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.

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29 views

Multi-winding transformer problem

Hello The above circuit stopped working after a power surge from the mains. In debugging the issue, I started with a voltage check across the two nodes labeled AC INPUT. Their potential ...
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29 views

Making a Microwave transformer

So here is the situation, I am trying to make a simple spot welder from a microwave transformer based of the instruction of this video https://www.youtube.com/watch?v=d5pGN6pqkyY However I tried ...
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1answer
63 views

How to calculate the ratings when a mains-rated transformer is used in a SMPS?

I have a mains-rated transformer that is a leftover part from my previous project. Now since I am experimenting with the idea of SMPS, I am wondering how it would behave when handling the higher ...
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2answers
79 views

Transformers circuit question,where is my mistake?

We have the circuit in the figure I have to find the power in the resistor 4 Ohm Mesh 1 we have : 16=2I1-8I3+V1 Mesh 2 we have V2=4I2 Mesh 3 we have 0=10I3-2I1 5I3=I1 By the circuit we notice ...
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4answers
534 views

Does a current transformer produce a proportional voltage or current?

I bought a current transformer which looks like the one below: Datasheet I wrapped the transformer around my 10A kettle, and measured the values using my multimeter. Measuring AC Voltage, I ...
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36 views

hijack project microtransformer doesn't work well

I am working on a project that need to get energy harvest from smartphone headset jack.I find hijack project has a solution.the energy harvest circuit of it is below: it use coilcraft transformer ...
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0answers
27 views

Led Dinning Table Chandelier construction

I would like to create a brand new chandelier from scratch using G4 1.5w LEDs. I have been searching for the right transformer but I just cannot get started since I need more information about ...
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1answer
38 views

tramsformer input output

I have one machine with transformer from 208 3 phase to 400 3 phase, what will happen if I connect the transformer to 360 V 3 phase as input is it will be okay or not? Because the machine comes from ...
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0answers
38 views

Wiring diagram and phase number of three phase transformer

Does anybody have an idea how to draw vector diagram of primary and secondary of a three phase transformer? For instance, if I need to draw vector diagram for Yzn5 diagram and then also draw the ...
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1answer
152 views

Connecting center-tapped transformer to earth ground; or, why am I being electrocuted?

Silly question here. I've wired up a full-wave rectifier using this dual-secondary transformer. If you want to check my wiring, I connected red-to-orange to "create" the center tap (I assume this is ...
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1answer
41 views

Derive Parameters for Unknown Flyback Transformer

I am designing a 1.7 kV @ 6 mA flyback power supply. The issue I have is that it seems to be extremely difficult to find any type of high voltage flyback transformers for the design. I bought a cheap ...
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5answers
82 views

Connecting two center-tap transformers for isolation transformer

I need to create an isolation transformer so I can float a Device Under Test (DUT). The parts I have to do so are two transformers: 120V primary / 6.3V-0-6.3V secondary @ 3A. I intend to connect ...
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2answers
49 views

Full wave AC Voltmeter Vs True Rms Voltmeter

Does a full-wave rectification AC Voltmeter give the same indication as a true rms voltmeter when you measure a 50 Hz sine wave?what happens if the the sine wave is clipped by an inadequate ...
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1answer
69 views

Why does the volatge drop is huge once a load is connected to a generator?

At no load condition the generated voltage at transformer secondary output is 140 V ac. When a 60W resistive load is connected the voltage drops to 27 V ac. The pmg generator rating is 1 KW 415 V and ...
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1answer
94 views

Is using a transformer at reduced voltage a bad idea?

