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
62 views

Will the use of an AC relay keep my power supply isolated?

An isolated power supply is used to convert 120 VAC 60Hz power from mains to 12V. A linear voltage regulator then converts the 12V to 5V. A 5V micro-controller is then used to switch on a 12V relay (...
3
votes
3answers
768 views

Will a fuse improve the safety of my non-isolated buck converter design?

I have a power circuit that implements an AC-to-DC rectifier and a non-isolated buck converter to convert a 120 VAC 60Hz signal to 12V and then a linear voltage regulator to step the 12V down to 5V. ...
1
vote
2answers
32 views

Does the transformer in this circuit cause a voltage drop to the DC motor?

In this circuit: Is the transformer and the circuit on the secondary side of the transformer only there for the test-point or does it affect the voltage to the DC motor? The DC motor is a 90V motor ...
0
votes
1answer
33 views

What does “Transient Response Recovery” means in the output specification of a AC-DC power supply?

I'm using a AC-DC power supply to provide 24VDC input to a PCB. A 100uF,35V tantalum is used as one of the filter capacitors for the 24V(same from supply) input of DC-DC regulator on PCB. In some ...
0
votes
2answers
96 views

How is this device getting low voltage?

I've opened up a Lutron dinner, and I'm trying to understand how the microprocessor gets its DC voltage. With my limited knowledge I'm not seeing an AC/DC converter. I've attached pictures, can ...
0
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2answers
261 views

Multimeter reading 0 and drawing too much from DC power supply

So I've got a circuit that requires both 5V and 3.3V so I bought a 5V 2A AC/DC converter from a store, which I will add resistors to later for the 3.3V. Before I connect it to my circuit, I wanted to ...
0
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0answers
19 views

120V ac to normally open alarm signal

I need to monitor the status of our commercial AC supply and the status of our two diesel generators, for this I need to generate three alarm points that will go into our building alarm system as ...
-1
votes
4answers
204 views

How to convert 700V AC to 5V DC 500mA?

I have a device that requires approximately 500 mA at 5 VDC, and I am required to get this power from two legs of a three phase power supply. The voltage between these legs can be between 110 and 700 ...
2
votes
2answers
59 views

What are the safety and device risks associated with not connecting the grounding prong on a 120V AC device?

For example, imagine a device that comes with a 3-prong (grounded) AC plug. What are the risks associated with, for example, plugging this device into a 2-prong extension cord which effectively ...
1
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2answers
123 views

What are design considerations for grounding an enclosed AC-to-DC converter?

Here I'm talking about a device that takes 100-240V AC in, and outputs 10-20V DC out. In terms of grounding, I'm referring to the grounding offered by a standard outlet (e.g., a NEMA-5-15R receptacle)....
1
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2answers
93 views

Can I use a Triac dimmer circuit to control the brightness of an AC powered LED light strip? [closed]

I am using this Triac circuit to control the brightness of several incandescent lights. The circuit monitors the phase of the 120 volt wall current, then signals an Arduino when the phase crossed ...
0
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0answers
24 views

LNK306 based +/- 3.3V AC-DC power supply does not work right

I've been trying to design a power supply using PI's LNK306 using the datasheet and this application note. On page 10, the app note lists how you can create a +/- rail for the power supply. The note ...
0
votes
1answer
46 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
84 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
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0answers
35 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
47 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
100 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
90 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
vote
2answers
390 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
97 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
votes
1answer
64 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
74 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
60 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
43 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
388 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
120 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
183 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
71 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
130 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
96 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 DC ...
0
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2answers
178 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
186 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
73 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
votes
2answers
373 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
931 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
153 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
611 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 ...
3
votes
1answer
220 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
235 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
403 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
547 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
79 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 ...
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votes
1answer
93 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
80 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
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2answers
312 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
604 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
317 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 ...