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

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1answer
29 views

Can I use a halogen transformer as a power supply?

I have an electronic transformer which is meant to be used to drive a 12v halogen light. The specification on the electronic transformer box says 220-240VAC input, 12VAC output 20-60W. When a 50W ...
-2
votes
0answers
47 views

circuit design for getting 10 A , 350 mA dc output [on hold]

I need to get a DC output of 10 Volts and 350 mA from AC input of 230 volts. What would be the best circuit for it. I tried using bridge rectifier but its current rating is low . I mean I am not ...
3
votes
2answers
343 views

Microcontroller soft off circuit not working - why?

I was making a board with an atmega328 mcu (to be used with Arduino libraries) to do some one wire communication stuff. Since I was etching the board anyway, I decided to try and implement a simple ...
1
vote
1answer
50 views

How do I get multiple voltage lines from a single PSU output?

Suppose I have a regulated power supply that has +20V and -20V outputs, and an amplifier circuit that uses them. I also have a push-button (not momentary) power switch with an integrated LED which ...
1
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0answers
33 views

DC-DC Converter 48VDC to 12VDC [on hold]

I Plan to make buck converter that converts 48VDC to 12VDC 25A. Is there any IC in the market that can make this happen? Thanks in advance!
1
vote
2answers
35 views

Confusion: Power Bank and Mobile Charging [on hold]

MI Power Bank 10400 mAh rated power bank. It has 93% conversion rate. It uses the USB standard to charge phones, so I am assuming a 5V output voltage. So the total energy 'content' = \$10.4A \times 5V ...
-1
votes
0answers
53 views

Adding more current to circuit [on hold]

I have a high voltage supply (aprox. 20kV) and I would need to increase the current while keeping the voltage. Is there any way you can think of or is it impossible? Thanks.
4
votes
3answers
691 views

What is the difference between different types of GND

I would like to know the difference between different types of Grounds like AGND, SGND, Battery Gnd, PGND. Are all the grounds not same? Cant we connect the device to any one of these grounds?
0
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1answer
31 views

Combining different power sources for hybrid power plants

How can we combine two different power sources? For eg:AC output from a windmill and DC from a panel situated near? Will the combined output be greater?
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3answers
109 views

What happens if I supply a higher voltage than the rated voltage of my jack?

I want to replace the original jack from my notebook with a new one since it is broken (and I would like to avoid to replace it with the same as the original). The original AC adapter supplies 19V and ...
2
votes
1answer
61 views

Determine the maximum load of a power supply

I am trying to upcycle an old bit of tech I had lying about. The main part I am looking to recycle is the power supply however I do not have specs of the power supply itself. I have measured an output ...
1
vote
2answers
249 views

How hard/possible it is for an engineer to make this happen?

I need to get one of these power supplies to use it in something I'm developing. The problem is that where I live there are no shops that sell this. What I need is this: If I'm not mistaken, this ...
1
vote
3answers
560 views

Very small 12V DC power supply

As a second part of my bad question about voltage converters . Well, I was asking about a regulator to get me from 220V AC/DC, into 12V DC . A regulator can't do that , but today I got the Apple ...
0
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0answers
25 views

Help with designing negative part of Dual-Sided SMPS

For a project of mine, I'm trying to make a dual-sided SMPS that has independently variable positive and negative supply rails, current limiting, short circuit protection, etc etc... My current plan ...
1
vote
2answers
153 views

Connecting LEDs to 220v without using a power supply

I'm designing a backlit custom picture frame, and I want to include the power supply (or the lack of one) inside the body of the frame. The problem is, since the frame design is more or less thin, I ...
1
vote
0answers
43 views

How to estimate max current draw from an unknown PSU? [on hold]

I have a couple of PSU boards from Sony PS2 consoles. They convert 230VAC to 12VDC and would be useful in a couple of my future projects. Unfortunately there's no information how much current they ...
0
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0answers
58 views

how to protect a 12 volt operating DC LED Bulb from 230 volts mains supply

I have made a DC Led BULB (7 watt) which is working on 12 volts input. By the way its input voltage range is 12-48 volts DC (using BP 1601 regulator ic) Now problem is that when i gave some bulbs to ...
0
votes
1answer
31 views

Connect / disconnect USB while external power source remains connected

I have some arduino mini pro collecting environment data, so they operate a long time collecting and I need to connect Gnd - Rx - Tx once in a while to transfer data to my PC, and then disconnect. I ...
2
votes
0answers
49 views

What is the lowest noise power source?

