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0 votes
0 answers
40 views

USB Charger (Samsung/Apple/Dedicated)

I have read a lot of lines about D+/D- Voltage when using different devices. Also the Article from maxim integrated. The conclusion is: I test it with iPhone X(iOS 15.6.1) and i found something ...
0 votes
0 answers
39 views

Increase boost converter power

I am looking to build this DC-DC boost converter. I know what parts were used to build a 150 W version of this design. I would like to build a 500 W version which basically has the same input and ...
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-1 votes
0 answers
39 views

Wireless outlet for monitoring and control [closed]

My idea is to monitor power consumption and automatically turn off the outlet based on time and power consumption (e.g. at night, but only if nothing has been running for a while). Most important is ...
0 votes
0 answers
44 views

Converted PC power supply producing too much voltage

I have converted two ATX PC power supplies to 12V bench power. They have worked flawlessly for the past 5 years. Suddenly, both are providing 17V+. What could be causing this? I have a 10ohm ...
0 votes
1 answer
95 views

LED 12 V, 30 A power supply blinking and 0 V output

I bought a 12 V, 30 A LED power supply for a chemistry experiment (electrolysis). The power dropped to 0 and the onboard LED in the power supply started blinking when the anode and cathode were in ...
0 votes
0 answers
56 views

Will these 2 electromagnet produce a 40kg (400N) attractive force?

Dear all, theoretically according to the electromagnet datasheet, it can attract with 20kg force, does that mean if I have 2 of the same electromagnet and if I switch it to different polarity from ...
1 vote
3 answers
106 views

20 W 400 kHz -1 MHz power amplifier

I'm designing a power amplifier for a piezoceramic transducer with these specifications: 20 W and 400 kHz - 1 MHz bandwidth. I do not have much experience with power amplifiers, so my design must be ...
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2 votes
4 answers
142 views

Why can't current flow in a conductor with a potential/emf on one end and earth on the other? Is there a mathematical expression?

Let's say I have a wire with one end connected to earth and the other end floating. Now let's induce a voltage/EMF of X volts into the wire. Considering the ground to be zero potential, why doesn't ...
3 votes
2 answers
91 views

RLC resonator to produce beautiful sine wave

simulate this circuit – Schematic created using CircuitLab I have read about the RLC tank which can help to resonate a pulse wave of a certain frequency so that it will produce a beautiful sine ...
3 votes
1 answer
299 views

Diode datasheet: What is "AI PCB" in the image?

What does "mounted on AI PCB" mean? Please explain with some pictorial examples.
4 votes
2 answers
1k views

Why is load rated in kW? [closed]

Why is a load always rated in kW and not in kVA or kVAr? Isn't it better to know how much kVA or kVAr an appliance or device has? Isn't it more useful?
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0 votes
1 answer
48 views

Can you calculate equivalent capacitance across a MOSFET if you know the rise/fall-times and voltage across it? [closed]

In my high frequency supply my MOSFET VDS signals seem to be falling/rising at much slower rates than the data sheet would suggest for a Gallium Nitride switch: https://www.ti.com/lit/ds/symlink/...
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0 votes
0 answers
32 views

Rotary inverter to transmit stable and high-quality power for power system with high penetration of renewable energy [closed]

From your point of view, do you think the highlighted information above is true? I think it's true and would like to do a research where I will replace electronic inverters with a motor generator set ...
-1 votes
0 answers
27 views

why isn't \$P=P_c\$ where \$P\$ is the power that we want to supply and \$P_c\$ is the power lost during transmission

When deriving the power lost during transmission, we use the following two formulae \$P=VI\$ where \$P\$ is the power that needs to be supplied, \$V\$ is the potential difference, and I is the ...
0 votes
1 answer
40 views

Reset push switch for LDO regulator

I have a XC6220B331MR-G 3.3 V LDO voltage regulator that supplies power to the MCU along with some other components on my board. The regulator has an enable pin which I connected to VIN so that the ...
1 vote
0 answers
24 views

Low-frequency inverter power transformer selection

I'm currently designing a low-frequency inverter from 42 VDC to 220 VAC (effective) that goes up to 300 W. The block diagram looks something like this: This is the FFT before the filter: As you can ...
0 votes
0 answers
45 views

AC/AC power supply for PCB

I am trying to source the right setup for powering this PCB: I have found an 18 V AC/AC power supply but it has a barrel connector: I am struggling to work out how to connect the barrel connector to ...
0 votes
1 answer
20 views

LiPo battery choke and cutoff momentarily when connected to heavy load

I bought a couple of this lipo batteries it outputs a 4.2 V when fully charged nicely but trying to use it with coreless motors that draws about 3 A of current each, the battery just gives a surge of ...
2 votes
2 answers
885 views

Cascading resistors in series

Suppose, let's assume an IC pin requires a 10kohm 1% tolerant resistor connected to ground for its proper operation. In that case, can someone tell me whether I can split the required resistors into ...
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0 votes
2 answers
50 views

