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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1answer
7 views

Is it possible to use Ultrasonic sensor HC-SR04 in continuous power-on mode

I will be using Ultrasonic sensor HC-SR04 in water level measurement. I will be triggering the US sensor and getting back the time-pulse from it at very slow rate maybe once every minute. I want to ...
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0answers
29 views

How to calculate a UPS run time?

I have a laptop with a charger with (20V/6.5A) output. And also a 22" extra monitor with a adapter of (12V/3A) and a 4G modem with (12V/1A) adapter. I want to know if I want to have at least 5 hours ...
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2answers
36 views

ATX Power Supply Minimum Load

I know this is a commonly asked question but most of the answers I got are more than 5 years ago. So basically, My friend found a ATX power supply and was gonna give it to me. Since I already have a ...
3
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1answer
32 views

Connecting negative terminal of DC power supply to negative terminal of other DC supply

I'm wiring up an electrical box that has several sensors, relays and a PLC. The PLC and relays are powered with a 24Vdc power supply. The sensors, which provide an analog input to the PLC, are powered ...
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2answers
785 views

Efficiently limit current to led without power loss

Let's assume I have 3 Leds which have forward voltage of 3.3v and current rating is 300mA. All the leds are in series and I have a power supply of 12v. when I series a resistor to limit current it ...
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1answer
28 views

Isolated power supply with output on a 2kVDC floating ground

I am building a system of detectors which are referenced to independent floating grounds. The maximum voltage between each stage is 2kVDC. So I need isolated supplies which can operate continuously at ...
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2answers
19k views

Converting universal AC to 3.3v DC @ 0.1A

There's a bunch of topics around this but i haven't found something that fits my requirements. I'd imagine this is a fairly common thing though so any pointers would be appreciated Basically i want ...
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1answer
47 views

Designing a 6V --> 40V step up converter

I need to design a step up converter with the following requierements: Vin = 6V - 8.4V Vout = 35 - 40V, Iout = 2.5A Could anyone give me some insights on how to ...
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0answers
39 views

Changing the target voltage of an lm7812 from 12V to 10V [duplicate]

The lm7812 won't start regulating until the input bypasses 12V. I want it to be regulating starting from 10V. so if the input is 11V, the output should be 10V. (behaves like an lm7812) I read that ...
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3answers
85 views

What power adapter do I need to charge a 7.2V 4000mAh battery that I made?

I made a Ni-CD 7.2V 4000mAh battery. What power adapter do I need to charge it? How many volts and how many amperes should the adapter output? Each battery cell is 1.2 volts. I have a 9V 500mA ...
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3answers
58 views

220V/1ph/60Hz equipment to operate on 208V/3ph/60Hz

Can an equipment built for 220V/1ph/60 Hz be connected to a 208V/3 ph/60Hz grid by using only two lines of the 110V each across the load?
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1answer
1k views

How many Watts?

I live off -grid and have 12 volt solar system with a 500 watt inverter. I need to find out how many watts my speaker /amplifier/docking station uses. Im usually good at figuring out watts..but this ...
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0answers
49 views

Power Supply - 2x output cables, joined at common rail

I have a 24V 25A power supply providing the juice to my 3D printer but it's a cheap LED driver and it's noisy - it's just the fan but as it's at home it's annoying. I'm looking to replace it with ...
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0answers
60 views

Changing the target voltage of an lm7812 from 12V to 10V [on hold]

The lm7812 won't start regulating until the input bypasses 12V. I want it to be regulating starting from 10V. so if the input is 11V, the output should be 10V. I read that by putting the ground to a ...
0
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1answer
53 views

Variable bench power supply from multiple PSUs? [on hold]

I have 6 identical server power supplies that put out 12 volts and 25 amps each. I'd like to repurpose them to make one big variable bench power supply. I figured out the pin outs to power them on ...
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3answers
2k views

Deciding between 7.4V and 11.1V power

Suppose I had a unit that could accept DC power between 6 and 14 volts, and the choice of using either a 7.4V 1000 mAh or 11.1V 1000 mAh battery. Do either of these choices offer a clear advantage? ...
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1answer
48 views

Which Comparator could match this electronic circuit?