In particular two cases. 1) Unregulated: Supercap versus battery. 2) Regulated: Best regulation method to power precision low current analog circuits again with battery versus supercaps. I know ...
2
votes
1answer
57 views

How to use CR2032 in parallel with a power supply?

I have devices that is powered by a coin cell battery, but occasionally they fail and I would like to run them in debug mode to find the problem. Debug mode requires more power than the coin cell can ...
1
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0answers
52 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 ...
1
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0answers
49 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 ...
1
vote
0answers
33 views

Beaglebone black 3v3 rail

I am thinking about building an IO board which sends data to a Beaglebone black via SPI bus. In order to avoid the issue here, I want to just use the 3v3 pin supply to power the IO board so whenever ...
0
votes
0answers
50 views

Using a LM1875 instead of a LM675 for virtual ground

I've been gawking at the data sheets of these two, and I don't see any great disadvantage in substituting the TI recommended part (LM675) for the audio part LM1875 in this application (virtual ground, ...
2
votes
1answer
90 views

Power supply overshooting during power up and power down

My programmable power supply project in progressing slowly and now it's time to do something with overshooting of linear "postregulator" during power off and power on. Overshooting on step response is ...
1
vote
1answer
56 views

Dual Power Supply Switch?

So the question is short, how do i connect a single switch to a circuit that has a dual power supply (+/-) connected to it? Or do i have to use an special kind of switch?
0
votes
1answer
118 views

What kind of “locking” barrel connector is this?

I am looking for a replacement for a barrel connector; this is a locking connector (PN: PWRS-14000-260R for a Motorola FX9500 RFID Reader Country of origin: CHINA) however the locking 'fins' (for lack ...
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0answers
18 views

Rigol command to find if channel is enabled and max voltage/current can be applied

Hi I'm using RIGOL 832A in lab I just want to know if there's any command which returns answer 1. If channel is enabled? 2. Max voltage that can be applied to channel 3. Max current that can be ...
0
votes
1answer
85 views

What common factor could be causing wrong voltage on both rails of this PSU?

I'm trying to figure out why the 43/-43V rails in this PSU are actually reading 41/-41V. I'm presuming that it must be due to a single shared component that is out of spec, but I'm not sure what. I ...
0
votes
0answers
57 views

Which logic gate arrangement would be better?

I have converted an old ATX PSU to a portable power supply for traveling as it is reasonably small. To go with it I will also make up a visual indication as to the state of the PSU once on, this is to ...
2
votes
3answers
335 views

Up to ~1000 A constant current supply 10-40 VDC

So a little background to explain the need. Occasionally we need to test starter motors (for engines) and provide enough power when the load (engine) causes the starter to pull in excess of sometimes ...
0
votes
1answer
38 views

UPS makes sharp short-circuit sound when close to full depletion [closed]

I'm using a 1500VA Xpert UPS which supports my CPU (Cooler Master's GXII Pro 750W power supply) and Monitor (ViewSonic VA1703wb; 21W). The problem is that when the UPS is depleting (AC ...
2
votes
1answer
72 views

Building a wall-wart style case

I'm working on a project that will plug directly into the wall outlet, similar to a night-light or a wall-wart power supply. Internally, I'll use a AC-DC converter like this one. It has built-in ...
3
votes
4answers
123 views

How do you calculate the power factor of a power supply?

Is it possible to measure or calculate the power factor of a power supply without using expensive tools? If so how?
0
votes
2answers
59 views

Can I use lithium coin cell battery CR2320 for discharging about 80 mA at 3 V?

