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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Transformer in microwave board acting weird [closed]
I am trying to fix this microwave board. I checked the transformer leads and I can see the resistance between the input leads is 1.6 kΩ (I am not sure its the input since this issue is pretty weird) ...
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DIY RF Noise Bridge: Anyone use an SMD RF transformer with success?
I am building an RF noise bridge (DC-100MHz (200-400, even better) to replace one that failed in my Palomar Engineers antenna tuner. I am using SMD components and have completed the implementation of ...
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Voltage Transformer Troubleshooting
I have an LVAC Switchboard with 3x Incomers, all fitted with a 250A 4P MCCB. On the incoming side of each incomer, I wire to a 25VA wye-wye voltage transformer 400/110VAC. The secondary side of the ...
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If a DC motor accepts a higher and a lower voltage (for 2-speed modes), which speed will have more current drawn?
The load is a DC massage chair motor and nothing else changes when stepping down to the lower voltage (meaning no gear or other mechanical changes that would impact load). Will there be more or less ...
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Can I replace a 3-lead single coil transformer with an isolated type and tie p and s neutrals
The circuit I need to power has a 120vac side, powered straight from mains, and a 48vac side, previously provided by a 3-lead autotransformer. These two mutually exclusive paths to the rectifier ...
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Driving a transformer with an AC to AC converter
I have a variable inductor which operates at a 60Hz frequency this goes to a control board that takes this variable voltage and applies it to a high voltage transformer. I want to control the output ...
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Resistor purpose in following circuit
I would like to understand Why is there a small 20 ohm resistor next to the transformer? What is its purpose?
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Why Are Node Voltages Not Equal in Transformer Circuit with k=1 in LTSpice?
In the first transformer circuit, where the coupling coefficient k = 1, the effective circuit seen by the first source (V1) of the second circuit with source V2 is ...
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PCB routing: how to connect the ground?
I want to create a PCB schematic of a very basic AC/DC converter and I'm a total newbie.
What's the best way to connect ground pins? Transformer is through-hole. Do I have to pour in a second layer ...
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What are maximum turns ratios of transformer? Do we really need a turns ratio meter with turns ratio range of 1-50,000?
I'm studying transformer turns ratio and suitable turns ratio measurers. I found that some turns ratio meters have range of 0.8 - 10,000 and even up to 0.8-50,000. My question is how the maximum turns ...
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Flyback transformer design
My question is almost similar to the question Google.
The flyback transformer is actually a coupled inductor. So it must be designed like an inductor.
After obtaining the required inductance, it is ...
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How to make a electronic circuit work with Delta and Star Configurations
I have developed a circuit board that measures the power consumption of a three-phase power supply with a star (wye) configuration (the circuit consumes less than 5W). My system is currently powered ...
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How does an autotransformer change voltage if primary and secondary share the same wire?
I just learned what an autotransformer does, but I'm not understanding how it works.
So, a typical transformer has a primary wire wound around a magnetic core with an AC source, which creates an ...
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Impedance matching between two differential ports
I am attempting to match a 50 ohm differential source impedance with a 150 ohm differential load over a wide band (1-15 Mhz) for a receive path.
I am trying to figure out if I can use only a single ...
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How does a voltage transformer work under load?
I understand that under no-load conditions, a transformer behaves like a typical inductance coil with an impedance \$Z = j \omega L\$, essentially carrying only the magnetizing current \$I_\mu\$, ...
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Is Using Resistors in Doubly Tuned Transformer Impedance Matching Circuits for Low-Frequency High-Power Transducers Advisable Despite Power Loss?
I am designing an impedance matching circuit for a transducer with frequency-dependent reactance, adopting a doubly tuned transformer structure. I have heard that impedance matching circuits are ...
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Understanding primary current in half-bridge push-pull converter
I am currently investigating a half-bridge push-pull converter and I am struggling with understanding what I see on the oscilloscope. (And why it keeps blowing up).
So for the circuit, its as basic as ...
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Problem with data given for transformer design
I'm using STelectronics design tool for making a SMPS, you can check this link to design yours STelectronics Designer.
The problem is that with the given data of the transformer is not clear for me, I'...
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Adding an output to a SMPS transformer
I'm working on this SMPS circuit (recommended by STMicroelectronics). If you have any suggestions for improvement feel free to comment that.
As you can see, the output has 12.05V, but I want to add ...
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Could you stop current flow with an open circuit transformer?
In a transformer circuit we know that if the secondary side is an open circuit then there will be no current on that side. Therefore, no current can flow on the primary side either because of the ...
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Can a pulse transformer be used for single phase 120V AC isolation?
I am looking to build a ~170V DC power supply by using a full bridge rectifier on wall outlet 120V AC. After some googling I've come to learn I really need the output to be isolated as I'll be ...
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Are AC-DC SMPS power supplies safe for swimming pool lighting?
I have seen some vendors selling 24 VAC transformers to power up swimming pool lights that are submerged in the water. These lights also work with DC but I think transformers are being considered ...
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Determine inductive elements in transformer model
A model of a single phase, \$500 \text{V} / 6 \text{V} \$ two winding transformer, with an ideal transformer in the middle is seen below
simulate this circuit – Schematic created using ...
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Measure Common Mode Choke Impedance on VNA
I am seeking clarity on measuring a common mode impedance and attenuation on an HF 1:1 common mode choke. The chokes are broadband, typically 2 to 30 MHz, wound on toroid cores with type 31 and 43 ...
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Transformer Voltage Question
If I have an AC source outputting, theoretically, 10 volts AC at 1 kHz, then if I connected this ac source to a transformer with a ratio of 1:10 for primary coils to secondary coils, then connected ...
