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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70 views

LED blinking array using LC-circuit

Basically I want to create a blinking unit to drive my LED's. The LED's are used to be driven at a frequency of ~1.5Hz (that made me choose the values of L and C). So here is my schematic. (I am ...
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4answers
121 views

heat air with nichrome wire

108 rows of grapevines, each row 650 feet long. Suspend a nichrome enameled wire along each row in order to raise the temperature of the air within 18 inches of the wire 6 degrees Fahrenheit. What ...
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0answers
48 views

Sum of energy in a circuit [on hold]

I try to find the error about the sum of energy of my simulation in a simple circuit with 2 inductances, 2 resistors and 2 sources. Inductances L2 and L3 are link together like K=0.9 or 0.5, not 1. At ...
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2answers
57 views

Would driving transformer with MCU's GPIO cause durability issue?

For making isolated power supply, I would like to drive a transformer with two GPIO's of a MCU. The center tab of the primary will be connected to Vcc. And each end of the primary will be toggled ...
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3answers
125 views

Full-bridge rectifier not working as expected

Im trying to create a full bridge rectifier from a step-down voltage source. The circuit is as follows: simulate this circuit – Schematic created using CircuitLab The problem is that I'm ...
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2answers
53 views

Short circuit current through multi-winding transformer

I have a (radial) system with several multi-winding transformers, for instance one 24 MVA 7-winding transformer from 11 kV to 1.92 kV. I want to calculate what the short circuit current will be on ...
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1answer
64 views

How much will be maximum power capacity of a transformer with supper conducting wire

If I wind a specific transformer with superconducting wire and take away temperature from the core by means of some way, how much power can I take from transformer? I should mention max power capacity ...
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1answer
30 views

Multi transformer to have high voltage

I'm trying to generate high voltage from 5 volt battery source. Currently, i have some normal transformer from my old devices, i think it can gain from 5 volt to 220v. I just wonder that if i connect ...
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1answer
29 views

Modeling transformer in Ltspice

I am trying to model a transformer of 1:100 ration in Ltspice, here is the picture of it The above circuit is stepping up the input voltage by 100 times but I see something strange which is when I ...
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4answers
183 views

What makes the transformer in a SMPS smaller?

I'm reading up on how SMPS's work, and all the videos says that after the high-volrage chopping stage, a smaller transformer can now be used, because of this high frequency. My question is, how does ...
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1answer
27 views

Question about ideal transformer

Let's say that an ideal transformer has a rating of 500/125 V, 10 kVA. The source voltage applied to the primary winding is 525 V (rms). The load that is connected to the secondary winding consumes ...
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2answers
28 views

Transformers, input voltage range

I have a transformer based AC fan controller (rated for 230V input) with five output steps ( 230V(5) - 200V(4) - 160V(3) - 140V(2) - 125V(1) ). I would like to have more fine grained steps, and am ...
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1answer
51 views

Limit for inductances

In the circuit below : It is possible in physics to have : L1 = 1 H L2 = 2H L3 = 1 H and couple inductances like that: K1 LL1 LL2 1.414 K2 LL2 LL3 1.414 I think I must respect K < ...
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0answers
65 views

Why doesn't this UPS use a high-frequency SMPS inverter?

So I've bought a 350VA off-the-shelf UPS so I can continue learning about how things are done - you know, things they don't teach in the classroom. I get the thing open and I discover what appears to ...
1
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1answer
53 views

What type of transformer is this?

I have a design project for my electrical engineering class where I'm designing a signal tracer akin to Tripplett's Fox and Hound series. For a reference, I tested the output of a commercial tone ...
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1answer
60 views

How does the principle of conservation of energy for a phase-shifter transformer apply?

