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

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0
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2answers
55 views

Charging supercapacitors with Buck converter. Do I need to cut power once charge is reached?

I am trying to build a supercapacitor charger, and as I don't particularly have a good handle on the risks of such a thing, I'm hopping on here to give some information. I am using a buck converter ...
0
votes
4answers
65 views

My thought on the reverse polarity protection

I am now designing a power reverse polarity protection circuit for my system. I found that most methods used for the protection would cause voltage drop in the power path. Even the MOSFET, which has ...
2
votes
2answers
410 views

Doesn't High Voltage Lead to More Power Loss

In India we use electric supply at 230 volts / 50 Hz whereas in US it is 110 V / 60 Hz. Since power loss in an equipment (say resistive heating element) is directly proportional to the voltage, ...
1
vote
1answer
31 views

Where should I place the capacitor in this TL431 + TRIAC crowbar circuit?

I'm building a replacement power supply for my C64 and want to add some protection against overvoltage. For that purpose, I tried to find a suitable crowbar circuit that would short-circuit the supply ...
0
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1answer
41 views

Help compare my results to the maximum power transfer theorem and explain using algorithms

So below is an image of the relationship between efficiency of a circuit and the resistance of the load, as you can see the maximum efficiency occurs when the two resistances are equal. here is a ...
-3
votes
0answers
43 views

How can I select proper power supply for underwater LED bulbs? [on hold]

Please help me select proper power supply (how to calculate total amps taken by all LED bulbs) to connect multiple LED bulbs (3W, 9W, 18W, 30W) in a line.
0
votes
1answer
47 views

Resistor values and power supply for super bright LED bulb project [on hold]

I want to make an LED bulb with five high power super bright white LEDs. Please tell me about resistors to use, and how do I connect all 5 LEDs (series/parallel)? Also, which power supply (volt and ...
-3
votes
0answers
48 views

Discharging a 10kV capacitor [on hold]

Please help me in designing a circuit to discharge a 10 kilovolt capacitor in PSIM software which works in continuous conduction mode and uses phase shift PWM control strategy to charge this 10 kV ...
1
vote
3answers
55 views

Would having no power supply but a large input signal damage the amplifier?

I am now learning about the power sequence of the circuit. And wonder that as every amplifier has its own limited input voltage (for example: ADA4004's input limit is V− < VIN < V+), would the ...
3
votes
0answers
164 views

What is the name of the cable inside PC cases? [migrated]

Due to limited linguistic and technical knowledge, I do not know (and can not find) the name for the 4 pin (or perhaps 3?) plugs that are used inside PC cases to deliver electricity. My questions: ...
0
votes
1answer
82 views

Running a low voltage stepper motor with a A4988 and 5V power suply

I got this little car I built using two of these motors and A4988 drivers. It was running with a 12V power supply, but I'm trying to get it on a battery and running for about 8 hours. thought I could ...
1
vote
0answers
72 views

Insufficient Power when using one power source vs two [duplicate]

So I've been working on a wireless remote relay switch using several components and have struck a break wall. The issue I'm having is that the D0 siginal output triggers the relay but only at short ...
0
votes
2answers
68 views

How is this 3 VAC power supply charging this 18 VDC battery? [on hold]

My cheapo 18V Black and Decker cordless drill recently died, and thinking I could maybe fix it, I took everything apart and then couldn't figure out how it was ever working in the first place! Here's ...
0
votes
1answer
41 views

Control relay from Bluetooth on ATtiny85

I know someone else has made a Bluetooth transmitter to a relay so i wanted to ask a few questions about it being possible? I am an almost newbie at electronics but i do know a few things, so first of ...
4
votes
2answers
368 views

Might swollen caps be working properly? [on hold]

I've seen these two swollen caps in a symmetric +12, 0, -12V power supply. The circuit (a theremin) seems to be working properly, but I don't know if that caps are going to cause damage in the ...
0
votes
0answers
71 views

6 Transistor Full Adder

I am working on a 6 Transistor Full Adder whose circuit diagram is The circuit works fine but there is a problem: it needs a 25k resistor at XNOR and SUM point to show the complete Full Adder ...
1
vote
2answers
47 views

Single versus split power supplies for op amps

Application is small signal (low mV). What are the tradeoffs between using a dual supply as opposed to single supply and virtual ground? Apart from maybe the cost of supplying a DC-DC converter to a ...
3
votes
3answers
127 views