Below is a schematic of a current regulator using a comparator IC2. The board is from an XP-605 ELENCO bench top adjustable power supply. Searching the WEB was unsuccessful in finding any original ...
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3answers
87 views

Designing reverse and overvoltage protection at 3.3V

I have a barrel jack powered design that I'm making, but I would like to prevent damage in the case of reverse polarity (sleeve is positive instead of negative) and overvoltage (plugging in a 12V ...
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1answer
35 views

Board mount AC/DC converter design concerns

I'm going to use board mount power supply (IRM-30-12) for first time. It has class 2 protections as per datasheet. Does it really protect my digital circuit in case of Hazardous situations like ...
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1answer
35 views

How to power multiple devices to a single Lipo battery [on hold]

I am trying to power my quadcopter following the instructions listed here. My power source is the MultiStar LiHV High Capacity 10000mAh 4S 10C Multi-Rotor Lipo Pack. Using this battery, I aim to ...
1
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2answers
1k views

LM1875 bridged amplifier at 12v?

I am trying to build 5-10W amplifier. The minimum voltage for LM1875 is 16v but 12v is not far from it. Where I am getting lost is whether I am going to get at least 5W when the amplifiers are ...
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1answer
45 views

AC noise to electronic circuitry

I find some random issues that is still unknown. I'm using mean well SMPS 12v, 3A for supply and charging 2 cell battery 7.4v with a charging current 1.2A. The supplies are parallel which is switched ...
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0answers
51 views

Noise in portable power supply to guitar effects pedals

I am constructing a battery powered power supply for a guitar effects pedal board. There are 5 pedals and I am using a phone charging battery and a boost converter to supply 9v ( centre negative ) ...
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1answer
33 views

LED Strip - Voltage Drop when Wired in Parallel

please have a look at this chart: I have a question on the calculation of voltage drop on each of the connection point between the wire and led strip. We are using 1.5mm2 wire and 24V led strip which ...
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2answers
47 views

Recipe for Stepping Down DC Voltage from 19V to 12V w/ Low Inrterna Resistance

I need a good 12V power supply from time to time. There are a lot of good laptop power supplies around that can give out about 5A. Is there a good, proven recipe out there that can do the voltage ...
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6answers
23k views

How to convert AC to DC

I am designing a circuit that needs to output 5VDC @ 1A. I'm trying to use a wall transformer to step the voltage down to 12VAC. The next step is the diode bridge and ripple capacitor. The ripple ...
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2answers
93 views

Why does this 5 V power supply work and the other one doesn't?

This is my first post here, I hope I'm in the correct area. This is my problem, I bought this circuit to receive caller ID over protocol DTMF. I have a few 5V power supplies here, (0.45A ,1A and 4....
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1answer
89 views

What's the purpose of a diode across capacitor after voltage regulator?

I'm learning about power supplies at university and I have created 2 or 3 PCBs of this stuff, but recently I saw this schematic: I have no idea of what exactly these diodes do in this circuit. Can ...
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0answers
55 views

Kitchen scale claims low battery, but works on power supply [on hold]

I'm trying to help someone repair a kitchen scale, and have run into an interesting problem (at least to me - full disclosure, mechanical engineer who struggled through basic circuits, etc.). On ...
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4answers
124 views

Adjustable Power Supply with LM317

I want to create an adjustable power supply for my electronics projects, and the cheapest/fastest option seems to be using an LM317. However, I do not want to blow things up by doing something wrong (...
2
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3answers
75 views

Dim LED lamp with constant current power supply using resistors

I own a really bright led lamp that I want to dim. It is powered by a constant current power supply that can supply 37mA between 11V to 17V. If my lamp is connected the voltage settles at 13.58V. ...
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2answers
118 views

Can a stripped USB charging cable electrify you and how dangerous would it be? [on hold]

I have a USB type C charging cable that I charge my cellphone with. Couple of days ago I found out that it got frayed on some parts of its plastic cover. I always charge my cellphone in bed and before ...
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2answers
56 views

What’s the difference between a power supply, a buck converter and a step-up booster? [closed]

Do these words mean very specific things? Are they all the same? What are the defining factors?
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1answer
63 views

