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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1answer
24 views

Can you use rectifiers from different transformer sources in pararel?

Consider following circuit: simulate this circuit – Schematic created using CircuitLab It uses two transformers, rectifies their output separately (so that they can't interfere), filters ...
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1answer
47 views

Eddy current in transformer and its minimization

There is a loss in transformer that is known as eddy current loss. It also known as core loss. If we use solid metal instead of laminated layers of iron as core then the eddy current will much ...
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2answers
39 views

Transformer Core Area

I know it from my professor that for a general transformer like this picture if the core was a solid material its area would too big. Thus the core loss increases. To prevent this we use metal ...
6
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5answers
257 views

Can I series windings of separate transformers to increase the voltage rating of the whole?

I need a 1:1 transformer, 25VA 600VAC. I'm not having much luck finding such a thing. It occurs to me that I could take five smaller 1:1 120VAC transformers (like this), series all the primary ...
29
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8answers
5k views

How can “purely” electrical circuits emit sound?

Moving membranes or piezoelectric materials obviously produce sound waves, but how can "purely" electrical circuits such as transformers or DCDC choppers (and others) often have an audible noise? Is ...
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0answers
76 views

Why is my step down transformer getting hot? [closed]

After rewinding with new magnetic wire of same size and turns as before the transformer got heats up within 10 min of powered. Why is it heating?
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1answer
34 views

Center-tap Primary Coil Transformer

What is the function and possible applications of a center-tap primary coil transformer?
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1answer
51 views

Measure 208v single phase with Current Transformer

I have a single phase 208v circuit that I want to measure the amps on. What is the proper way to measure the amps? This is for a connection with 2 hots and a ground wire, no neutral coming from a ...
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1answer
36 views

1:2 stepup transformer suitability

I'm not very knowledgeable when it comes to transformers. I need a 1:2 stepup from approx 30V to 60V peak to peak at 120kHz. I am thinking of using the Murata 782485/35C: Which seems to be ...
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0answers
11 views

Should a heavy duty transformer (used predominantly for LED lights) be on the mains ring or the lighting circuit? [migrated]

I am putting RGB LED strip lights in a room, powered by a fairly heavy duty (30A) 12V transformer. The transformer will also power a Raspberry Pi (volatage will be split to give it 5V)that will be ...
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0answers
18 views

real transformers full load [duplicate]

What is the full load condition of a transformer. Suppose the rating of a real transformer is 15 kVA 2300/230 - V and the secondary current is 0.8 power factor(PF) lagging. Then in reference to the ...
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1answer
24 views

Interpretation of rating of the primary voltage of a real transformer [duplicate]

The rating of a real transformer is 15 kVA , 2300/230-V then can we say that the primary rms is 2300 V or can we say that the secondary rms is 230 V or both. To clarify further, suppose to solve for ...
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1answer
41 views

Interpretation of the rating of a real transformer

The rating of a real transformer is 15 kVA , 2300/230-V then can we say that the primary rms is 2300 V or can we say that the secondary rms is 230 V or both. To clarify further, suppose to solve for ...
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votes
1answer
73 views

How to the calculate the value of capacitor placed in series with transformer to avoid flux walking in a buck converter? [closed]

The dc value of current in primary increases(in -ve direction) as time passes, so I need a capacitor in series with transformer, but don't know what value capacitor should I use. filter capacitor = ...
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votes
2answers
80 views

Difference between DMM and oscilloscope measurements

I have a 220 - 14 V transformer, but when I hook it up to oscilloscope or DMM they show different values. DMM shows 11.8V and oscilloscope shows 17.2. Ok, this is cheap Chinese transformer, so it can ...
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3answers
131 views

What applications require isolated transformers?

I am reading that the principal disadvantage of autotransformers is that unlike ordinary transformers, there is a direct physical connection between the primary and the secondary circuits, so the ...
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2answers
87 views

How can I turn pulsating DC (square wave) from a 555 IC timer into an ac square wave?

