Questions tagged [power-supply]

An electronic device which supplies electrical energy to a load. Can be AC or DC input. Typically DC output.

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272 views

Short circuit protection

I have built an AC/AC cuk converter for an assignment I am doing. It works as such, I provide 50V AC in and I get an adjustable voltage out from 0V to 50V AC, depending on the duty cycle of the PWM ...
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330 views

hijack project microtransformer doesn't work well

I am working on a project that need to get energy harvest from smartphone headset jack.I find hijack project has a solution.the energy harvest circuit of it is below: it use coilcraft transformer ...
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860 views

beaglebone black doesn't autoboot when powered over jack or vdd pins

I have a BBB and it works quite well however when I power it over the Barrel connector or over the vdd pins rather then use the usb connection it doesn't automatically boot. When I put the barrel ...
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117 views

Most efficient way to generate 5.0 and 13.25 volts out of 2xAA

Working on an instrumentation device for some friends' lab. The MCU and most of the electronics require 5V @ ~15 mA, and 13.25 volts need to be fed to one side of a differential unity-gain opamp. The ...
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92 views

Calculate number of LEDs, and resistor values, when some is turned on/off from time to time?

The LEDs that I have available is 3.2V ~ 3.4V and 20mA (exLED 5mm LED). (i'm planning to use the clear ones). The resistors is 1/4W metal film resistors (1/4W Resistance Metal Film Resistors). And ...
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633 views

Building a +/- 150V DC power supply

I'm trying to build a +/- 150V battery powered DC power supply variable power supply. I have two of these 150V nixie power supplies: http://desmith.net/NMdS/Electronics/NixiePSU.html And was ...
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597 views

Connect sensor to 1-wire dual counter - different power sources

I am much more comfortable in software than hardware, but I'm working on a home automation project to track water usage. I have a Dinel AFP-966-S fiber optic sensor positioned over the water meter - ...
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452 views

Fried Beaglebone Black - Possible Reasons?

I've fried my beaglebone while powering it from a switching regulator which gives around 4.95V , The output voltage of the regulator was pretty stable with low ripple voltage. What happened was it all ...
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301 views

Obtaining rated current from 5 volt rail of pc PSU

I need to supply a minimum of 0.5 amps to each port of a number of 10 port USB 2.0 hubs. I have succeeded using 8 amp wall warts so I'm reasonable sure the hubs are capable. I'm powering 8 hubs so ...
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374 views

Maverick probe causes ardiuno to reset when touches grounded electrical item

I have a Maverick 732 probe connected to an Arduino for measuring temperature. The outer shield of the probe is connected to the ground pin on the Arduino, and the other wire is connected to an analog ...
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278 views

power supply frequency response

I have a question regarding the frequency response of a boost converter. I am curious to know what causes the "blip" at around 8kHz that causes the response to go up and then back down. At first, I ...
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1answer
90 views

Portable LED Power Supply & Driver

I have a question about power a portable LED light source. I understand the various ways to power an LED array but my question is more about the best practical approach. I have created a portable “...
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1answer
402 views

Does Armature current decrease as the load decreases?

I am being asked to find the speed of a 16.5kW shunt DC motor that is being supplied with terminal DC voltage of 300V when operating at 50% rated load with an armature current of 30A. I need to use ...
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1answer
549 views

Can I use a 150w 12v 775 DC motor with an old 800w PC PSU?

Is it possible to use a 150W 12V motor with a PC PSU? I know that it means that motor will draw a current of 12.5A from the PSU. The PSU can supply 20Amps in total on the +12V rail. As soon as ...
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1answer
33 views

Compromising on placement or routing of decoupling cap with BGA package

As far I know there are two important points related to power-supply decoupling capacitors. First the placement be less than 3 cm from the digital IC. Second the power tracks route pass through this ...
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1answer
46 views

noisy power supply for electric guitar pedal

I'm building a pedals board for an electric guitar. In order to have better integration, I replaced the wall wart power supply that was doing the job by this (BTW, the wall wart power supply is also a ...
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21 views

Simplified wiring diagram

G'day, I need a simplified wiring diagram to wire a 240V aquarium water pump using a float switch trigger powered by 12V transformer. I have LY2NJ HH 62P relay. Thanks for your time. Dirk
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21 views

Strange behaviour observed while SMPS testing:

I was doing load regulation test for the converter NB679GD. The converter supports input voltage from 5.5 V to 28V and produces a regulated output of 5V. Load is varied from 0.01A to 8A. The test was ...
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39 views

How does a traditional CC/CV circuit work?