What is (was) this component at ZD102 (top left, next to powered serial connector)

Part at ZD102 is overloaded with too much current and blown. It's three legged, with two legs on the south side and 1 on the top. The left side (white in the picture) is blown and has since ...
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1answer
93 views

Power bank DIY Build( Regarding protection circuits)

I have been toying with the idea of making a power bank as I have a few old laptop batteries lying around which are still working well. I plan to use these components: Constant current lithium ...
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1answer
26 views

24V 3D Printer - power ratings

I have a 3D printer at home and looking to improve some parts. The PSU on the printer has no labels so I'm not certain what it's doing - but the 3D printer's spec. sheet says it's 600W peak and it ...
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2answers
59 views

What is the series resistor doing between the power source and the power input of this IC?

This is from an Adafruit RTC module. What purpose is the R3 1k resistor serving in this circuit? Is this a RC charging circuit? Would the capacitor C1 not get any charge if the resistor wasnt there? ...
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1answer
154 views

Do you know how to add VEE and VCC power strips to op-amp in Cadence that will be fit for simulation?

This is the built in Cadence OPAmp. I need to add A capacitor to the VCC wirep and Ground the VEE wire however, there is clearly not a VEE or VCC on this op amp. Also, I know that I could manually ...
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2answers
1k views

Power microcontroller from super capacitor

I have a uC that works with 1.8V up to 3.3V. Current consumption is at about 20uA in sleep mode and about 12 mA in active state. The uC will enter active state for about 100 ms every minute. So I am ...
1
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1answer
137 views

How to design for electrical connection for a food dryer

I am on this project in building food dryer to dry 2 kg fish cracker maximum per use. Based on the calculation, I only need to use power of approximately 60 watt for the heating to achieve the energy ...
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0answers
36 views

Wemos D1 mini doesn't boot with common ground with PZEM-004t

I'm experimenting with Wemos D1 mini and PZEM-004t to monitor my home electricity, but I'm having a strange issue. I'm trying to supply PZEM-004t independently from a Wemos with a dedicated AC/DC 5V/0....
2
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4answers
56 views

Isolated Power Supplies for Inverter Gate Drivers

I am using a 3-Phase IPM IGBT Inverter Module in motor driver. This module has built-in gate drivers which require 4 Isolated power supplies for their operation. In all I have to design 5 Isolated ...
5
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2answers
2k views

Power Supply Diode Keeps Burning Out

I am trying to replicate the circuit I found here: (source: cogeco.ca) This is a photograph of what I have built: In my photo I have labeled one diode in the bridge rectifier which has burn out ...
3
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3answers
216 views

Why aren't non-isolated DC-DC converters made for high wattage applications?

I am new to electronics. I am presently studying DC to DC converters. One thing I noticed is that most of the people are using isolated stepdown converters like half bridge, full bridge, or resonant ...
2
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3answers
202 views

Understanding this power supply design

I'm doing some kind of reverse engineering to this very old power supply design. I'm having hard time trying to understand it all. I'm asking for some hints that help me read this schematic. From this ...
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0answers
41 views

EE go pro watch pogo cable [closed]

Hello I have a EE go pro watch but not the pogo 4 pin cable to charge it can one be made as EE don't have replacements that ks
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1answer
88 views

Resistor and power supply [closed]

A 1.5kohm resistor has a power rating of 3.75W. if it is connected to a 24V power supply, will it be damaged? why?
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0answers
29 views

Wiring high voltage transformers in parallel [on hold]

I have 2 high voltage transformers from microwave ovens , both transformers are exactly the same.I need to wire them in parallel can anybody tell me how to do it?
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1answer
117 views

Powering Atmega, DAC and Bluetooth in Car

I'm looking for a proper power supply schematic which would fit my needs and would have all required protections (overcurrent, overvoltage, reverse current, etc) for use in car. I want to power Atmega ...
0
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3answers
264 views

Phono preamp, one channel doesn't work

I have built a stereo preamp using this circuit (taken from here Hi-Fi Phono Preamp Rod Elliott - ESP), but for some reason I can't get the right channel to work at all while the left one plays. Now ...