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Transformer power mismatch in Falstad Circuit Simulator, bug or true to life?
To understand how transformers function better, I created a circuit in Falstad Circuit Simulator. As you can see since the transformer has equal amount of coil windings in both sides, the current and ...
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How do those 2 transformers work together to drive ultrasonic cleaner's piezo?
For a couple days I try to understand how the following ultrasonic driver circuit works. Possibly it drives a 40 kHz piezo. I reverse engineered and drew the circuit. There are lots of things that I ...
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Why does transformer insulation resistance decrease when filled with insulating oil?
This question was asked by someone: "It turns out that this is normal, so what is the reason for this?"
After repair of a transformer, it was shipped overseas without insulating oil. Prior ...
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CRT impedance-matching-transformer design questions
UPDATE:
I'm going to be honest, I am in way over my head here. I don't have the necessary math skills and analog design experience to make this elegant. I just want this to work at all. If anyone can ...
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Current transformer core sizing and selection
Thinking I know the most about inductors and transformers, again I am confused about how to select and size a transformer core. I needed to make a quick 30A current transformer. I tried to calculate ...
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Are microwave oven transformers usually bigger if designed for 230V vs 120V?
Consider a 1kW microwave oven designed with versions for both Europe and USA. The 50 Hz of Europe should theoretically force a slightly bigger, and more expensive, transformer, but what about the ...
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Transformer dot convention
If both input and output voltages are in phase, both dots will be shown up.
If the voltages are out of phase, the second dot will be shown down.
But how can the voltages be exactly in phase or exactly ...
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Ground to Phase potential in a ungrounded tri-phase network
I would like to know the possible potential difference between a phase and the earth of an ungrounded three-phase network (intermediate network of figure below).
I can't find out if there's a ...
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What happens if you have 208 V 115 A transformer on a 150 A breaker and you put it on a 100 A breaker? Breaker to transformer to machine [closed]
What happens if put a 115 A transformer on a 100 A breaker?
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Interpretation of power in WPT systems - given a requirement of power, find an adequate value for the inductance
I need to design the coils for a WPT system. I was given something like a note where the topology was drawn, and then with all the maths and reasoning the main formulas for the power of the circuit. ...
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Flyback transformer inductance value variation
I have using core EE (E30/15/7-3C90-E100). In that I have winded 18turns - 2nd method (refer attachment) where inductance value observed 50uH higher than calculated (18x18x100x10^(-9)x1.05 = 34.02uH). ...
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Transformer calculations for a voltage-fed push-pull converter
I am designing my first voltage-fed push-pull converter, and I got stuck during the transformer sizing process. I am not exactly sure how to proceed. I have determined the primary and secondary peak ...
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Why does transformer current change with different inductance?
See the LT spice simulation screenshots below. The circuits in both simulations are exactly the same, except for the inductor values used in the transformer. The voltage source is generating a 1 MHz ...
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Increased noise at Transformer Secondary with no input signal
created this prototype (on a PCB):
Input signal (V3) frequency range is 0-4.5kHz, 0-20Vpp.
With no input signal connected (no V3), I see this noise at OUT-A:
Worse, noise increase at 1:1 transformer ...
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PoE+ output voltage
I would like to measure the output voltage from a PoE+ injector.
This is the schematic provided for the PoE+ injector that I am testing.
Can someone help me out with that?
Here is a link to the ...
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Transformer Cores Datasheets - Core Loss Information
Transformer core datasheets generally have Core loss - Pv (kW/m3) versus Flux Density - B (mT) graph but some doesn't, instead it is given in a table as shown in the picture below for one of the EE ...
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Impedance matching using Balun
community, your help and guidance is needed!
I want to design an impedance matching circuit in Altium Designer using the following diagram.
Here are the details of my design:
The left side is ...
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Planar transformer core power handling
I have come to a point where I’m required to design a planar transformer, nevertheless that’s honestly the first time I’m designing any magnetics and I have thus very little experience.
The output ...
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How to determine the power rating of transformer
How can I determine the power rating of a 3-phase transformer 33/0.415 from a construction point of view?
I understand that kVA = V x I x 1.73 / 1000.
But, if I may ask how can I be able to determine ...
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Can I use a forward transformer in a flyback converter circuit?
I'm working on a power supply project and was wondering if it's possible to use a transformer designed for a forward converter in a flyback converter circuit.
I understand that these two topologies ...
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AC vs DC supply for ~50ft, ~500mW load from 110VAC
I am looking for the most efficient way to power an ESP8266 micro controller via ~50ft AWG18 low voltage wiring from 110VAC. For the ESP itself I assume a pessimistic 100mA at 3.3V but the board has a ...
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Weight of an AC/DC transformer and wattage [closed]
You know those basic AC/DC adapter that come with every small appliance? What's the real map of the current technology/capacity? Averages, ballparks, IME allowed.
For example, I have plenty of 110V AC ...
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Would this configuration of microwave oven transformers work to make a simple arc welder?
I know arc welders typically require 15-30 volts and 100-200 amperes to work.
I have two microwave transformers in which I have removed the secondary winding and wound 15 turns each of heavier wire ...
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What is the risk when floating oscilloscope and DUT?
As far as I know the best practice for doing high voltage measurements with an oscilloscope is either using HV differential probes or connecting the DUT to an isolation transformer while having the ...
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LLC halfbridge design startup fault
I have an LLC halfbridge design, using TI's UCC256404 chip, and I'm having a fault declared during initial startup. My primary side aux rail gets bumped up beyond the regulation point, which causes ...
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