# Questions tagged [power-supply]

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

5,342 questions
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### How to get +6V and -6V out of 12V PSU [duplicate]

I am designing a guitar pedal using OpAmps, and i need to feed them with +6V and -6V (beucase the musical signal is senoidal centered in 0V). I need to use a 12V DC PSU for the pedal, and i need to ...
38 views

### Supply current for dual supply

I have a circuit with 3 op amps who require dual +- 5 volt supplies. The datasheets mention their supply currents at 19 mA ,19 mA and ~5 mA. I intend to provide the -5 volts from a charge pump IC . ...
23 views

### PSU Voltage combines with different amperage capacities

In a common atx PSU has several voltage outputs with different amperage capacities such as 3.3V 25A, 5V 28A, +12 15A, - 12 1A. My question is simply that, if I make a connection positive side from +...
31 views

### Pros and cons of centralised vs decentralised power deliver for small devices

How does compare using one power supply for multiple devices vs each device having its own - regarding efficiency eg. power consumption? Model situation: Home automation using low power devices such ...
47 views

### How do i find Current Consumed by Circuit designed on Surface mount PCB without damaging PCB? [closed]

I have a circuit designed on PCB, and components (resistors, capacitors, diodes, Microcontrollers etc.) are all surface mount. I want to find the total current consumed by this circuit. I have traced ...
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### Dual channel linear power supply

As a learning project, I'm trying to create a simple linear power supply using LM317. The basic circuit is well documented on internet, but I want to create a variant that allows me to have multiple ...
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### a weird phenomenon with a 12V black & decker cordless drill [closed]

The background: I have a 10 years old 12V black & decker cordless drill, the batteries died successively, and I connected a 2 pin male plug try to use a PC power supply [PCPS] to run it. What ...
2k views

### Using a 12 V 3 A bilge pump on a 12 V 8.5 A LED power supply

I recently bought the following for a grey water system project I'm working on: 3 x 12 V, 3 A bilge pumps 1 x 12 V 12.5 A power supply I'm not an electronics expert, so my assumption was that the ...
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### Piezoelectric Project

I am currently working on project involving piezoelectricity and I'm in need of some advice. I'm pretty much a beginner, but I've been doing lots of research. I just need input to help fill some gaps. ...
44 views

### Dual rail power supply for audio needs to drive LED too, unsure of design approach

I have a +17V, -17V power supply for a headphone amp I am building, I would like an LED to indicate when the amplifier is turned on, but don't want to negatively effect the audio output by drawing ...
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### Powering a Behringer MicroMIX MX400 - Car Audio Application [closed]

I am installing a car audio system that will have TWO aux inputs; one in the dash and one in the rear passanger seat are. I decided to purchase the Behringer MicroMIX MX400 mixer. The power spec for ...
42 views

### Use rotary switch potentiometer from amplifier as main power switch

I am working on a battery powered audio project that uses a cheap amplifier (PAM8403 5V Mini 2*3W D Class Digital Amplifier Board). The volume can be changed using a rotary switch potentiometer. ...
38 views

### Block bids and offers in electricity markets

Why are offer curves and willingness-to-pay (or bidding) curves represented as blocks in electricity markets? What does each block signify? I'm trying to simulate an electricity market using MATPOWER ...
33 views

### Using a Relay with SMPS as load leads to contact welding after keeping energized for sometime

I am using a relay SRD-5VDC-SL-C(generic module made for diy projects) to control AC current going to my SMPS(120-300v AC to 12V, 2A DC) driving my LED strip. The relay is controlled by a Lolin ...
42 views

### Power Management

I am supplying power to a Arduino Uno that draws 45mA of current and a sensor that draws 20mA with a 9 Volt battery(ampere for battery is 550 mAh. How much power is the whole system consuming? I am ...
63 views

### Dual power supply with BJT. How to do tracking without opamp?

I'm making a 0-±12V 20mA supply for breadboard. Circuit simulates fine with ltspice. How to implement tracking (or tracking ratio) WITHOUT opamp? I found a schematic here https://groenholdt.net/...
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### How does splitting power cables work in ATX PSU?

I came across this Gamdias 650G PSU. Its CPU EPS has 8 pins at the PSU end but it’s split as 2 x (4 + 4) at the motherboard end. There are certain boards that now come with 8 + 4 EPS power sockets ...
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### (inverter repairs) Does reverse polarity can kill power MOSFETs in UPS inverters? [closed]

I had an old computer UPS (almost 7 years) and I modified it to use external battery (a 12 Volt motorcycle battery) since the old 12 Volt battery is completely dead and no replacement is available for ...
31 views

### Power Supply Transient Filtering

I'm implementing a Bluetooth module in my design and the modules datasheet calls for a filtering circuit on the 3.3V rail to get rid of transients when the LDO powers up (using a Torex XC6210 LDO). ...
40 views

### Backup power supply boost converter TPS61030

I'm developing a backup power supply using a supercapacitor and a TPS61030 boost converter based on this Texas Instruments circuit design. This is the circuit shown in the reference guide: and it ...
35 views

### Network Analysis for finding power delivered

We need to find the power delivered by the 5V source in the above network. I usually apply superposition theorem when I need to find the power delivered by a source when there are many power sources ...
36 views

### Variable voltage 110-220v input AC to DC 12v 15a 180W output power adapter with cigarette light socket

Can someone educate me how a variable voltage 110-220v AC input can be converted to identical 12v 15a 180W output without having to flip a switch at the input end? Would the DC output be steady ...
41 views

### High current buffer battery power management

In my application I have a motor that may require high currents (~140A) for some seconds. But I need to power the system for many hours from a 48V 10A switched mode power supply. The motor is current ...
91 views