I need to use a coin cell battery as a source for supplying 3.0 V at about 70-80 mA for about 2 hr per day. The coin cell battery I want to use, its spec sheet doesn't tell me much about what I want ...
0
votes
3answers
103 views

48V DC Power Supply Using LM7812 in Series

I want to create a 600W 48 VDC power supply with input taken from the line (220VAC) and so far the steps that I've had in my mind are: Stepping-down the voltage to 15V using transformer with 3A ...
0
votes
0answers
55 views

How long will my ~20W device last with a 18000mAh battery?

I have a Mac Mini with a max power consumption of 85W but an average power consumption of ~20W (in my experience). I'm thinking of buying a portable power source with a 18000mAh battery. How do I ...
0
votes
1answer
37 views

Minimum limit for current and maximum limit for voltage while calculating power

I have a brushless Motor then i am using in conjunction with a ESC, powered by a Lithium Polymer Battery(3S 1300mah). I just got a new Lithium Polymer battery (6S 15000mah) from a friend and am ...
1
vote
2answers
53 views

Set ground reference of a 5v DC power supply to the middle of a 24v DC power supply

I have 2 isolated AC/DC power supplies. one generates a regulated 5 volt power supply and other generates a 24 volt power supply as you can see in the picture below: I also have designed a circuit ...
0
votes
1answer
44 views

Use DALI interface to power the device

I work on a DALI lighting system for home usage and I design all DALI devices from scratch. In this system, also a sensor module will be implemented. Since it will draw only a negligible current (app. ...
1
vote
3answers
171 views

Why can't different current sources connect in series?

I've posted different question similar to this, yet still struggling to understand the theory. So here is another attempt to understand as to way two power sources(with different currents) connected ...
-1
votes
1answer
50 views

Multiple power sources, each for a certain purpose? [closed]

In a circuit, there is somewhat of a symmetry of power sources being connected together. If they are of equal voltage they would be connected in parallel increasing current at the same voltage. Or if ...
0
votes
1answer
33 views

Can you use a SPST to turn on and off two power sources?

I have several batteries in series and the ground point is in the center, such that I can achieve a negative and positive voltage. The OP amp uses both negative and positive voltage. Let's assume I am ...
1
vote
2answers
110 views

Dual power supply without center tapped transformer

I am building a simple bi-polar power supply, that will be capable of -/+12VDC at around 1.25A. I have a mains transformer that brings 230VAC down to ~20VAC, with single windings on both sides. And I ...
-1
votes
1answer
81 views

Need to make a laptop charger [closed]

I am not an electrician. My laptop's charger burned when we had high voltage 2 days ago. My laptops charger says Output is: 19.5 V and 9.23 A. I am in a country that you can't easily find those kinds ...
0
votes
0answers
15 views

Charging batteries thru cigarette lighter [migrated]

The answer to this may be so obvious that I'm almost too embarrassed to ask; however, here goes: I have a high-end battery charger for my car which charges through the cigarette lighter receptacle. I ...
11
votes
2answers
838 views

What's the purpose of the full wave diode bridge in this DC-DC power supply?

In the following power supply circuit, there is a full wave diode bridge (full wave rectifier?) after the DC Input. I can see how we need a full wave rectifier after an AC input, but why after a DC ...
0
votes
1answer
61 views

Buck regulator AOZ1014 getting burned

I am analyzing a buck regulator circuit as shown in following figure. link for datasheet given here: http://aosmd.com/pdfs/datasheet/AOZ1014AI.pdf I have few queries in schematic: Q1. In above ...
1
vote
3answers
76 views

Connecting parallel DC loads

Consider the following power supply interface. I'd like to power a number [1,N] of bitcoin miners, 12V, 5A each one. question is: do red wires must be connected with V+ pins ? do black wires must ...
3
votes
2answers
176 views

12V supply to Vin Pin on Arduino

I'm trying to understand the following section of the Arduino Uno's schematic: (Here's a link to Arduino Uno R3 complete schematic) The Arduino's site recommends that Vin should be between 7 and ...