I am trying to create build a morse code transmitter. I know that morse code is sent at 500 KHZ so I set my 555 to spit out pulsating DC in a square wave with 9 volt peaks. But I am unsure wether ...
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vote
1answer
72 views

Why would a current transformer act like a high pass filter, how can I estimate the low frequency cutoff?

I am struggling to wrap my head around this. I understand that a transformer is not going to pass DC, and that every current transformer (CT) has some pass band. But what properties drive the high ...
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1answer
75 views

Which transformer faults will lead to power outage?

I have year by year data of number of faults in 330 kV power transformers. Faults are of various kinds and there is no additional information about how many of those faults led to power outage. I am ...
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0answers
36 views

Typical zero sequence data for 80MVA transformer

I need to model a 80MVA transformer 132/33kV built in 1973. There is very little information on this transformer but I need to populate certain values in the model. Where can I find typical zero ...
1
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1answer
80 views

Power calculation of a transformer using only current and resistance

If I use \$P = I^2R \$ for primary and secondary will that tell me the effective power being dissipated? Uf I divide secondary power by primary power and multiply by 100%, would that tell me the ...
2
votes
1answer
84 views

When an isolation transformer is not enough? [closed]

I work for a fairly large church and we have powered line array speakers that do not have attenuators in them. Over time a ground loop occurred from the stage lighting causing a very distracting ...
1
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2answers
54 views

no-load voltage on ac-dc adapter

I recently acquired a toy that uses this transformer: but since I live in a 220V area, I cannot use it directly. I have this generic AC-DC adapter: which in theory is all I need because it has a ...
0
votes
1answer
38 views

Inductances in flyback transformer

I am simulating flyback dc-dc converter in multisim software tool .. I want to know the difference betweem primary inductance and magnetising inductance , also secondary leakage inductance?
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0answers
58 views

Making transformer bobbin

What are the common materials for transformer bobbins? (if possible more specific than thermoplastic materials). I have a transformer that I need to make the bobbin, does anyone have experience ...
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1answer
57 views

Current rating of center-tapped full wave rectifier vs full wave bridge rectifier

I was going through the Art of Electronics (Horowitz & Hill) and in the section on center-tapped full wave rectifiers (pg.47) it says: "The output voltage is half what you get if you use a ...
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2answers
99 views

Power Supply Current is very low

I made a power supply from a diy site, the schematics are above. The site showed the project as 2amps output but I'm not getting even close to that. I'm getting around .14A or less. Does anyone know ...
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4answers
95 views

What is this electronics component?

What is the yellow component shown here? This is off a Outlet USB phone charger.
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1answer
49 views

1:1 isolation transformer fuse on secondary side - an option?

We sometimes use an old self build 1:1 isolation transformer (150VA) in our company to isolate devices under test. It is equipped with a primary 500mA fuse (slow) in series with a on/off switch. ...
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0answers
45 views

Transformers in series for Variable voltage DC power supply

I Would like to build a 15 amp Variable voltage DC power supply using a bridge rectifier, LM723 IC, transistors and transformers (i found a circuit on youtube i would like to try) I have 2 old Cable ...
0
votes
1answer
37 views

Current Transformer Parameters

I have a current transformer with following specification: - LV Current Transformer - Type : RLC-50 - PT : 1 - Ratio : 400/5 A - Class : 1. I want to know the meaning of PT and RLC-50?
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3answers
66 views

transformer 3 taps in the primary

This is a transformer that puts out 13vdc.It has a built in bridge. There are three taps on the primary, which ones connect to a/c? this is going to power a dc motor. Thanks for your help
4
votes
2answers
350 views

How does this mosquito zapper circuit work?

For the purpose of learning, I have tear down a small mosquito zapper racket. I am now trying to understand how the circuit is working (which goal is to produce high voltage). (yellow = ...
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2answers
99 views

Center-tapped Full Wave Bridge Rectifier

I'm designing a high-voltage power supply for a plasma experiment. I have a center-tapped ignition transformer (50:1) that I'm using to step up the voltage from 120VAC to 6kVAC and then using a full ...
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3answers
122 views

With a transformer center tap, why are the two resulting circuits out of phase by 180*?

