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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Will a 110-220v to 12v converter work with a DC 12v 3w LED bulb? [on hold]

I'm planning to create some wall lights using these LED bulbs. Would I be able to just use any 110-220v to 12v converter to power this at home? I live in the US (120v). I was thinking of using this ...
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2answers
61 views

35v reading on 24v transformer

im troubleshooting a 24v ac transformer hooked to two doorbell circuits and on one of them I am getting a 35v reading. What could be causing this? I am reading the voltage using a standard (cheapo) ...
2
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3answers
32 views

How to I calculate the AC amperage draw of a 12 volt 3 amp AC/DC transformer under full 3 amp load?

I want to calculate the 120 volt amperage draw of my 12 volt AC/DC wall adapters, most specifically, one that has a 3 amp rating that is pulling close to 3 amps. Is there a formula for calculating ...
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2answers
55 views

Finding Vout of a Transformer

I am a little confused on how to read the ratios of a transformer Suppose there is a ratio of 1:6, is this read as the following? Number of turns on Primary: Number of turns on Secondary? so suppose ...
3
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3answers
86 views

How to overcome transistor heat in slayer exciter?

I build this circuit and it works but I have two problems. The major problem is that the transistor becomes very hot quickly. I burnt my transistor due to excessive heat. How can I get rid of the very ...
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3answers
74 views

How to correctly wire this transformer for 240V?

I have an old transformer (without any details about brand and model) with dual primary windings. I need to set it up to take 240V, but I am unsure about the correct way to connect the windings in ...
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2answers
45 views

Is an ideal transformer an ideal current source?

I define every circuit element of a primary coil of a transformer that is connected to a voltage source and calculate \$I_1\$ (current of the primary loop). I then connect it to a secondary coil with ...
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1answer
58 views

Ideal transformer output voltage

I know that the output voltage and current of an ideal transformer depends on the number of wounding of the coils. It means that no matter how many resistors I put in a series in my secondary loop, ...
10
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1answer
446 views

What does a black bar across transformer symbol designate?

What does a black bar across a transformer symbol designate? This appears in a power electronics context, and in particular in this case with substituting a DC transformer as an equivalent circuit ...
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2answers
48 views

Calculate primary winding current in transformer under load[Exercise]

I have been trying to get to the answer to this exercise shown in the Solutions' reference page but despite countless attempts couldn't get to it. it reads as follows: ...
-5
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1answer
36 views

why step up transformer is used at the generating station to step up the transmission line voltage?

how it helps by stepping up the generating voltage at the generating station to minimize the losses of a transmission line? when voltage increases current also increases. so it should increase the ...
2
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2answers
42 views

Meaning of infinite self inductance

I am reading about the characteristics of an ideal transformer and it is mentioned that self inductance of each coil is infinite. Could someone help me to understand the physics behind it? When self ...
-1
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1answer
42 views

Safest way to hook a 12V wall plug into a hot/ground source [on hold]

I have no outlets in a room, but have a box that looks like it converts the 120V source into 12V as well as the 120V source. I need to get power to this adapter shown below, but am wondering what's ...
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0answers
50 views

I can not build slayer exciter? [closed]

I built the following circuit on a breadboard but it did not work. Actually, I made small modifications. The resistor was 20 K. I did not use the LED. I tried two coils. The first one has 300 turns ...
0
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1answer
43 views

Transformer output connected to another transformer. Measuring 'Real Power' at input of first transformer

I have a watt meter connected to the primary of one transformer to measure power. The output of this transformer is connected to the input of another transformer. The watt meter is measuring the ...
0
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1answer
42 views

Current Transformer Transformation Ratio Variation

Lately I have been working on Energy Analyzers for Generators. I have a slight problem working with CTs. I ran an experiment with 5 CTs rated at 2.4VA(60/5) of same manufacture with burden resistor ...
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3answers
36 views

Power transformer dual secondaries connection

I am new to electronics and want to build simple circuit. I bought Radio Shack Power Transformer which converts from 120 V to 12 V or 6 V, it says on the back that if I connect two yellow wires it ...
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0answers
40 views

Transformer Winding with multiple primaries

I'm trying to learn about transformers (Mostly for fun) I've been playing around with this calculator after reading some things on it, and it seems like the lower the resistance of the windings, the ...
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1answer
47 views

Is there a limit at the voltage you can apply to a transformer primary?

