Questions regarding the safe and effecient design and implementation of AC voltage to DC voltage supplies. Typically Mains to some lower DC voltage.

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1answer
33 views

DC-LVDT Output noise filtering

I am working with the DC-LVDT Omega 620-25 http://www.omega.com/pptst/LD620.html Manual: http://www.omega.com/Manuals/manualpdf/M4345.pdf Specs: http://www.omega.com/pressure/pdf/LD620.pdf I am ...
1
vote
2answers
77 views

Is a capacitive power supply safe?

I'm doing a home automation system which uses a RF transceiver(nRF24L01+) paired with an arduino to control the relays. Since these require low power DC to run I was researching on ac to dc when I ...
0
votes
0answers
25 views

LNK304 noise comes when using it's output

I've built a power converter with LNK304 for 230VAC to 5VDC. The schematic I've used is in the datasheet: http://www.mouser.com/ds/2/328/lnk302_304-306-179954.pdf at page 4, figure 5. First of all, ...
0
votes
3answers
30 views

Using thermal overload protection in AC-DC PWM motor driver circut

i'm having some difficulties with calculating the value of the thermal overload fuse in this circuit. The thermal fuse is used to protect the motor and the circuit behind it. The deal problem is that ...
0
votes
2answers
85 views

Isolated AC/DC Buck Converter

Why are there no isolated AC/DC buck converters around? For applications < 10W (say 5V/1A output) and mains input (85 - 264VC), is it feasible to use a standard buck circuit but add a 1:1 ...
1
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0answers
71 views

12VAC to 12VDC Converter Requirements for RGB LED Controller

I have an outdoor lighting transformer (operating at the usual 12VAC) that I want to add a strip of LED lights in a new run. The transformer has two legs, each ...
1
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2answers
220 views

Purpose of capacitor across transformer in AC-DC power supply? [duplicate]

I have been looking to buy a AC-DC 5v power supply module to power a mains relay in a circuit I am making. I came across a couple of different models on eBay and am trying to understand their basic ...
0
votes
2answers
84 views

AC Adapter gives much more voltage than it's supposed to [duplicate]

Hello! I have this one older AC-DC adapter from Korg (wallwart?)... ...that I have been using for my (guitar) effect pedals for a few years, and I recently found out (when I was doing some ...
0
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1answer
56 views

Use 5w/3w 12vdc LED on 60w 12vac cdi ignition

I'm building a vintage two stroke race bike out of a 78' puch maxi. The original points setup is junk and I'm switching to a CDI. I have an LED headlight that I'd love to use for aesthetic purposes. ...
-2
votes
1answer
59 views

Connecting two DC voltage sources in series

I need a 42 volt DC supply to check a motor. All I have is one 30V DC source and a few rated lower than this. Is it possible for me to connect the 30V source and a 12V source in series to get the ...
1
vote
1answer
58 views

Power adapter efficiency standards, any drawbacks?

Supposedly, some new federal regulation is imposing "energy efficiency" standards on small power adapters. How is this going to affect electronics? Are the old types of adapters going away? If so, ...
2
votes
1answer
41 views

Battery charger output power higher than input?

i would like to ask about battery charger i saw at work :) the plate on charger says: Input voltage 3 phase ac Min 400v Nominal 400-415v Max 456v Input current 20A Output 110v DC 9kW 28v ...
0
votes
3answers
301 views

220 AC to 220 DC Converter

I am designing a circuit that will give me an adjustable 220DC voltage. The load is approximately 2kohms, so the maximum current that will flow is 100mA.And I have design restrictions, it needs to be ...
0
votes
4answers
104 views

Oscilloscope and main earth reference

I have AC/DC 3/6/12V out universal adapter with two pins (without earth connector) and would like to use it for powering my arduino project and playing with oscilloscope. Knowing that my oscilloscope ...
0
votes
3answers
156 views

Need to build a compact power supply that runs off the 240V socket and provides 12V, 5V and 3.3V for an Arduino Project [closed]

I want to have an as-compact-as-possible (but no limit on size) power brick/supply that takes power from a UK Wall socket and has multiple outputs with different voltages. Need 12V@2A for stepper ...
0
votes
1answer
62 views

input current vs output current

My old/new laptop adapter specs as given below. I understand the output current for new is 4.5A which is OK when compared to old which provides 3.25A load since it can provide more load. However, ...
0
votes
1answer
57 views

Using AC-DC converter Module

I am trying to use an AC/DC converter module developed by third party. In the data sheet, I see following Is there any way I can do both at the same time?
1
vote
1answer
109 views

Why there are AC timing characteristics but not DC in I2C interfaced chip?