Since the phase shifter transformer is used for regulating the real power in the transmission line by means of changing the angle it leads to the fact that the real power at the secondary side ...
2
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3answers
334 views

Current and voltage in a transformer

I would like to find currents and voltages at R1 and R2 resistors. I put sinus voltage at left , 12V for example with frequency at 50Hz. Each coil has the same number of turns N. Irons circuit have ...
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3answers
1k views

Why don't AC transformers burn up

I'm marginally familiar with the way that an AC transformer works. After viewing this question: Why don't all motors burn up instantly? It got me thinking about the same thing with AC ...
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1answer
44 views

Does low frequency PWM create reactive power in a transformer?

I got a 350VA transformer (230V~/24V~) which is directly connected to a heating unit at it's 24 V ends. The 230V end of the transformer are connected to 230 V~ mains over a solid state relay (SSR). ...
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0answers
48 views

How to get better output out of flyback driver?

simulate this circuit – Schematic created using CircuitLab I used this circuit to power my flyback... I used an MJE3055T Power NPN and 10kOhm pot. The flyback is FKD15A001. I used the ...
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0answers
62 views

High current SMPS transformer

I would like to have some tips concerning DIY winding of SMPS transformers. Let's consider the following example (for reference only): Input: rectified 230V AC (mean value: 310V DC on the DC-link ...
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1answer
57 views

In the transformer equivalent circuit,why the primary and secondary windings are not coupled with magnetizing inductance?

simulate this circuit – Schematic created using CircuitLab The attached diagram is the equivalent circuit of a practical transformer. Why is the coupling shown only between primary ...
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1answer
83 views

Current Transformer giving a reading when not clamped around a wire

A split core current transformers is currently clamped around a live wire. One end of the transformer's output wires are connected to the analog pin of an Arduino and the other end has a 2.5V bias ...
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1answer
52 views

Will a Transformer work from a DC inverter's output? [closed]

If so, is it ever more efficient to use an inverter into a transformer to dial down DC Voltage?
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0answers
33 views

Are there standard-sized packaging for power transformer?

I am looking to add transformer to Eagle CAD design. It looks like transformers come in all sizes based on manufacturer. Are there standard-sized packaging for power transformer? Do I have to resort ...
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1answer
107 views

Small AC Transformer

Came across these small Zwave controllers here .These are small enough to fit inside the electrical switch housing in the wall. Just wondering how is this device so small as the AC->DC transformer is ...
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2answers
65 views

Current spikes in simple transformer?

I'm using 220v -> 48v 830 W transformer directly connected to the 220v grid and used to operate my PCB drill. The issue with transformer is that it's making irregular (with 0.1-2 min interval) sudden ...
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2answers
225 views

It is it possible to safely use a 110V variac (variable transformer) at 230V?

I've come across a variable transformer/variac which is designed to be used with 110V input. Our line supply here is 230V. If I was careful not to exceed the VA rating of the transformer (920VA) ...
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2answers
132 views

Should I use step-up or step-down transformer?

I am designing a 21" tablet using a development board, the development board takes 5V DC whereas the display takes 12V DC. The display will take around 800mA and the development board around 500mA. I ...
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0answers
35 views

What should I use: Hall effect sensor or current transformer?

I have to design a generalised kit for online condition monitoring of induction motor (1Hp, 3hp and 5hp) and monitor voltage, current and temperature. I was thinking to use a Hall effect sensor/clamp ...
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0answers
22 views

Max primary current for a transformer with a variable coupling coefficent k

I'm trying to model a variable k transformer in Pspice, but I'm doing some rough math on paper first. The problem says to do a sweep for k, find the max current in the primary, and then plot a few ...
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1answer
50 views

Radio antenna isolating transformer

I need to isolate galvanically my antenna from my RF transceiver. For this I have been recommended a transformer, I select a 1:1 transformer operating in high frequency range. Is it enough to wire it ...
2
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1answer
134 views

What happens to a transformer if the supply side is shorted?