I have a 9v transformer but all it says is that, there is not info on the primary. The voltage supplied to my house is 120v. So, the transformer will just lower the voltage by a 0.075 factor, ...
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1answer
34 views

Series or Double Input Voltage for Tranformer?

If I'm using 2 identical 120V transformers and I have access to 240V input, is it better to put the two transformers in series to double the voltages on the secondaries, or should I just run a single ...
3
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1answer
74 views

Mathematics Regarding Transformers in Series?

Is there a way to mathematically express transformers in series? I'm curious if I can use the transformer equation to express this, but I'm not sure how to handle it. Would it be as simple as, say, ...
0
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1answer
64 views

Wiring 3 Transformers in Series on 240V?

If I have 3 transformers (120V transformers) in series (on the input side) on a 240V circuit, will the transformers experience a voltage drop? If so, how much and will this affect the secondaries by ...
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1answer
48 views

Can tranformerless inverter topology be used in UPS with a regular battery (12V 7Ah)?

While searching for transformerless inverters in the IEEE site, most of them seem to be about grid connected Photovoltaic inverters. Removing transformers will increase the efficiency at the cost of ...
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1answer
52 views

8 AWG Used for High Amperage Welding?

I've recently seen a homemade AC stick welder that was using 8 AWG wire for the stinger (the electrode holder) and the ground clamp. The voltage and amperage was around 30V at 200A. According to ...
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2answers
27 views

Where should I look for transformer inductance discrepancy?

I'm experimenting with this smallish (~15VA) toroidal line transformer as a "lab" exercise as I'm learning about transformers. Right now it has its original 115V primary winding only; I "unwound" and ...
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3answers
102 views

Variable low voltage AC supply for heating element

(I'm a begineer in electrical stuff). My wife needs a transformer for a leather electric creaser. The transformers sold on the market are ridiculously overpriced (more than 250€). I don't ...
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2answers
56 views

Correctly wire dual primary transformer

I have a dual primary transformer out of an old amp and would like to use it for another project. I can't find a datasheet or a way that explains how to wire it for 220 operation. All the diagrams ...
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1answer
43 views

Calculating a transformer's Short Circuit Current P(sc) [closed]

A 50KVA, 2300/230V, 50Hz transformer has a high voltage winding resistance of 0.65ohm and low voltage resistance of 0.0065ohm and this transformer has been tested to determine, its equivalent circuit, ...
0
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1answer
45 views

Welding Transformers?

I was thinking of making a carry handle for two microwave oven transformers in series, and also so that they can share a common ground without having to split the ground wire. I thought about bolting ...
2
votes
1answer
52 views

Ltspice Transformer Simulation

I am trying to simulate a transformer with a turn ratio of 1:1. The voltage of the primary and secondary are equal but I am getting a different current in the winding (why?). Also I see some DC ...
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3answers
37 views

Direction of flow of current in secondary circuit in AC transformer/rectifier

In this transformer/rectifier if the current in the primary circuit is clockwise what will be the direction of current in the secondary circuit?Why? I'm feeling a bit confused about the direction ...
0
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3answers
92 views

Wiring Transformers in Series With a 240V Plug From a Generator?

How should I wire 2 transformers in series (either primaries or secondaries)(not sure which I should use) using a NEMA L14-30 plug from a generator socket? I'm using 2 Microwave Oven Transformers to ...
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3answers
70 views

Does mutual inductance change individual inductances?

If I have two inductors, with inductances \$L_1\$ and \$L_2\$. I put them really close to each other to make a transformer. Are their individual inductances still \$L_1\$ and \$L_2\$? Or has the ...
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2answers
81 views

convert step down to step up transformer?

