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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8 views

Problems in 3 phase transformer connection in wye-wye [on hold]

How do the problems (third harmonics, unbalanced load) in wye-wye connection of a 3-phase transformer occur?
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1answer
49 views

Dual power supply: two secondaries or series regulators?

I am going to create a simple dual voltage power supply for powering logic (5V) and some stepper motors (12V). What would be a better solution: Would it be to use a transformer with two secondaries ...
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3answers
55 views

Transformer in flyback DC-DC converter

How can a DC supply be given to the transformer primary in a flyback DC to DC converter? In a flyback converter there is a transformer and DC supply is given to it. How?
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1answer
73 views

What are the bare minimum parts needed to operate a magnetron?

I recently took apart a microwave, and I managed to get a magnetron out of it, as well as a transformer that appears to be the power source for the magnetron, but looks a little small for the ...
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1answer
38 views

Is RF Transformer Impedance Significantly Affected by Wire Size?

I'm building a Softrock Ensemble III HF Receiver. The online instructions are pretty good, but have a few remnants from an earlier version that no longer apply. So, despite the discussion about the ...
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4answers
115 views

Impedance matching for amplifier output

I needed some basic advice about impedance matching. I have an RF amplifier with 50 ohm output impedance, capable of generating 400W output power at 500kHz. I am trying to deliver this to a 12 ohm ...
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2answers
63 views

How to purchase the right transformer for an electronic device [closed]

I just purchased an IP telephone that comes with no power transformer. I think the manufacturer assumes that buyers will be using power over ethernet. On the back of the phone where the power jack ...
2
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3answers
195 views

Is my PSU design safe, what should I change?

Normally I would just go and breadboard the design out, but since this is using mains power, I would rather ask experienced people first. I want to build a desktop 170V DC power supply to fiddle ...
2
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1answer
260 views

Is my power supply calculation correct?

So I am trying to get into higher voltage projects, namely I got a bunch of nixie tubes very cheap. I was thinking of making my supply by connecting a 230v -> 9v transformer back to back with a 230v ...
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2answers
40 views

Transformer primary and secondary voltage phase shift

If we apply a voltage at the primary terminals of a transformer then for this we can get a voltage at the secondary. But they have 180 degree phase difference. What is the reason behind this?? I ...
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1answer
52 views

Why is a variable frequency drive (VFD) always powered from a phase shift transformer?

I have seen VFD of rating (350kW and above) are generally powered from a phase shift transformer. Even when the load is considerably high why cant we use an ordinary transformer instead of phase shift ...
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1answer
26 views

Selecting 2 pole branch circuit protection

I am trying to select a 2 pole circuit protector (UL489 approved), to protect a 575V transformer. I am however unable to find any 2 pole CB that go above a 480Vac voltage rating. Is there anything I'm ...
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2answers
36 views

Passing control voltages to multiple isolated power supply channels

I'm designing a programmable bench power supply (PS) that has multiple isolated channels (each powered by a separate transformer winding). I like the idea of isolated channels so that multiple ...
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2answers
56 views

Can you use rectifiers from different transformer sources in parallel?

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
51 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
49 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
286 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 ...
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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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1answer
42 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
62 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
43 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
20 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
31 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
48 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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1answer
81 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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2answers
87 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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4answers
149 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
98 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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1answer
94 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 ...
2
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1answer
88 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
46 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 ...
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1answer
98 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
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1answer
90 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 ...
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2answers
64 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 ...
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1answer
40 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
69 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
90 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
101 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
59 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
50 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 ...
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1answer
38 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
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2answers
422 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 = ...
0
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2answers
118 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
138 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 ...
0
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0answers
49 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
95 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?
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1answer
258 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 ...