Inductor selection for a switching regulator

This is somewhat related to this question, but hopefully a bit broader. I'm selecting components to fill out an lm2734. This regulator will take a 9-12V (11.1V nominal) input down to 5v @ 1A max. ...
2
votes
1answer
196 views

Please help me identify two pin locking connector

This is a two pin, locking style connector with "AMP" molded into the front edge; there is also a "P". Material is nylon or similar and the pins are pushed in from the rear like Molex connectors. What ...
-2
votes
1answer
74 views

Homework: Noise in a circuit [closed]

I had this problem in a homework assignment: If the noise in a 5 V voltage line and ground for a five volt circuit is of the order of 10 mV, for a first order system, how many time constants will ...
1
vote
3answers
36 views

Operation of PC817

I am studying a DC-DC converter circuit design which has PC817 photocoupler in it. I am confused with the way PC817 behaves. My friend says that it is an analog photocoupler. I have tested it myself ...
-3
votes
0answers
56 views

GOTTA CHOOSE WISELY [duplicate]

I have two AC adapters with the following specs: 1.- NU40-2120300-L1: Input: 100-240V~50/60Hz 1.2A Output: 12V 3.0A 2.- API3AD03: Input: 100-240V~50/60Hz 1.8A Output: 19V 3.42A The first one is ...
0
votes
0answers
50 views

Does the following power supply configuration make my device a safe and legal PELV appliance?

A small disclaimer up front: I am fully aware that advice from this site is not a replacement for a safety evaluation by an expert. I merely want to check my understanding of the rules and potential ...
-2
votes
0answers
38 views

Voltages and Current, which is important [duplicate]

I got my laptop adapter busted, it outputs 19V 3.42A, and I am not sure the reason why. My laptop takes in 19V but at 2A. Maybe the adapter was not the right fit. So I was thinking to build my own. ...
2
votes
1answer
99 views

5V Power Supply oscillates once another consumer is turned on

I live in Europe and we have 230V coming out of the power outlet. I have several consumers on one outlet: 5V DC supplies for Router, HDMI-Switch, Ambilight, one Computer, one Macbook and a fan). The ...
0
votes
2answers
70 views

How do I active the relays on this relay bank?

I purchased 2 "Mechanical Relay Board, 8 gang, 10A 220VAC, 24VAC 30ma coil" relay banks that I am trying to control from a raspberry Pi. To do this I've built out 2 595 shift registers and I'm using ...
0
votes
1answer
97 views

Oscilloscope ground and unit under test ground issue

I am working with an instrument which has a supply of 230V AC or 400V DC. AC source is isolated at the input via 1:1 transformer and DC source is a floating supply. I have a Yokogowa DL1620 ...
0
votes
2answers
64 views

Why increase in resistance of register used in circuit show lesser average power dissipation

I am working on 6 transistor full adder circuit. Red marked resistors (25k) are used to show all pattern of full adder correctly. But it show wired behavior. When I increase resistance from 25k to ...
0
votes
1answer
87 views

SC2272-M4 Behaviour when using relay SRD-05VDC-SL-C 5V DC

I'm currently encountering a problem when using a relay switch with a 5v receiver. When using the same receiver with a row of LEDS it works flawlessly. I've noticed that the relay keeps making the ...
0
votes
1answer
52 views

How to power an x16 PCIe card in an x8 slot?

In the cryptocurrency community, when GPU-mining was profitable, it was common for people to use ribbon cables to connect the graphics cards to PCIe slots. This lets one use more GPUs than there are ...
-1
votes
0answers
7 views

Spilled coffee on laptop [migrated]

Here is the story: When I woke up, I started my PC and went in the bathroom... when i came back i noticed that my keyboard is spilled with coffee and my laptop is turned off, I quickly wiped the ...
0
votes
1answer
76 views

Building a regulated power supply AC-to-DC [closed]

What components do I need to build a regulated power supply with an input voltage of 220V AC and outputs of 3V, 6V, 9V, 12V? Assuming max. current of 1A in each outputs.
1
vote
4answers
239 views

Why does TTL work with 5V, when there's no 5V battery?