I have step down 12-0-12 1Amp transformer input volts 220V and output 12V. As it is step up transformer Np > Ns. I was wondering if I can change it to step up transformer by reversing the input to ...
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2answers
65 views

What is the general operating principle of an AC Electronic Load?

I'm working my way through electromagnetics and in particular power (line) transformers at the moment. I'd like to be able to run tests of various kinds at different AC loads and possibly at different ...
0
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1answer
80 views

What clear plastic stripping is used to wrap a toroidal power transformer?

I'm partially rewinding a toroidal transformer just for the pure thrill of controlling the output voltage. I'm sure I'll get over it, but for the moment that prospect is pretty exciting for some ...
0
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3answers
124 views

Need to build a compact power supply that runs off the 240V socket and provides 12V, 5V and 3.3V for an Arduino Project [closed]

I want to have an as-compact-as-possible (but no limit on size) power brick/supply that takes power from a UK Wall socket and has multiple outputs with different voltages. Need 12V@2A for stepper ...
0
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1answer
33 views

transformer waveform

Can you see the output waveform of this transformer across it's terminals if neither is tied to ground ? I assume it follows the input waveform in shape but if there is no zero reference would it ...
0
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3answers
132 views

Transformer works on PWM at 50Hz?

I have an ardunio setup which is giving me output of 5V and 1A at 50Hz with pulse width modulation. I want to use this as input to the step up transformer and generate output of 60V. considering ...
3
votes
1answer
102 views

Working of miniature Tesla coil?

Can anyone explain the given circuit. I seem to have done it and its perfectly working. But can someone explain the principle/theory and working behind this circuit from when the switch is turned on.. ...
1
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2answers
65 views

What happens if I parallel two somewhat different size transformer primaries?

I have a small toroidal power transformer, perhaps 20VA, about 7cm outside diameter; core cross-sectional area is about \$16 \times 22 mm = 350 mm^2\$. I expect it's a wound silicon steel core. I got ...
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2answers
82 views

Power Supply for Home Automation - SMPS vs Coil Based

I need to design a power supply for my home automation products. I need +12V DC (1A) and +5V DC (500mA) respectively for two different products. One option is to use a circuit with coil based ...
3
votes
4answers
119 views

Help understanding transformer AUX winding

I'm new here and I'm looking for someone to help clarify the AUX winding of a transformer, more specifically in a switched psu. I see schematics where it's being used either as feedback or voltage ...
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2answers
109 views

Ways to voltage shift a wave down to ground

Say I have a wave signal that is always above ground, that is, the signal is positively clamped to the ground. (EDIT: from an input of a helpful user, I now know this should be called "negatively ...
0
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3answers
103 views

generate high voltage using LM555 with a transformer

I'm a French student (please forgive my bad English spelling) who works on a system of portable echograph (you can find the information of the project on the wiki of echopen). Could you help me ...
0
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2answers
59 views

Connecting a Raspberry Pi to a 220V switch

I have a switch that works at 220-230V AC and I'd like to link it to my Raspberry Pi and I want to know what I have to do from an electrical point of view. So my switch, when switched on, places 220V ...
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4answers
134 views

Using the core of a toroidal inductor as the core for a toroidal transformer?

As the title says, I have quite a few toroidal cores that I have gathered over time, and would like to reuse them, do they also work as transformer cores?
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2answers
43 views

(MULTISIM) Feeding sine wave into MOSFET - Getting modified sine wave on drain

I am trying do design a HF power supply/inverter for school. I stumbled across a problem. When i feed a IRF740 a sine wave on the gate, the MOSFET gives a modified sine wave on the drain. Why is ...
0
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1answer
54 views

Amplifier impedance matching with constant voltage speaker systems

I understand that in order not to potentially overload an amplifier one should connect a speaker with an impedance no less than that specified, and I have just recently come to understand that for ...
0
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2answers
44 views

Why do you have to use the nominal voltage of the transformer for the no-load or open-circuit test?

I was wondering why exactly you have to use the nominal voltage of the transformer for the open-circuit or no-load test. Is this also the voltage over the parallel elements, even in a situation where ...