I'm quite newbie in electronics, and I'd like to learn why there are AC timing characteristics to this particular EEPROM (24LC512) that I'm using but none for DC? Does AC timing constraints apply to ...
0
votes
1answer
86 views

2 AC to DC converters in series problem

Hello, I am a beginner at electronics. I have two AC to DC converters ((3),(5) in image). The converter with the number 3 is connected parallel with my room's light bulb. It converts 220v AC to 12V ...
0
votes
2answers
149 views

Is there a reason why some ac/dc adapters don't have a grounding pin?

I'm searching for an AC/DC adapter of 6v 300mA, but I can't find one with a grounding pin (E-type). Is there a specific reason for this?
0
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3answers
158 views

link voltage and link capacitor basics [closed]

I am currently getting into the topic of electric vehicles and I often come across the terms link voltage and link capacitor. simulate this circuit – Schematic created using CircuitLab ...
-3
votes
1answer
69 views

Computer Power Adapter Proper Volts No Amps [closed]

I have a 4 month old laptop. The other day it stopped charging. When I meter it shows 19.94 volts and 0.0 amps. Specs call for 19.5 volts and 2.31 amps. So the manufacturer (HP) is sending me a new ...
0
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2answers
332 views

How to plan my LED circuit, voltage, and resistor

The LED emitters in my outdoor lamps blew out and I need to replace them but I have to rebuild the emitter from scratch because replacement parts are not available. The whole lamp was made in China. ...
5
votes
2answers
910 views

Why are PCB-mount AC DC converters so expensive? [closed]

In a thrown-together prototype, I used a few wall warts to get the various voltages I needed. Now, I'm trying to build a cleaner version with a single plug and put it all on a PCB to eliminate my rats ...
1
vote
1answer
135 views

Need help with stepping down DC volts

I don't have much experience with electronics, I'm simply trying to get (at least what I think) is a fairly simple circuit running. I've got a blower fan that I need to get running. It uses 12VDC at ...
0
votes
1answer
564 views

How to convert low voltage (< 0.4V) AC to DC

I've made a mini generator for a mini wind turbine. An oscilloscope voltage measurement shows a +0.4/-0.4 V sinusoidal AC current. I'd like to convert it into DC, in order to put a charge and detect ...
2
votes
0answers
183 views

Can AC/DC conversion losses from solar panels be avoided with a Tesla Powerwall?

(background: I'm just playing with numbers, trying to estimate how many solar panels would be needed to fully supply the energy for a home and 2 Tesla cars) I've been reading up on solar panels and ...
2
votes
1answer
92 views

Transformer and a relay in series - but function like in parallel, but not exactly

I've been doing some planning to build a home automation system on top of the existing power infrastructure of my house. The first thing would be making my light switches smart. My original plan is ...
0
votes
1answer
217 views

Simplest AC-DC: charging capacitor at needed AC input voltage

To implement a simple AC mains input circuit to charge a capacitor with low voltage DC I think that it should be possible to connect the output capacitor to the AC line through a diode, and a ...
2
votes
3answers
352 views

Feasibility of very high temperature ac-dc switching power supply

I'm involved in a product design (on the mechanical side, to be clear that I'm not an EE) where we need a very compact ac-dc switching power supply that will take 90-300vac, 50-60hz and output 5 watts ...
2
votes
1answer
490 views

wiring AC switch with DC led

This is a follow up to a previous question I had answered. I'd like to show the following diagram. Here, I have laid out (crudely) a diagram that has 120v-110vAC from the wall going to a push ...
1
vote
1answer
75 views

'Dielectric Strength' parameter meaning for cheap inductior coils

Initially I need an inductor to be used in cheap low-power AC-DC power supply. I'd like to use LNK304 solution: When I reached 1mH coil I found Bourns 77F coils: very cheap (only 8 cents at some ...
0
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1answer
3k views

5 pin push button switch with LED AC wiring question

Thank you in advance for any help you can give. This is really my first project like this. I built a shelf in my house based on this picture. and I'm integrating an Eddison bulb lamp into the ...
-1
votes
1answer
89 views

