A transformer couples two or more AC signals through a magnetic field. Often used as galvanic isolation and to transform one AC voltage to another.
2
votes
3answers
70 views
balun transformer design
The schematic shows a balun (unbalanced i/p to balanced output).In the design one condition is input impedance must be equal to output impedance since its 1:1 transformer and it has to follow ...
4
votes
1answer
85 views
How do European to American outlet change frequency?
So for the transforming of voltage, a transformer could get a european outlet from 240 to 120 volts. How do these switch the frequency though, do they have to convert it into DC and then generate a ...
1
vote
1answer
77 views
Can Power be absorbed by large transformers?
Nearby our house is a transformer for underground power lines. It sort of looks like this:
When I take a telephone pickup coil, and amplify I hear the 60hz hum through a speaker. I am wondering if ...
0
votes
1answer
74 views
Flyback transformer
Recently, I posted a question about a flyback transformer schematic I was having.
If you didn't check the link, I was having problems with the frequency of the 555 timer as well as problems with ...
1
vote
4answers
132 views
Rectifying induced current without using any semiconductors
Consider a 1:1 transformer.
Short DC pulses are applied to the primary (input) coil. Once it's positive current pulse, once it's negative current. It's not strict alternating current (i.e. two ...
1
vote
2answers
87 views
Flyback transformer - ambiguous schematics and other issues
I'm currently using schematic for a flyback transformer.
As you can see, there's a big problem - neither the schematic, nor the website describing it, give the value of the capacitor. It says ".01", ...
0
votes
1answer
26 views
Post-Transformer RMS Voltage for This Circuit?
I am confused here. For the below circuit:
simulate this circuit – Schematic created using CircuitLab
Ripple voltage is given as 1V peak to peak, Vo = 15V DC. I have assumed a 0.7V drop ...
0
votes
3answers
69 views
Transformer for Flyback power supply
I am designing an isolated DC-DC converter with an input of 12V and an output of 5V@12A, at the moment, a flyback seems like the best option. I have read several books regarding the subject and I am ...
-5
votes
0answers
27 views
Transformer design for a rectifier Circuit [closed]
what is the KVA rating of transformer required for a 460 V,2000 Amps rectifier unit for Galvanization?Also please specify the cable size required.
8
votes
1answer
109 views
What is the function of this choke-like transformer on the PCB side of this RJ45 jack+magnetics connector?
I came across this ethernet jack+magnetics connector the other day and was wondering what the transformer on the PCB side was for. I thought it looked like a choke, but there is a centre tap running ...
-4
votes
0answers
33 views
12V halogen pendant lamp [closed]
I have a hanging ceiling pendant lamp with three seperate hanging pendants. They are each 12V 50 Watts bulbs. Two of the three have died(at different times), i tried to swap the good bulb (and also ...
0
votes
1answer
90 views
How to power “arduino” from wall?
So I have a fake "arduino" that I put together (The main components on a breadboard, i.e. ATmega328, capacitors, ocilator, etc) and I am trying to use it to overide a light switch (When the light ...
0
votes
1answer
56 views
Help With Paper Calculation for Peak Rectifier Design Problem
I am tasked with designing a circuit for the following particulars:
A peak rectifier will be used as part of a DC power supply to supply an average DC output voltage of 15V, with maximum +/- 1V ...
-6
votes
2answers
65 views
If i change the transformer on my inverter for a bigger one, will it increase the watts? [closed]
If i change the transformer on my inverter for a bigger one, will it increase the watts?
1
vote
1answer
100 views
Why is maximum flux attained in transformer when off load?
Can anyone explain to me why the maximum flux in a transformer is attained when off load?
What happens to the flux when on load? Are the flux from the secondary load current and primary load ...
3
votes
2answers
142 views
Reactance / Inductance / Impedance of a 1:1 Transformer
I've searched around and poored through what references I have available, and haven't been able to find an answer to this question.
Regarding 1:1 transformers, I found a website where an audio ...
-2
votes
0answers
65 views
Is there a transformer that could replace the component: Conrad Electronics type 516260-62? [closed]
The original question posted was 'on-topic', but I will reformat and add the necessary specifications. I am inquiring about a replacement part for a transformer that has already been mentioned in a ...