My Google is failing me. I want to make an isolated AC voltmeter capable of working at 120 or 240 VAC. I've found a suitable 240 volt to 5 volt transformer to use (current capacity doesn't matter - ...
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0answers
30 views

Grounding A Circuit of a Power Tool Battery Charger to Use as Car Battery Charger [duplicate]

I took a charger that matches what I need to charge a car battery. The charger uses a transformer and has 3 connections, as does the battery it's intended for (+/-/T). When I plug the + and - alone ...
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2answers
74 views

Modifying a Simple Transformer Circuit

I have a heavy 14.4V 1.5A heavy battery charger I would like to use to charge my car battery (over time, monitored for heat in a well ventilated area). When I plug the battery to the charger as is, ...
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2answers
79 views

Can I charge a Lead Acid Battery with a Lithium Ion Battery Charger [closed]

Can I use a charger meant for lithium ion batteries (eg a charger for a drill) to charge a lead acid car battery. It charges at 14.4V which is what I'm looking for (and will limit to 2Ah with ...
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2answers
52 views

SMPS transformer orientation with respect to PCB: what's best for EMC?

I have the option of either using a vertical or horizontal bobbin for a flyback SMPS transformer, and I can't conclusively decide which would be best for minimal radiated interference to be picked up ...
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0answers
59 views

Modifying an amp core type transformer

I am attempting to create a 220V AC --> 14.4V 2A transformer to revive a car battery. I took a core type transformer from a music ampifier and want to test it. I don't know how to wire it correctly ...
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2answers
50 views

What will happen if I inject rated output voltage into secondary of a single phase transformer?

I have a mains rated transformer that takes 220V and gives me 12V. Now what if I connect it to a H-bridge drawing power from a 12V car battery like this? simulate this circuit – Schematic ...
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0answers
35 views

High Voltage AC&DC transition on PCB

I'm designing a SMPS and drawing layout onto double-sided PCB. Due to mechanical features of design, both AC and DC current should have transition through vertically attached board. For example, input ...
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4answers
146 views

What will happen to a transformer if rated output voltage is injected to the secondary terminal?

I believe that I have a three phase delta to single phase transformer 1Kva with input 415 v three phase and output 230 Vac single phase. ( Someone help me to identify what kind of transformer is ...
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1answer
83 views

SMPS Design Transformer Core Selection

I'm trying to construct an SMPS power supply with 230VAC at 50 Hz input and 5.6V/2.5A output. Here is the schematic: The design was optimized with EE19 core selected and I am expected to optimize ...
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1answer
41 views

Using a ferroresonant regulating transformer as an isolation transformer

I'm looking to use a (surplus, NOS) Sola (catalog number 22212) ferroresonant voltage regulating transformer (120V primary and secondary) as a low-power isolation transformer (4A) in case I need to ...
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0answers
92 views

DC 5V USB to replace AAA-battery source: down converter

I have a portable lithium battery-powered speaker which takes auxiliary sound input from a single AAA-battery powered pocket radio. The speaker includes a USB port for charging source devices: I ...
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4answers
108 views

Providing house wall switches with 3.3v/5V supply?

It's a bit non-technical, but I'd love to hear the opinions of the pros. I'm trying to figure out what is the best way to connect my home's wall switches (lights, etc.) to 3.3V/5V. The plan is the ...
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2answers
70 views

Reset Winding in Single Switch Forward Converter - How To Dissipate Leakage Inductance?

In a single switched forward converter, the core reset is done by a third winding with opposite dot polarity to the primary and secondary windings. This dissipates the magnetizing inductance but how ...
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1answer
58 views

Inrush Current Limiter for Torodial transformer

Just looking for some quick guidance or good sources. I have a 500VA toroidal transformer I am going to use with my UK mains outlet to step mains voltage down to 25V. I am using a 13A fuse with an ...
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2answers
50 views

Magnetic equivalent circuit with permanent magnets

I am fighting to understand how permanent magnets are inserted in magnetic equivalent circuits. In the image below is an example, at the left, the physical representation of an Iron core with a ...
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2answers
75 views

Transformers in series in the primary end and in parallel in the secondary?

I know the basics of transformers and one thing I have never understood is the specification of primary and secondary voltages. By theory, the 2 parameters of importance is the transformation ratio ...
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1answer
101 views

Workings of a microwave oven magnetron transformer

I took apart an old microwave oven just to see what happens with the circuit inside it. The overall idea is actually pretty simple, but I'm having a hard time figuring out some parts of the circuit. ...
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1answer
70 views

Can varnish affect the performance of the air gap in an SMPS transformer?

