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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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Ignition coil transformer

Urgent! Need answers ASAP! I recently built a HV power supply, as per the link (using a pencil ignition coil). However, I used a capacitor of around 5nf, which meant the supply did not work. The ...
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3answers
1k views

Why do we use a transformer on some heating element projects when the wattage is the same on both sides of the trasformer?

On some projects involving heating elements there's a transformer being used. and the explanation given is "we are using a transformer because need more current" but since the watts on both sides of ...
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1answer
48 views

Designing a step-up transformer [on hold]

I'm designing a new transformer for a project I'm building. I trying to design a new product the primary produces has 2 connections and makes 0.8A. I want to step-up to one coil and need to produce ...
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20 views

Calculating Load Power in a transformer circuit

I've been learning about AC circuits and they seem pretty straight forward, except when it comes to transformers. I have this circuit and I want to figure out the Voltage and Power at R2, and also the ...
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1answer
26 views

Transformer vector group

Given the transformer connection of the primary and secondary winding, in example: Yd11, how do I connect the LV side so I get the correct phase-shift? I understand what clock vector groups represent, ...
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1answer
1k views

What are these obscure components?

I'm having difficulty identifying these components. I salvaged them from a diy power supply enclosure from a garage sale. Each of the black leads in the image attached to female connectors on the face ...
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2answers
88 views

Transformer - I connected 50k resistance which burnt - why? AC

Wall supply gives as much power as a component uses. I'm trying to connect a 800W transformer to produce an arc of electricity. But I can't exceed 10A because home fuse will triger (so every device ...
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18 views

replacing mini stepdown transformer with higher output voltage [closed]

my original transformer details as: 220V 50Hz 10.5V 0.55A I could not find the exact specification to place it in my country, the shop owner recommend another slightly higher voltage transformer 240V ...
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23 views

Unwanted buzzing and reduced volume in a basic speaker set

I have the following device, which basically contains 18 songs. we can play the next song by switching the switch on and off. It also has a volume control. Recently it started to buzz a lot and the ...
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1answer
63 views

Why voltage drop accross a load is higher in case of inverters? [closed]

I have built an inverter circuit, where the circuit works properly for light AC loads e.g. 9 watts, 230V LED bulb etc. and gives an output voltage of 200v, but if I use a 70 watts, 230V exhaust fan as ...
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96 views

How to line a Metal Melter secondary for higher safety

A Metal Melter is a kind of home-made low voltage (less than 40 volts, mine is 3v) welder (small-scale) made from a microwave oven transformer (MOT). I left the primary intact (the thicker wire, which ...
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1answer
103 views

Why Current draw in DC variable power supply is not sizable?

I have done a DC variable power supply, and checked it using multimeter the output voltage ranges from 1.3v to 19v, but the problem is when I added a DC load(small DC motor) it was not working, why? ...
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1answer
37 views

Why does the TUF formula use \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ and not \$V_{rms}=\frac{V_m}{2}\$ for a half wave rectifier

We know that for a half wave rectifier \$V_{rms}=\frac{V_m}{2}\$ and \$I_{rms}=\frac{I_m}{2}\$ But the Transformer utilization factor uses \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ (But uses \$I_{rms}=\frac{...
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31 views

Piezoelectric transducer impedance and phase measurement

I have a circuit comprising of LT1210 current feedback amplifier (supply voltage = +/-15V, gain = 4) and its output is connected to a transformer (RM10 N97) with N=16.6 (150/9) which is further ...
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2answers
41 views

on a network analyzer's measurement what's the meaning of a negative PF?

on a 1 MVA transfomer, process in the place is plastics injection machinery. On the plotted data from an analyzer results in PF jumping from 0.998 to -0.997 (roughly) for all the measurement period ...
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2answers
58 views

Is it safe to use LED transformers with existing 12v halogen bulbs? [closed]

I am in the process of installing two "Tech Lighting" pendant kitchen lamps (each with their own transformer, but on the same dimmer switch). My question is: Can I use MR16 gu5.3 50w 12v halogen ...
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2answers
76 views

How to diagnose transformer failure or expected output

I have a pcb that takes 5v from a main board on pins 3&6 and takes this current through the T1 Transformer (obsolete, no datasheet S1673305) and should output some voltage (service manual does not ...
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2answers
94 views

Is converting high voltage AC into high voltage DC possible? [closed]

I want to convert 2,320 volts AC into 1,000 volts DC. But I’m not sure if this is possible. Or what kind of materials I will need for this. Here are the details of the AC transformer I will use as ...
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1answer
71 views

Why can't certain isolated DC/DC converters operate at over 50% duty cycle?

