Questions tagged [transformer]

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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What is the maximum current on the secondary of this toroidal transformer BX1201? [closed]

I recycled a toroidal transformer from a speaker with built-in amplifier, I want to know the maximum current draw in the secondary of the transformer, I can't see any marking indicating the amps ...
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Should I use one thick wire or many thin wires in a step-up high frequency transformer to reduce resistance and impedance?

I am planning to make a step up high frequency (hundreds of kHz) transformer. I want to reduce the resistance and impedance in the secondary. Should I use one thick wire in the secondary, or should I ...
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Can I power my neon sign transformer with a higher frequency?

My neon sign transformer (NST) input says 120 volts 60 hertz. Its output is 15 KV, 30 mA, 60 hertz. I was wondering if I could get a light ballast which I’ve seen drive fly back transformers at 30 ...
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What is the rating of a transformer which connect a generator to the MVgrid?

What is a typical power rating (MVA) of a transformer which connects a synchronous generator to the MV grid? I would think that there is just a safety margin compared to the rating of a generator, for ...
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Transformer ratio of a transformer that connects a generator to a MV grid?

Inside my one-line diagram in which I am studying some properties of the medium voltage grid, I want to connect a generator to the MV busbar to study the hosting capacity. Therefore there is not a ...
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Current transformer wire issues

I would greatly appreciate some advice regarding twisted pair conductors for a current transformer. So, according to the manufacturer, whose equipment I am installing, I need to connect 10 AWG, ...
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Replacing a virtual ground circuit with center tapped transformer

I just bought a cheap headphone amp (those 47 Amp). I aiming to replace the voltage-divider-virtual-ground circuit with a 12v-0v-12v transformer (ofc with rectification). I checked the NE5532's VCC+'s ...
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Why don't simulators work with a self-oscillating voltage booster circuit using a transformer and a transistor?

simulate this circuit – Schematic created using CircuitLab I built this circuit (real not simulated.) With a 3V DC source, the output voltage is about 37V using a 1:14 transformer. I think this ...
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Help designing a safety indicator for a high current transformer

I'm working with a neon sign transformer and want an indicator (preferably a light) on the high/output side to give me a visual cue when there is current coming out of the transformer. I'm not 100% ...
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Looking for a good text book describing active clamp forward converter

Can anyone refer a standard text book for understanding Active-clamp forward converter in detail? I could only find application notes and datasheets on this till now. I have gone through below books- ...
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Modeling three phase load for EV charger

When designing a power system to supply EV charging stations, are the stations modeled as delta loads or wye loads? Slightly off topic but is it standard practice to assume that three phase loads are ...
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A couple of questions about transformers

1: I accidentally supplied 9v to a 4.5v - 0 - 4.5v transformer like this: And it was working for a about a second and then it stopped and isnt working. Have i killed it? 2: Can you use a square wave ...
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AC/DC transformer and isolation

My theoretical knowledge from engineering school is a little bit rusty, and I am not working in this field so I have not been practicing in a long time. But I asked myself a question that I can't ...
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How can the induced voltage be proportional to the frequency?

According to Faraday's Law, in coupled inductors, the magnitude of the induced voltage at the secondary coil is proportional to primary power source's frequency (V2 = w x I1 x M). On the other hand, ...
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2 answers
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How to hook up a transformer to 120V AC?

I'm building a DC power supply and am stepping down my voltage from 120V (from the outlet) to 24V through a transformer. I will be soldering the 3 wires that plug into a North American electrical ...
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Determining the characteristics of an unidentifiable low-frequency transformer

I am in possession of a collection of salvaged transformers. I am curious about this one in particular: I gather from its laminated core that it is intended for use at line frequency. What I assume ...
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What type of power supply is best for short circuit experiments? [closed]

I do a lot of experiments with resistive elements/heating elements, electroplating research work and similarly many other experiments. I'm currently using batteries, batteries work well for some time, ...
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Does skin effect increase the eddy current losses inside magnetic core?

From wikipedia -Ref1 The skin effect also reduces the effective thickness of laminations in power transformers, increasing their losses. From eddy current article in wikipedia-Ref2 "Eddy ...
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cw and ccw transformer secondary

The secondary winding of a transformer consists of two windings in parallel, however they share the same core. They have the same number of turns, one cw the other ccw. Will the corresponding magnetic ...
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Linear Power Supply - Overload Protection Circuit

Summary and Context: Several years ago I bought a linear power supply from Pyramid, model PS-3KX. I would like to understand in detail how the "OVER-LOAD PROTECTION" really works, as said ...
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How does this PNP transistor improve the switching performance of MOSFET?

My guess is PNP transistor might ensure fast turn off by shunting the gate capacitance (ie, when diode is reverse biased and the PNP is on.) Additional questions: Why is the gate current limiting ...
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Homework: impedance equivalence with transformer

I am working on this homework problem and I am wondering if my approach for finding Zeq is correct. I know my matrix is correct, but I feel like I need to do something else to find the correct ...
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AC or DC input to DC output SMPS circuit design

I want to design an SMPS circuit with the following specifications: Input can be either 33-265 VAC or 48-375 VDC Multiple DC outputs (eg. 5VDC, 10VDC etc. ) Output power (40-100W) I am not able to ...
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Sizing a Transformer

I'm trying to spec out a 3-Phase transformer for a project i'm working on, I know that the max load is going to be 40.3kW & I know that the total FLA is 82 Amps operating at 480V @ 60hz, but I do ...
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Transformer humming after replacing halogen bulbs with LEDs

I replaced the IKEA 10W G4 halogen bulbs in my under-cabinet lights with 1.5W G4 disc LEDs and the 120-12V AC transformer started buzzing, but not if I kept one halogen bulb in. I recall reading ...
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Why do 1:1 DC/DC isolation transformers have different inductance values?