I went through an application note from Texas Instruments referenced as snva829 ( the link http://www.ti.com/lit/an/snva829/snva829.pdf page 2 and 3) where they have discussed superficially the ...
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1answer
68 views

12v 25A power distribution PCB design

The goal is to control 18 devices by using rocker switches with LED. The total ampere can be up to 25A. The PCB size is 150mm x 250mm. The configuration is FR-4 with 2 oz/ft^2 copper. The bottom ...
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1answer
92 views

IC not getting the same power input

I have two different PCB boards. One is a sensor board and the other is a power board. I connect a 9V battery to the power board, to a 7805 5V regulator, and through a filtering process of some ...
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36 views

Energy Meter power supply advice/help

I've been assigned to start working on a smart energy meter project, it's been like 10 years since I put any work in AC. I would be sincerely grateful for any constructive advice. Now the 3-phase ...
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62 views

I need some opinions on my power supply design

I designed this power supply to function as an Arduino PS shield. I used four LT3080, one for each of four outputs and the basic cascade design was recommended by the manufacturer. There are four ...
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34 views

Sine wave clipping before rectifier when wire resistance is added at secondary of transformer in LTSpice

I'm simulating 4 different circuits, they are all power supplies, with loads, filter capacitors, rectifiers made by four 1N4007s, and transformers fed from 120VAC: They all have the same problem, ...
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15 views

half bridge secondary temp

I used this schematic for making a power supply. Output is single instead of double and is 36 V, 20 A. Core is ETD44. Freq is 50 kHz. Primary is 30 turn Litz wire (6 × 0.55). - - - Secondary ...
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34 views

LED Power supply for salvaged TV; what do I need?

I took apart a broken flat screen TV, and I'm turning it into an artificial light source. (https://www.youtube.com/watch?v=8JrqH2oOTK4&t=139s) I don't know how to tell what voltage/amperage power ...
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40 views

Using +/- 12v from a PC power supply to extend voltage range

I am trying to take a salvaged power supply as a back-end power block for this power supply https://m.aliexpress.com/item/4000390331993.html (powering a power supply with a power supply :) ) Anyway ...
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2answers
81 views

Why does this current inrush circuit not work well?

I've done some research and tried to implement a resistor and relay combination to limit current inrush for my power supply. How can this be improved as I am still seeing a peak of 85A at the ...
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49 views

Ground Loops in Power Circuit

I have a circuit with both logic-level control ICs (5v) and power electronics (FETs, relays etc @ 60v). I am powering the logic level supply from a USB power bank and the power side from my lab bench ...
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38 views

Smoothing SMPS ripple

I am designing a Raspberry Pi shield and it needs to have two separate supplies: one for the RPi itself, and one for the rest of the circuitry (consisting of energy metering ADE7758 chip). I plan on ...
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1answer
68 views

How to choose AC/DC adapter - high voltage low current vs low voltage high current

I got an LED light kit, 2 lights, each takes 60W, at 12-30V. I'm planning to use these lights separately, and need to choose between: 12V, 5A adapter 24V, 2.5A adapter Both will give me 60W, but ...
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22 views

How to get max V output from XBox360 power supply

I have a few Xbox 360 power supplys laying around and want to repurpose for led light project I am working on. The rated output is 12V 16.5A and thats perfect for my needs Problem is how do I get ...
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1answer
66 views

Drifting output

I have an old power supply that still works, got it from tandy when they were closing down it use to power the display unit of car head units, anyways the output voltage has drifted up from 12 to 22 ...
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40 views