### AC (230V, 50Hz) line detection using H11aa1

I am new to Power Electronics, I am working on to AC line detection using H11AA1 IC. Schematic is as shown here. With the following calculation, I figured out the resistor value R1=8K ...
35 views

### Which replacement Zener Diode should I use?

I am repairing a television power supply and have found a couple Zener Diodes that are bad. The service manual gives only a part number of VZMTZJ30DT. I have searched online for hours and cannot find ...
49 views

### Regulating High Power Wet-Cell Battery (Accumulator)

I'm currently working on long-term remote-sensing & data-acquisition. Thus, I'm planning on using 12V 45Ah wet cell battery (accumulator) for the supply. The system consists of microcontroller ...
91 views

### PC power supply charge 12v battery

Two part question. If I take the 11v and 5v, with diode to prevent 11v to flow to the 5v, will I get 16 volts? And will it change a 12v battery? Last how can prevent overcharge? Also this is an ...
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### Safety Rule: Sum of wire lengths over two phases may not exceed X. What is this for?

Everybody knows various flavors of the rule "don't connect too long electrical lines to an outlet / generator / whatever". They sometimes come in the form of "don't chain your extension cords". As far ...
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### Can Op-Amp (LM358) works as an integrator without dual mode power supply?

I am a noob with analog electronics, so pardon me for any mistakes. I recently started with Op-Amp and currently working on a project whereI am using Op-Amp in integrator mode to convert square wave ...
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### How to provide power supply to PCB?

This PCB is supposed to have 12-15V and 0.5A of current. How I should provide power to it? As I understand +V(as +) and OUT(as -)...
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### How to enable battery management IC

The TI's battery management IC BQ2403x have the chip enable signal which needs to pull up when working. There are four potential power sources to enable this CE signal which are: AC, USB, BAT and ...
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### LM317HV power supply

I have a few questions regarding the following schematics: ![/imga] ![/imgb] Initially I was testing the first schematic to see if it works good. The result of the tests were good, the power supply ...
292 views

### How do you calculate RC snubber values for a discrete bridge rectifier

I'm working on a small linear power supply for an audio amplifier (home/hobby use) and I want to add an RC snubber on the rectifier diodes. I know this might be overkill, but I'm looking at it as an ...
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### Amplifying high frequency AC using op-amp or alternative methods

Right now, for my project, I am trying to design a circuit for generating 10 kHz to 1 MHz AC signal with ~80 Vpp to 100 Vpp. Currently, I chose to the AD9850 chip for generating AC with Vpp being ...
116 views

### How does a split rail supply work and how to design one?

I need a split supply for a project I am working on and there's no way around it, however this is very unknown to me. How does one even design one and how does it work? I find it confusing to do a ...
52 views

### What is the best starter adjustable power supply for pretty cheap (preferably ac/dc) [closed]

Please I am just a kid no \$8953739857239875 power supplies. Btw I am an inspiring electrical engineer and I'm 10 so I need a bit of help so I don't how do I put this nicely, ahem trip the breaker if ...
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### Is it safe to externally power a net normally powered by a SMPS (3.3v buck)?

I have a board which has a microcontroller powered by a 3.3V buck and I need to know if it will harm the buck to power the net that the buck usually powers with a bench-top power supply. A bit of ...
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### I need help to identify this old SMD device

I'm working on a circuit and I can't find information on this component (see picture). This hybrid circuit is part of an old industrial PSU. It is a PFC circuit based on UC3854 but I don't know if the ...
56 views

### Converting 5V to 3.3V with 100mV ripple max, preferably without board

I am working on a project in which there is an existing enclosure, an existing power supply board and a bought board that I need to interface with. The board I need to interface with needs to receive ...
64 views

### Does the switching frequency and ON/OFF time duration of LED affect the power consumption of LED?

I want to drive the electronics consisting a controller with different peripherals on its I/O pins, one of which is LED, with 3V coin cell battery supply. I want to determine if its switching ...
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### Most cost effective way to power a bunch op amps +/-12V supply rails from +5V

I'm searching for the most cost effective way to supply +/-12V for 12 TL084 op amps. Reading in the datasheet, it seems they have a typical current output (with load) of about 20mA. So, 12 * 20 = ...
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### Single battery for different voltage components

So I have a 12V DC motor and a 6V stepper motor. Ideally, I would like both of them to draw from the same 12V battery pack (due to build constraints). The DC motor will be fine but the extra 6V ...
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### Power NMOS used as voltage switch

I've designed a PCB schematic that uses a MOS device to switch one of the higher power rails. I've looked through the datasheets many times, and believe it should work, according to the Current-...
137 views

### DC-DC step down 12V to 5V source versus straight 5V source

Here is the scenario: I have a project needing 3 supply powers: 3.3V to run the microcontroller (max 100mA) 5V to run a bunch of adressable LEDs (max 8A, the most current intensive) 12V to supply op ...
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### Operating Voltage Range Question

Almost certainly a neophyte question. I'm trying to understand the difference between nominal voltage and operation voltage range. My intuition was that, for a given power supply, it would hold a ...
60 views

### Audio jack detection to turn on device without power loss

I'm trying to make simple headphones amp and I wonder - is there any way to use stereo jack connector with N-C switches like this: to turn on the amp so the battery is mechanically disconnected? I ...
28 views

### Searching for a transformer for the power board of an Equipe 2400 studio blitz Power/controller

This is for a photographer friend, feel it would just be too bad to let this beautiful equpiment stay in the closet because of, as far as I can tell, one blown transformer. The unit is made by Bowens ...
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### Integrated 5V uninterruptible power supply (UPS) with a lithium cell?

I'm trying to figure out the best way to implement a UPS for an embedded system that runs from a 5V supply. Essentially the system has a 48v to 5v, 1.2A output DCDC converter that powers my system. ...