I am new to power supply design. I need to design an isolated, unregulated DC/DC power supply, 28VDC, 45W. The purpose of this circuit is just to provide isolation with 1:1 voltage and power. As I was ...
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Safety transformer second fault

I understand the working principles of these types of transformers as there is no connection to earth on the secondary but still can’t get my head around the safety aspect if there was a second Fault ...
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Deriving a graph of current through secondary given graph of voltage across primary

I am a bit confused after a question from my physics textbook. We are currently going through some basics of electromagnetism, one of the topics being the workings of transformers. I figured the ...
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4 answers
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What is the physical meaning to the condition maximum efficiency in transformer?

Mathematically I can see that When Iron Loss = Copper loss there is maximum efficiency, But why is this true? As far as I know Iron losses are completely independent quantities, So I can't understand ...
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3 answers
175 views

Will a 4.5V - 0 - 4.5V transformer work with a 9V battery?

I am concerned as to whether my circuit will work or not before I build it (I am concerned about the battery voltage.) This is what I have but my transformer is 4.5V - 0 - 4.5V. Is there any way I ...
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110 views

Is there a way to make a DC to low voltage AC circuit

All the circuits I see online are like 12v DC -> 220v AC or something along those lines but I'm only looking for something like 9v DC to 9v AC. Is this possible?
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In a forward converter, why do we need a separate controller for secondary side switches?

LT8311 IC is said to be a synchronous controller IC for a forward controller. Why do we need a separate controller at secondary side as the PWM pulses of primary side should dictate the synchronous ...
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How do electronics (like transformers) convert high voltage, low current to low voltage, high current, and vice versa?

I am fairly new to tinkering with electronics/electronic-adjacent ideas and I have been wondering: how do electronics get the desired voltage/current to operate properly? I understand in AC power, ...
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2 answers
83 views

How to protect home from the main connection line short circuit?

I am living in a village and we often face issues with main connection input neutral getting shorted and having good amount of current/voltage. The transformer often gets issues, disrupting supply and ...
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1 answer
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What could be the reason for using line frequency toroidal transformers at the input of a power supply board (with PFC)?

During the teardown of a power supply board, we found a bulky toroidal transformer (similar to image below) at the ac input line (voltage 115V AC). The secondary of transformer is subsequently ...
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Magnetic energy harvesting with a current transformer

I am planning to design a magnetic energy harvesting circuit with a current transformer (CR8349-1500) to charge a super capacitor. Load current rating is 0 to 35 amperes. From the current transformer ...
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LC filter for inverter

I am designing a 1500W inverter. With 24VDC input source and 220VAC 60Hz output voltage. I currently have the topology shown in circuit 1. This results in a square wave at 60Hz. But I need the output ...
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1 answer
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How can I find out what voltage a cd player requires? [closed]

I Have a new CD player which is 120v 60hz 15Watts. It was plugged into UK voltage 240v and the transformer burnt out. I want to change the transformer to allow 240v intake but I don't know how to tell ...
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Cascaded equal transformers

Lets say I have several identical transfomers 1:10 voltage ratio. I connect them in sequence expecting to get 1:100 voltage ratio. This will not work because of impedance missmatch, when first ...
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2 answers
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Toroidal core winding limitations

For traditional laminated EI mains frequency power transformer cores, the core dimensions and core material determine, for a given primary voltage and frequency, a minimum number of primary turns ...
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Need to power an AC Motor from either 120VAC or 220VAC

I am trying to modify a convection oven into a solder re-flow oven. One of my design requirements is it needs to work on both 120VAC and 220VAC (I will need to use it in the USA and over seas). ...
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Which parameter determines the transformer size in a forward converter?

Upon enquiring for a 100W forward converter transformer, the vendor quickly suggested an EFD30 core. Does the size EFD30 represent the size of core as well as window area? As far as I remember from ...
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What is meant by EFD core?

What does EFD stand for in an EFD30 core size? Reference
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Does these dots mean anything?

I'm new to electronics, so my knowledge on symbols is not quite complete yet. So I have an old transformer schematic and I have to get the voltages as accurate as possible. Some voltages are very ...
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2 answers
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Why is the live wire connected to the coil on this transformer?

Mains (230v) is connected to "L" (live) and "N" (neutral) and the voltage regulated device is connected to "1" and "2". "1" (white) is connected to ...
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Duty cycle in flyback transformers

I have a small doubt. If the flyback transformer is designed to vary duty cycle from 5-50% and obtains an output voltage of 5 to 100 V. Here, can we increase the duty cycle beyond 50% (70-80%) as to ...
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How to create a step-down ac transformer without primary coil?

I am currently trying to build a coil gun for a school project in an engineering program and am facing certain resource constraints put on me by the professor. I have looked at many different coil gun ...
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1 answer
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How to simulate a transformer in LTSpice with custom turns ratio and inductivities?

LTSpice calculates the turns ratio of a transformer with SQRT(Lp/Ls). This is however only true if both windings have the same geometry. I have an air-core transformer with an Lp of 10μH, an Ls of ...
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Schematic symbol explanation for transformer with arrow through delta winding

While working on a technical drawing for a station supply transformer in a circuit, I encountered this symbol depicting a 1000/230V Dyn transformer. I am not sure what the arrow crossing the delta ...
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Help in understanding a Capacitive Voltage Transformer

I have been reading up about CVT’s and trying to comprehend some of the parts of the typical circuit which include: A potential divider (C1 & C2). An inductor tapped from the potential divider. A ...
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