0
votes
1answer
117 views
Effect of an isolation transformer on leakage current
How do isolation transformers affect the leakage current through protective earth in a system?
Scenario 1: Mains is directly connected to circuit. Metal enclosure has a protective earth connection ...
1
vote
1answer
90 views
How will the output of a 12V transformer wall wart differ from that of a 12V SMPS brick?
I have been working on a project to drive an electric door strike from an Arduino shield of my own design. Actually, I'm using a Freetronics Eleven and not an official Arduino, which is relevant ...
0
votes
1answer
50 views
what transformer should i use? [closed]
OK, i am new at all of this and for my first project i desided to try to use the power from a coal (like the ones you sprinkle incense on), use a Peltier to convert the heat to dc, now i know i need ...
1
vote
1answer
66 views
Live-Neutral transformer fault
In this critique of an ELV PSU design, it is suggested that a "Live-Neutral" fault could result in a fault current of thousands of amps. I'm sceptical. Please could someone explain how this could be? ...
2
votes
1answer
60 views
How to measure the VA rating of a step down transformer
I have an uncased, unlabeled step-down transformer which converts 240 UK voltage to 112v (I have measured this with a meter). It weighs 1.5kg, is 10 x 8 x 10.5cms including the attached 2-pin US ...
2
votes
1answer
65 views
Is NRTL approval required for the sub components I purchase and assemble into a final product in order to sell the product in USA?
I manufacture a lighting product made up of components I purchase and then assemble into a housing and heat sinks that my company manufactures. The components I assemble include an electrical driver/ ...
3
votes
1answer
82 views
How to pick a Push-Pull Transformer?
I have to admit up front this is a borderline shopping question. But the fact is I'm looking at an application note from Linear Technologies. That application note calls for Coiltronics CTX02-14659 ...
0
votes
3answers
109 views
transformer for power supply
i bought this transformer to use in a power supply http://www.dhwelectronics.com/Safety_Isolating_019000600020/P028_1A_Secondary_30VA_Transformer_With_15015_Vac_Ouputs/
i want to have two outputs but ...
0
votes
2answers
42 views
Need some CCFL transformer help
I was wondering about these transformers. It says it requires a DC input (I think) however don't transformers need an AC input, and if so does that mean I would need to make an oscillator circuit to ...
3
votes
3answers
206 views
Dots in a transformer symbol
I came across this schematic:
What do the dots in the transformer indicate?
5
votes
3answers
302 views
Ethernet connector and transformers
I'm working on an Ethernet connection for a PIC18F4620 with the ENC28J60. I found a useful article here, with a schematic:
I see I need transformers between the RJ45 connector and the Ethernet ...
3
votes
3answers
165 views
Building a power supply, want to stay alive
I am building a power supply for a very old laptop. The circuit uses a transformer (220 V primary to 15 V secondary, 33 VA) and that worries me a little. (Please note that I an enthusiast and so far I ...
3
votes
2answers
158 views
how do they make travel adapters so small?
How do they make cellphone adapters, especially "travel adapters", so small?
I once peeked inside an old Nintendo adapter, and it had (among other circuitry) a rather-bulky step-down transformer to ...
0
votes
1answer
92 views
Ground Fault Question Regarding a 3 Phase Circuit
I'm needing to design a 3 phase ground fault detection system for a 480V system. It will need to be able to trip when there's ground fault current >1A.
I have done some reading and it sounds like ...
-2
votes
3answers
86 views
Converting voltage to amperage [closed]
I was wondering if power transformers can be used to convert a high-volt/low-amp AC to low-volt/high-amp AC.
For example:
AC power input (E±=100 I=1) to a transformer primary (100 windings) and ...
0
votes
1answer
70 views
Getting the right converter for this 110/120v device, where the power is 220/240v
I have an appliance designed for 110/120v. It says it runs peak at 1200 watts, but I can't find yet any mention of Amps. I'll be using it in Europe at 220/240v, if it is possible.
I understand I can ...
-3
votes
1answer
163 views
Can I pull ampere out of transformer as I want not as my circuit need?