I am currently studying two switch isolated DC/DC converters, more specifically the Push-Pull, the Half-Bridge and the Full-Bridge DC/DC converters. Several books say that these converters cannot ...
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0answers
30 views

SMPS Flyback transformer selection

I am trying to design a SMPS for a project (I have to make a custom one for integration purpose). This SMPS have universal input (85-265V AC at 50 or 60 Hz) and an output of ideally 53V (but it can ...
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1answer
57 views

Toroids side cover magnetic induction

I plan to put a metal cover to the bare toroid transformer, but the sides would be almost touching (I couldn't find other chassis around). I'm aware the bolt at middle musn't be connected (or shorted ...
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3answers
130 views

If we cannot directly generate DC, why is it said there cannot be any DC transformers?

No matter if permenant magnets, or electromagnetic field is used to generate electricty, there is no way to generate DC directly (except batteries). So, why do we say there cannot be DC transformers? ...
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49 views

Transformer Damage

I recently tried making a HV power supply as per the link (I know it’s very dangerous, lesson learned). I used a pencil type ignition coil in series with a light dimmer and a 5nf capacitor. I ...
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1answer
31 views

Alternative Flyback Transformer

I'm trying to implement the PMP7760 reference design by TI (http://www.ti.com/tool/pmp7760) It uses a flyback transformer namely, the G094215LF which I cannot seem to find anywhere. I found several ...
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Toroids low magnetic field is only for the core?

Here is a thing. When I connect it as 120v (parallel), the magnetic field outside the core is much lesser than when connected as 240v (series). The load of both is same 100v-256v autovolt LG OLED TV (...
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15 views

How to stop the buzzing sound of a transformer? [duplicate]

I have a domestic water purifier that haven't been used for quite some time. My father and I turned it on today and it started emitting a loud buzzing sound. Googling about it, I saw there is a high ...
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1answer
291 views

Is it possible to power a microcontroller via inductance from an AC power line?

I have an AC mains wire powering a pump running at 220V at 5-10A. Is it possible to wind a secondary wire around the outside of the insulation of one of the two "hot" wires (single-phase) to get low-...
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0answers
80 views

1:1 Isolation Transformer voltage output differs

I have this isolation transformer: When input voltage of 240v is used. Actual measured output (with any load) is 250v. Does this commonly occur when they can't really make it 1:1? If you supply ...
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3answers
238 views

In the recent Con-Ed transformer “fire”, what exactly produced the color of the huge blue glow over New York City?

Blue is often linked with technology (e.g. "big blue", glowing pools of water with Cherenkov radiation, aliens in general, Nobel prizes for blue LEDs) as well as traditional things like sparks. In a ...
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2answers
73 views

Connecting the primaries of two 110V transformers in series across 220V

I have 2 identical 110V primary transformers (plug packs but with a small transformer inside) for charging batteries in a pair of US made walkie talkies. Only issue is where I live now is 220V mains. ...
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1answer
39 views

CT measuring circuit with PIC

I am using external CT to measure Current parameter. I am using PIC16F1938 to measure analog . Now here i am looking for circuit and calculation involved to get proper current rating datasheet Min ...
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32 views

DC Variable power supply

I would like some advice on a particular circuit design for a variable DC power supply. Here is some information about what I want to do: I want to do open and short circuit tests on an alternator ...
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1answer
28 views

Does waveform shape affect transformer eddy current loss as frequency changes but peak voltage is fixed?