Suppose I have an industrial plant, where a switchboard is fed through a transformer. The switchboard have only "passive" loads, i.e. they don't contribute with short circuit currents. If there is a ...
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1answer
52 views

Middle-Tapped Transformer Full-Wave Rectifier Vs. Full-Wave Bridge Rectifier

In terms of output voltage, which one of these would be best? Coming into this, I would have to say the center-tapped transformer full-wave rectifier would allow the most accurate output voltage ...
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2answers
132 views

Understanding transformer ratings

I have a transformer that has the following specifications: Primary: 220V Secondary: 12+12V Rating: 5A Does this mean the transformer has two 2.5A windings? Or is each winding capable of ...
2
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2answers
198 views

Transformer coils in series, switching for 12/24V. EMF killing my circuit?

I'm making a little linear PSU for my lab. Based on the good ol' LM338K. I fried one last night and I'm still trying to figure out why. I think it might be EMF from my transformer. I have a ...
7
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1answer
209 views

Help me modernize this audio circuit

When I was a kid, I built this circuit. You hook up a small capacitor to the test leads or maybe a couple in parallel and the speaker will output a different pitch based on the test capacitance. I ...
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2answers
77 views

Using a pair of 220v-110v transformers together

I have two transformers (220v to 110v) which has a nominal power of 300VA. I want more than that for a specific application. Can I use both together to supply more current like this (?): Any chance ...
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0answers
46 views

Old variable speed AC motor wiring

As a disclaimer, I have a little electronics knowledge, but I'm no expert. I've been given an old 1940's Hunter fan and I'm working on fixing it up. I took the base apart and wiring is pretty bad - ...
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2answers
126 views

Why not multiply Electrical power with stepup transformers?

I saw youtube video showing a stepup transformer(from microwave) double the electricity than input. 12v input and 120v output. why not its possible if connect many stepup transformers(1st transformer ...
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2answers
86 views

Modelling large air gap transformer

I am trying to model a wireless energy transmitter as a transformer equivalent circuit with a large air gap. Because of the large air gap I’m assuming that for a realistic model fringing fluxes would ...
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3answers
152 views

What is the purpose of this spiral wire on top of the transformer body?

A follow-up to What are the ratings of vintage Selenium Rectifier B20/16-2,4? The photograph linked shows, in the red-box, a spiral wire on the transformer body. What is the purpose of this? p.s. ...
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0answers
70 views

AC 3 Pin Transformer vs 2 Pin Transformer

I am in the middle of learning, and planning to build my own high power 110V AC to 5V DC power supply capable of handling around 15 to 20 amps of power (custom power supply for ~10 Raspberry Pis). I ...
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0answers
28 views

How to determine correct voltage input on a multivoltage power-transformer?

I have an old tube radio that has multiple mains selector - 240V; 220V; 127V; 110V. The back-plate where the description how to set the selector correctly has gone missing. There are no markings ...
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3answers
99 views

Efficiency of Halogen lamp Transformer when used with LED lamps

First off: I live in a part of the world where our grid runs at 230V, 50Hz. In case that matters. I bought this house with numerous 12V 50W Halogen downlights, each with their own step-down ...
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0answers
56 views

Using low-voltage halogen transformer for LED?

During a recent kitchen renovation, the electrician installed LED under-counter "pucks" and drove them with a 120VAC-to 12V, 40 kHz transformer labelled "low voltage halogen supply." I'm fully aware ...
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5answers
233 views

Transformers vs. voltage regulators

I'll start by saying that I'm self-taught in electronics, and tend to ask a lot of questions because I don't know NOT to ask them. This is one of those questions. Consider: I have 120VAC and need ...
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2answers
201 views

How to convert 6V AC to 5V DC

I'm looking to convert 6v AC (.5A) to 5v DC for use in charging a phone via USB. idealy a relatively inexpensive pre existing solution would be perfect, but I've been unable to find anything like that ...
4
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2answers
94 views

What are the effective power limitations of the flyback converter topology, and why?

Looking at several different isolated converter topologies, flyback looks like it's the simplest at first glance. There's only one switch, so there's only one driver, which (all other things being ...
4
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3answers
311 views

What is the difference between a transformer and a coupled inductor?

Transformers and coupled inductors seem very similar. Is there a difference in construction? Or only in use? This question asks something similar, but the answers don't address my question: Coupled ...