Does order matter when it comes to AC power? [closed]

Is there anything about electricity or the electrical design of AC power strips that dictates in what order the devices should be plugged in? When I say, "in what order", I am referring to the ...
-2
votes
1answer
73 views

Is there a rightside up when plugging in an AC to DC power converter? [closed]

When plugging an AC to DC converter into an AC outlet, does it make any difference at all if the wall wort is "upside down" or "rightside up"? Is there anything about the electrical design that would ...
0
votes
2answers
279 views

Convert high voltage AC (10kV, 60Hz) to low voltage DC (5V)

Is there any easy and safe way to convert the high voltage AC (60Hz, 10kV, such as the voltage on the overhead line) to 5V DC that can be used to power up a micro controller (around 1W power)? We do ...
2
votes
1answer
474 views

AC-DC Adapter - Output lower than rating and what's this 'cont' output for?

I have a Canon AC adapter, Model K30321, that I'd like to use in a project. I'm attempting to test the adapter for correct voltage output. Adapter specs: ...
1
vote
1answer
300 views

Is a charged capacitor in a power supply dangerous?

I'm just beginning in hobby electronics and have made a power supply with a bridge rectifier and a smoothing capacitor (4700uF). I want to put a toggle switch in to turn the supply off and on. Should ...
1
vote
2answers
331 views

Parallel connection between distinct DC Bench Power Supplies

I'm using a 30V DC power supply which is said to be 30V/3A with a switch between series/indep/parallel mode. Connecting the supplies in parallel, we have a maximum of 6A. However, in order to execute ...
0
votes
3answers
208 views

Converting small AC output voltage of a piezo element to DC without IC

I've been trying to find a AC to DC converting circuit that will take a piezoelectric crystal as its input. I have the piezo to a bridge rectifier but all the diagrams I am finding have some kind of ...
1
vote
0answers
50 views

Why do some Arduino relay modules can handle up to 250 VAC but not above 30 VDC? [duplicate]

When you look for "Arduino relay module"s, you usually see one form "SONGLE" that says on it: 10A 250 VAC 10A 125 VAC 10A 30 VDC 10A 28 VDC My ...
0
votes
1answer
159 views

AC DC adapter voltage regulation

I would like to make a dimmer for several ikea desktop LED lights. This one is plugged on a LED driver (adapter) with specifications: Primary:220-240VAC 50/60Mhz, 0.06A Secondary: constant current: DC ...
2
votes
2answers
143 views

Replace transformer with PWM control

This is my first question on stackexchange so if I do anything wrong, please let me know :-) So my situation is the following: I am working on a power supply module where I need 7 separated +28V DC ...
0
votes
1answer
167 views

AC - DC Power Supply Non Isolated

I have been thinking of using LNK305P from Power Integrations to integrate an AC -DC power supply in my next project. The application note containing the circuit is here. What things do I need to ...
1
vote
2answers
699 views

Converting 100mV AC to 1V DC

Hey guys I am looking for a circuit where I can convert 100mV AC to 1V DC and then feed it to my microcontroller's ADC pin. Can any one suggest any circuit to achieve this? I want to interface a ...
1
vote
1answer
284 views

Why are some AC/DC adapters light while others are heavy?

I was browsing the thrift store and found a nice pair of JBL 2.0 computer speakers, but they lacked a power adapter. They call for a 12V 1A supply. I have a ton of "bricks" lying around, but no 12V ...
0
votes
1answer
789 views

Looking for circuit diagrams of current mobile phone chargers [closed]

I am writing an investigation into how a mobile phone charger works and I'm required to break down the internals with a block diagram with component explanations. To help get me on track I'm looking ...
7
votes
3answers
294 views

Connecting two DC wallwarts in series - to produce dual DC supply

I have two 9 V, 300 mA wallwarts and would like to connect them in series to produce +9 V, 0 V and -9 V. This can be done with two 9 V batteries (as seen below), but can I do this with two ...
1
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2answers
788 views

AC DC circuit mixed. Voltage at a point

I'm Computer Science student and I'm having a hard time understanding this task: Answer is: Va for DC = 0V, Va for AC = -1 - 3j Vb for DC = 4.8V, Vb for AC = 1 - 1j I have a couple of questions ...
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votes
1answer
127 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 ...