I have transformer with max ampere 20Amp, If I tried to charge 12V battery with it, it gives 2Amp..I want to do something that force transformer to gives 10Amp for example...Is that even possible?
...
1
vote
0answers
70 views
Is there a phase shift in a single phase transformer and why?
I was wondering why we consider both sides' voltages and currents with the same phase although they cannot be considered in series.
-2
votes
1answer
145 views
At very high frequency (700 kHz), an AC circuit has a voltage reading 10 times the EMF, why is this?
I've set up an experiment in which I vary the frequency of an electric signal using a waveform generator. The experiment is testing a transformer, but I've encountered a problem on the primary circuit ...
4
votes
2answers
149 views
How to properly snub transient spikes from a transformer and prevent switch mode power supply burn out
I've received a failed switch-mode DC-DC step down converter (part# LTC3631 from Linear). This circuit was driven by a 24VAC transformer which is rectified on the circuit:
simulate this ...
4
votes
1answer
79 views
2 full bridge with 2 secondary winding in series… is it possible?
simulate this circuit – Schematic created using CircuitLab
Is this possible? Think of the center tap transformer as a 2 winding connected in series
2
votes
0answers
117 views
Input and Output terminals of the transformer
I want to use low voltage ac supply for my projects. I have got one from my computer SMPS.
But its winding terminals are making me confuse.At one side,there is 2 terminals(in the picture,it is down ...
0
votes
2answers
386 views
how to use CT to measure current [duplicate]
I have purchased CT but don't know what his terminals means and how to identify primary and secondary coils terminals. I am software engineer but currently learning pic controller. as for I have read ...
0
votes
1answer
337 views
Current Transformer with pic16f877a
I am currently working with a current transformer (CT) to measure the load current of a system. I am connecting the CT with a pic16f877a microcontroller using a basic circuit I found on the internet. ...
1
vote
0answers
182 views
Flyback transformer driven compact fluorescent circuit [closed]
I seem to have run into trouble trying to run a flyback transformer with a CFL circuit.
I connected the high voltage pins of the CFL to the flyback transformers primary input and the other two pins ...
3
votes
2answers
173 views
Centre tapped secondary winding
In the construction of a full wave rectifier, why is there centre tapped secondary winding in the transformer? OR What's the role of centre-tapped transformer in a full wave rectifier?
5
votes
2answers
136 views
Are AC adapters electrically isolated?
are the ac adapters e.g. laptop charger ; are they electrically isolated ( from ground ) because they have a transformer . Im asking this because i read that isolated transformers are 1:1 ratio where ...
-3
votes
2answers
48 views
control transformer
In control transformer ,used in Switchgear i.e. 415V/240V—this transformer is single phase transformer or 2-phase transformer?
As primary is 415 V which is tapped from 2 phase….while secondary is ...
2
votes
2answers
189 views
Can I charge multiple devices from one transformer?
I am getting tired of bringing 3-4 power cables with me every time I travel and am thinking about building a multi-device power charger. In other words, this charger will have one transformer (and one ...
3
votes
2answers
88 views
How can I get 17 VDC from 25 VDC with current may up to 10 A?
I'm new in electronic and electrical circuits, so maybe my question will be naive.
I have an electrical transformer that gets 220VAC as an input and gives 25VAC as an output, and can produce 20amp ...
2
votes
1answer
178 views
advice on a transformer for power-supply
i know this type of question is common and yes i could just buy a known transformer for $10 on ebay or something. either way :)
i am interested in building my own power supply, something variable ...
3
votes
1answer
452 views
PSpice homework Question
I'm having trouble with this question. Can somebody help?
I know the equation for part a) is:
$$P_{\text{max}} = \frac{1}{4} \cdot \frac{\mid{}V\cdot{}t\cdot{}h\mid{}^2}{R_\text{L}}$$
And I'm ...
5
votes
1answer
289 views
Hand winding smps transformer
I would like to hand wind a smps transformer for prototyping work. The specs of the transformer are as follows :
Transformer Parameters
Core Material: EE16, NC-2H or equivalent, gapped for ALG of
...