In the past I have built several switched-mode supplies using off-the-shelf transformers just using the datasheet properties without having to worry too much about their construction, however I am ...
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1answer
92 views

SMPS Transformer - Secondary voltage rating

I am designing isolated flyback converter with input voltage range 40VDC-110VDC, 5V/6A output. I am struggling with finding appropriate transformer since each and every one I found have lower primary ...
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1answer
61 views

Determine connections of a transformer based on resistance

I have a small transformer I desoldered from a disposable camera that transformed 1.5V to high voltage >90V. It has three leads on one side and two on the other. I have been testing its resistance and ...
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2answers
81 views

Power supply draft advice

I've attained most of the material I need to build my first power supply. The specs are mostly dictated by the parts I have. My intention is a dual isolated variable output power supply that I can ...
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1answer
76 views

Will a Delta to Wye transformer cause a huge loss to Generator output voltage?

I'm planning to convert my three phase supply to a single phase supply. To achieve this I'm planning to use a delta to wye transformer. My major concern would be, will the generator output voltage ...
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2answers
58 views

Parallel transformer outputs

If I fed in ~140 volts at 100kHz to This transformer what is the most power I could get out of it? The data sheet rates it at 36 volts DC 3 amps on one of its three outputs but I am confused by this. ...
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2answers
93 views

Using a transformer with 400 volt rated primary side with a 120 volt line

Is it possible to use a transformer rated for 360 to 400 volts on its primary side on a 120 volt line? Will it still perform adequately? And I would assume the turns ratios still apply? This is the ...
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3answers
201 views

Linear Power Supply Advice

I am new here to StackExchange and new to electronics in general. As my second electronics project (the first being a blinker circuit for a bandolier of LEDs) I am building a regulated linear power ...
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1answer
32 views

Using distribution transformers vs direct connection to primary switch gear

I am trying to learn more about transformers and low voltage electrical distribution. Say you have a medium sized industrial building with a primary switchboard feeding several load centers ...
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3answers
103 views

Transformer size vs. frequency

The size of 60Hz transformers are larger than 50Hz transformers. Transformers designed for operation in the kHz range are even smaller. Why does transformer size decrease with frequency?
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1answer
40 views

How would I properly develop a current rating for this system…?

I have a system that I have recently developed for in house (manufacturing) equipment testing. Transformers rated for 80VA (264V, .303A) are used in series and rectified using a full-wave diode ...
2
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1answer
73 views

Transformer frequency dependence

I have a transformer that I've taken out of scrap. I'm trying to discern it's electrical specifications. In my setup I have a function generator hooked up to the primary winding, and an oscilloscope ...
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0answers
33 views

LV halogen transformer for dimming via PWM control

I am looking for some advice regarding my plans to assemble a circuit to dim a halogen bulb. I am planning to use the principle of switched mode power to control a halogen bulb. I intend to ...
0
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2answers
56 views

Transformer Rating Selection

For selecting a transformer, I stumbled across the following equations for obtaining VA and IAC (citation here). I am dealing with a full wave bridge rectifier with a capacitive load. The wiki ...
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1answer
31 views

Voltage stepping and current reduction

I'm designing a drone to use a relatively new form of propulsion, electrostatic fluid propulsion, which requires extremely large voltages (in the order of 10-100kV) running through a wire to ionize ...
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0answers
23 views

How can i model and simulate transformers in PSCAD?

I am trying to model distribution transformer in PSCAD(Power System Computer Aided Design). I have used the direct block that is in PSCAD, but it has limited input parameter. The input parameters are ...
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28 views

Temperature as a factor in the design of a transformer

How to simulate climate and environmental conditions which is required for the design of a transformer? I am trying to optimize size of winding conductor and size of core used in a transformer. To ...
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26 views

Transformer Efficiency for Galvanic isolation?

I am using a transformer to create a galvanic isolation between the input and the output side. The circuit is low power circuit, so over all, it can not consume more than 3mA. I am driving the ...