It's a noob question, but every circuit I make uses 5V: 74LS uses 5V, ATMEGA328 uses 5V and so on. But in reality, everybody's designing circuits and shove a voltage regulator with 9V or 12V power ...
-1
votes
0answers
26 views

AC adapter input 220V output 4.5v DC 300mA [duplicate]

We are moving to Denmark and have a Pottery Barn kids Death Star painting with LED's build in that we would like to bring for my son. Here is a link: Currently it has an adapter that reads: AC ...
0
votes
1answer
76 views

5V DC 500 mA adapter run 100 feet to web cam

I am using a GUCE51 USB extender 100 feet from my computer to power a web cam. The extender uses a 5V DC 500 mA power supply. Option 1: Plug the power supply into the 110V AC on the inside and run 5V ...
1
vote
1answer
48 views

Switch current rating - actually current or really wattage rating?

I'm trying to build a dummy load for some power supply testing using some very large power resistors. Basically I will wire up the resistors in parallel and connect more if I want to decrease the ...
0
votes
0answers
82 views

grounding 2 different power supplies

I have 2 circuit boards I'm trying to connect together that each have a common 24 VAC source they are connected to. The problem I have is I'm trying to feed a switching 12 VDC signal to the one board ...
1
vote
2answers
88 views

Powering SIM 900 gsm

I bought a sim900 (the chip itself, not a module) and have gotten stuck trying to figure out how to power it. I hope to power it using a pin from my RBBB arduino clone, which outputs 5 volts and ...
-2
votes
1answer
46 views

Modify ATX PSU to output higher voltage [closed]

How do I modify my ATX PSU to output like 60V instead of 12V? I want to use it to power stepper motor drives
4
votes
1answer
73 views

What is the ideal way to handle data pins D+ and D- on a USB power adapter to be compatible with fast charging on devices?

I have found that many USB wall chargers use a resistive voltage divider to set the D+ and D- pins to a specific voltage, usually between 2 and 3 volts. Other USB wall chargers short the D+ and D- ...
0
votes
0answers
74 views

Wind energy (using 220V AC motor)

I have created a mechanical section of windmill generator but I am stuck in the power section. Knowing that I used ac 220V motor, how can I convert this unknown and variable AC voltage into DC 12V?
0
votes
0answers
49 views

Which type of power supply to equalize SLA battery?

I have some 6V SLA batteries wired in parallel and am wanting to apply a 7.5V (2.5V * 3 cells) equalization charge for a couple of hours. The problem is I'm trying to figure out which type of power ...
1
vote
1answer
63 views

How to choose what a power supply to drive 2 x 10watt RGB LEDS?

I'm trying to figure out how to determine what power supply I should be using for different types of LEDs for this and future projects. I have 2 x RGB LEDS: Forward Current: 350mA Forward Voltage: ...
5
votes
2answers
95 views

Two analog power planes for same voltage

I'm designing a board with LAN8720 and LPC1768. LPC's ADC and LAN's magnetics connections require analog 3.3V power. Should I separate these two analog power planes with a ferrite as I separate it ...
1
vote
2answers
45 views

Amplifier damage caused by failed power supply capacitors [closed]

MY QUESTION IS THIS: Would failed power supply caps cause peripheral damage to the amp, preamp or control circuits ? Supposedly there is "protection" for "DC offset, over current and over heat" I ...
0
votes
0answers
25 views

2.Can I use power supply with specs 'out: +5V - 2.5A / in: ~50-60Hz 0.5A' work with 'USB 2.0 HD 500GB’ requiring 'out: 5V - 2.5A / in: ~50-60Hz 0.4A'? [duplicate]

Info about external Harddrive (HD): https://www.lacie.com/support/support_manifest.htm?pid=11085 This is a different question than my 1st one. The difference is: - my 2nd Question: 'out: +5V - ...
-1
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0answers
20 views
3
votes
3answers
162 views

Why would the output voltage of a 5V SMPS (USB charger) increase with load?

I've been using a USB voltage/current measurement device to evaluate power consumption of USB devices and performance of USB chargers and batteries. Most of the USB power supplies I've used are ...
-2
votes
1answer
50 views

where can i find voltage sensors [closed]

I am shopping for voltage sensors to measure voltage between 0 and 300V and I cannot find a sensor which uses voltage supply of 5V . Any ideas I only have 5v suuply voltage
5
votes
1answer
109 views

How power system is designed for extreme small system, such as google contact lens?

I just read this news and got very curious: http://www.takepart.com/article/2014/07/23/goodbye-finger-pricking-how-googles-smart-contact-lens-really-helps-diabetics Google is designing "Google ...