I'm trying to understand how the power in my home works, and the part I'm having trouble with specifically is why in the step-down service transformer, the resulting out-of-phase 120V "hot" lines are ...
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0answers
44 views

Determine a transformer's windings

I'm trying to find out what the pinout of a transformer is. I found the following diagram in a service manual of a device similar to what i salvaged this transformer from: Now. To test this, I'm ...
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2answers
93 views

Can I use a LED Driver to control a Solenoid?

I have on order an LED driver and I want to use it as a simple 12v DC output to control a Solenoid Valve. The Driver says Constant Current & Constant Voltage. I obviously don't want 1A pumped ...
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0answers
23 views

Combining delta and wye secondaries

I have a situation where I need to aggregate the secondaries of two 3-ph transformers -- a 480Y/208delta and a 208delta/208Y transformer. Will it create any problem?
0
votes
1answer
170 views

Circuit diagram for uninterrupted usage of a 12V 1A device using 12V 7Ah battery with auto charging and full charge cut off

I have a modem which runs at 12V 1A, also I have an UPS battery of 12V 7Ah. I need to design a circuit so that during power outages my modem works from the battery. Also, a circuit to charge the ...
0
votes
2answers
86 views

Can we replace the pulse transformer with some other circuit element in this circuit?

Our research group was trying to simulate and analyse this circuit. But it seems that the pulse transformer is creating the problem in the sense that we cannot find its models in Pspice, microcap or ...
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0answers
25 views

Low Voltage Piezoelectric Driver Design for Loud Output

I need help with designing a low voltage driver for a piezoelectric to output at extremely high volumes -- 120db+. I've seen rape/personal alarms do it with only 2xAA batteries. System Specs: 1) ...
1
vote
1answer
65 views

What Load impedance to use for LC Filter before transformer?

I have an inverter circuit in which I want to filter the output with an LC filter. Lets say the fundamental component that I want is 60Hz. When designing a Low Pass LC filter, I need to use the load ...
0
votes
1answer
67 views

Current transformer saturation

I have a current transformer from this page. I tried to measure the secondary voltage Vs when I apply Vp=230 V and I change the Ip, like this: But at some point the voltage Vs is not changing ...
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votes
3answers
151 views

When should you use a transformer instead of a resistor? [closed]

I feel like this was something that was never taught by my instructor in physics. Is there a certain rule determine when a resistor should be used over a transformer, when stepping down voltage?
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3answers
84 views

finding Q point of thyristor drive circuit.

how to find Q point of the transistor shown in the image. the problem is specifically due to pulse transformer.
1
vote
1answer
73 views

What is an auxillary winding in a flyback transformer?

I am researching about SMPS, specifically AC/DC flyback converters. In the datasheet for the switching controller (Fairchild FSCQ0765), it refers to an auxiliary winding. What is that? All the ...
1
vote
1answer
124 views

Where does 264Vac come from?

Power supplies often accept an input range of 90-264Vac. I am wondering where the 264 comes from. A couple of random examples from power supplies available: 85 - 264 Vac input range (100 - 240 Vac ...
0
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2answers
45 views

Transformer Output Ratio not Exact?

I bought a 115 to 15V toroidal transformer.The turns ratio of this should be (115/15)=7.66 ideally. Now the problem I'm facing is that upon wiring it I'm getting a calculated turns ratio of 6.97, ...
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1answer
87 views

Using a 5KVA step-down toroid transformer as a step-up transformer

I'm somewhat new to electronics, so please pardon the possibly stupid question. I am building a variable speed pottery wheel for the wife for Christmas. I have the wheel assembly and 2HP 1725 RPM ...
0
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1answer
54 views

Small size transformer - Design or Pre-made

I am wondering how to acquire or design a small transformer. In my circuit, I need to add a transformer mainly to power my AVR and a bluetooth module. I would like it to be as small as possible as I ...