48 V phantom power backup: switch off the 9 V backup battery with FET

I found this device here on the site. I need something to switch to a 9 V backup battery when there is a 48 V phantom power outage. How can I change the FET to switch OFF the BAT1 (9 V) backup battery ...
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3 votes
1 answer
127 views

Awesome magnetic levitation using Arduino

I followed a Youtube video here and it has instructions at here. The concept is easy which is try to levitate a magnet and balance it using Hall-sensor by changing the PWM of the electromagnet to ...
0 votes
1 answer
33 views

Measuring the power output of an amplifier with floating outputs

I have a d-type amplifier board which has "floating" outputs, i.e. the -ve output terminals are not connected to ground. I want to measure the power output and clipping point of this board ...
-1 votes
1 answer
69 views

Powering MCU and LCD screen

I’m using a 7805CT to regulate power for an Atmega328p for a project with an LCD screen. At first I was planning on having the LCD screen connected to the output of the regulator as well until I ...
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1 vote
1 answer
57 views

How to set Vref on a variable power supply

I recently recycled a 070XF01 voltage regulator from an old PCB. I want to make a 5 V power supply for a small project to power an ESP32 dev board. I'm still new to reading datasheets and this has ...
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2 votes
1 answer
116 views

Drive a coil with an Arduino

I want to drive a coil with a PID controller on an Arduino. I already made it on my computer, so the PID itself is not a problem. The coil has a resistance of a little less than 1 Ω, an inductance of ...
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0 votes
1 answer
28 views

How much power design for pulsed-type VCSEL?

I am designing a VCSEL board. VCSEL is 100 W optical power, typical operating voltage is 20 V, and operating current is 25 A. I think that the power calculation is 20 * 25 = 500 W. But it is pulsed ...
  • 3
0 votes
1 answer
48 views

Impedance of transformer

The percent impedance of a power transformer (%Z*) is handy for fault analysis, but isn't sufficient information for nominal circuit analysis. Why don't power transformer nameplates/specs have a ...
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1 vote
1 answer
53 views

When calculating energy from a pulse measured with an oscilloscope, will the timestep always contribute a relative uncertainty of 1/2?

I am trying to calculate the energy delivered by a short electrical pulse. I am using an oscilloscope to capture the waveform and then exporting it to a CSV file. My scope took measurements at a rate ...
19 votes
4 answers
2k views

How do large electrical grids stay in phase?

I am a math student with some background in physics so apologies if the question is naive - but I'm trying to understand how large electrical grids like the Eastern Interconnection maintain locally a ...
1 vote
1 answer
60 views

Amplify tiny voltages accurately

Hi all, above is a Schering's Bridge as a capacitance meter. Following the equation below, Rx resistor is fixed, whereas for capacitor Cx can be placed with an unknown value capacitor. R1 will be ...
5 votes
2 answers
608 views

Is there a general rule to calculate heat dissipation of electronic equipment?

Is there a general rule for calculating heat dissipation in electronic equipment if it's not listed in the specs? I have a couple of projects coming I'm working on that require this. For one situation ...
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0 votes
1 answer
78 views

Build a inductance or capacitance meter

Hi all, I am trying to understand the working principle of a Inductor or Capacitance meter and these circuit are common. Looking at the diagrams, the quality factor (sensitivity to frequency change) ...
5 votes
4 answers
908 views

Decoupling capacitor selection criteria for this multi-IC system

How can I select the decoupling capacitor values? I know the rule of thumb is 0.1 μF per VDD pin, but how does this work with multiple types of ICs (or if it even matters)? I'm trying to make a macro ...
7 votes
4 answers
1k views

Why is there a transformer in a radio receiver?

This circuit is a radio receiver. The above picture is quoted from here and here. My question is in the diagram. It looks like a transformer symbol. Is it even essential? Can't we use a transformer ...
3 votes
2 answers
274 views

Demodulator circuit design

Below is Triangular Modulation Output of a Triangle input wave Below is weird Modulation Output of a Triangle input wave when it is connected to demodulator The modulator circuit is quoted from Andy ...
0 votes
1 answer
72 views

INA219 load voltage stuck at 1 V

I’m using an INA219 and I’m trying to take a reading of voltage and current. When I’m looking at the current reading, it looks perfectly fine, however, the load voltage remains the same and it is ...
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1 vote
2 answers
92 views

Why does the LED turn off when I touch the feedback pin with a random conducting wire?

Typical application of the AL1663R IC I use is below. My question is: when I was trying to touch the feedback resistors' (R5 - R6) output with a wire, I saw the LEDs at the output went off. The wire I ...
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0 votes
0 answers
22 views

LLC Half-Bridge: How do I determine Qe_max?

How do I figure out what the value for Qe_max (curve 2) should be? TI's application note describes Qe_max as Qe at maximum load, and Qe is a function of the load, Re. I am confused on how to figure ...

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