I'm trying to figure out how eddy currents change with frequency. While learning about this its occurred to me that eddy currents might be impacted differently as frequency changes, if the voltage is ...
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0answers
73 views

Flyback Transformer - Grounding the Ferrite Core

Today I dismantled (I hope this is the correct verb) a flyback transformer. The thing that I've never seen is that one end of one of the windings is "glued" to the ferrite core (Before you ask; yes, ...
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4answers
757 views

Is the link between the earth/chasis terminal and the utility transformer established through a dedicated wire or the soil?

I was following a tutorial on power supply transformers and at the very beginning I have encountered the following illustration: I added the names TG and HG for the LV transformer ground and the ...
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1answer
66 views

Can someone explain this schematic and how to modify it to add PWM LED dimming?

I bought a LED bulb (AC175-265V, 7W, 59mA) to made some experiments with it and inside there's this circuit: Can someone explain me how this circuit works? The small transformer package with a single ...
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1answer
115 views

How would a mains transformer react to unfiltered “Class D” PWM sinewave on its primary?

Somewhat related to this question: How do I apply PWM signal to the primary side of a transformer to get synthesized sine wave at the secondary side? - specifically "Choice 1": However in my case I ...
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4answers
116 views

Too High Voltage Drop across Transformer's Output

I want to get very high current flow thought secondary winding of transformer on my 3 Ohm load. As I apply high voltage of secondary to the load the voltage across it drops dramatically. Only about 2% ...
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1answer
22 views

Why is there difference between the “ideal scenario” and the “ideal simulation” for this isolation transformer model?

The illustration below shows how an isolation transformer is protecting from electrocution by not letting the current to loop through the earth at the secondary side. Neglecting the parasitic ...
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6answers
3k views

Why do high-voltage transformers need oil?

Someone told me that high-voltage transformers need oil because it prevents arcing. However, in terms of dielectric breakdown, isn't air the strongest? I remember from classes in college that as the ...
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1answer
93 views

Connections between 2 separate isolation transformers

If there are 2 isolated transformers 240v and you connect the secondary grounded centertap of one of them to the secondary grounded hot of another. What would happen in such scenerio. How would they ...
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1answer
78 views

What impact does winding tightly versus loosely have on transformer performance?

To make it simple (and actually, directly relevant to what I am working on): what impact does winding tightness have on transformer performance? Lets assume typical laminated EI / EE 60hz transformer, ...
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0answers
74 views

Enhancing the bass response of an audio isolation transformer

Below is a simple buffer circuit using an isolation transformer : The green trace is the output of the transformer and the blue trace is the input signal (20hz to 20Khz sine wave). As you can see the ...
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1answer
32 views

What is the effect of very small AC frequency deviations from the grid on invertors and transformers for normal comsumer objects?

What additional wear or inefficiencies are there from inverting a AC signal to DC from say, 59.99 hertz instead of 60.00 hertz? And is there additional wear on transformers? How do small deviations ...
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1answer
111 views

Ignition coil HV power supply damage?

I recently built a HV power supply, as per the link (using a pencil ignition coil). However, I used a capacitor of around 5nf, which meant the supply did not work. The capacitor reduced the amps too ...
-1
votes
1answer
45 views

Replacement for an AC Transformer

I have a model train set that have an AC transformer. The transformer looks like one of those typical adapters where there is a wire connected to the outlet. Then you have a big black box that weights ...
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1answer
74 views

Power transformer question in vacuum tube circuit

I am having trouble wrapping my brain around this power transformer circuit. I must be missing something very fundamental, so I apologize in advance for that. Can someone explain to me why the center ...
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0answers
26 views

A basic question about an ideal and a non-ideal transformer

An ideal 1:1 transformer rejects common-mode voltages and non-ideal transformer passes it partially to the secondary through due to its winding capacitance. What can be said about the differential-...
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1answer
54 views

Current Transformers (CT's) wired in series for two meters or relays

I'm looking for a wiring diagram for the connection of two energy meters (or an energy meter and protection relay) in series to one set of 3 phase CT's, I've heard it can be done, is it S1 on the 1st ...
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2answers
21 views

Primary current expectation in unloaded toroidal transformer

Background I found a hefty, 7 kg toroidal transformer in visually good condition at a flea market which I am trying to map out. This is part one: I am not sure about what is happening on the primary ...