Dual rail power supply

I'm currently working on a robotics project and I need to convert a 12V DC input to +3V, -3V and 12V outputs. The +/-3V is used to power motors in two directions. The 12V is used to power relays that ...
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1answer
34 views

Power Supply Lightning Protection

I am trying to design an AC/DC power supply for an LED aquarium light. My plan is to create a switching power supply which will first rectify the AC to a DC voltage before using switching to step the ...
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55 views

Issue with high induced circulating current in 115kv underground line

We are facing a problem with high induced sheath current during line testing with cross bonding. Initially, we got 27 amperes in link boxes when we injected 70 amperes in the line. Later with a few ...
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57 views

Can this burnt spot be fixed?

I cannot tell if the chip is fried, but it seems something bridged the solder point to the chip to cause the burn, this in a ps4 slim btw that does not power on and only giving blue light for a sec ...
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41 views

RF output power too high because of PSU cable

We have a situation where an integrated 868-920MHz RF chip is programmed to output the chip maximum of 14 dBm power. From professional chamber/measurement equipment 16 dBm is measured in the carrier ...
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44 views

Is it safe to make common ground between multiple voltage planes

I have a system where I have two power inputs and a single power output. One input from a battery(13v, 10A max) and one from solar cells(19v, 10A max). Then there is an 12v output which I connect to a ...
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2answers
45 views

Problem with transient on power rails

I have an AC to DC converter that outputs 5V. I then run this into 2 regulators on my board. The 4.2V regulator goes into a cellular module, and the 3.3V regulator goes into a microcontroller. I ...
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27 views

I need constant power to battery operated Christmas lights

I have 24v AC power to my landscape lights. I want to use this power to constantly light up some solar/battery powered Christmas lights. I believe the Christmas light strand is 1.5volts. How do I ...
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1answer
46 views

Wiring 220 to AC/DC transformer help?

On this AC/DC power module the terminals are labeled N and L, can I wire 220 line to line both to N and L? See link to part https://www.mouser.com/datasheet/2/468/RAC10-K_277-1661832.pdf
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1answer
32 views

Is there a way to periodically change the circuit a power supply is connected to?

I am attempting to build a device that contains an Arduino, a motor driver, and some motors. I'm using an AC to DC converter to power the device with 5v. What I'm trying to do is I want the power ...
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1answer
38 views

Need help designing power distribution system

I need help designing the power distribution system for a rocket test stand. I am new to power electronics so I am confused about how to go about it. I have to supply power to 8 solenoid valves that ...
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31 views

UPS For Mac Mini-based laptop - Sanity Check

My project is home-brewing a laptop that uses a Mac Mini and a small ~7" LCD display. To make it truly portable, I'd like the power system to work like a commercial laptop - ie, powers and charges off ...
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68 views

BJT Transistor (NPN and PNP ) Power Supply Monitoring Circuit

I am Understanding the Behavior of the following circuit with the help of simulation. Following Circuit Gives High signal at the opto coupler output when the supply voltage goes (V3) below 13.68 V. ...
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25 views

Why the Photovoltaic(PV) variations may cause shutdown in the main grid

If we assumed that PV generator is connected to the main grid, as the PV depends on solar irradiance it is considered to be a variable source. If the PV source can cause variations that could be ...
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27 views

Voltage variation and electrical fields Maxwell Equations

I actually know without knowing the reason or the mathematical expression of the physical phenomenon, that if we apply accross a capacitor a voltage which varies in function of the time, it produces ...
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41 views

Decoupling Capacitor between Vcc and Vio

The image below has used a 100nF capacitor between the Vcc and Vio pins. It says that doing this provides high-frequent short of the supplies. HOW?
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40 views

Are external components required for HLK-PM01?

Apologies in advanced as this is kind of a vague question and due to my lack knowledge in this specific sector. I'm designing a circuit using a HLK-PM01 as the power supply which is a 3W AC-DC ...