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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Stacking M.O.T. to create an E-E core

I just came across this site looking for answers on some questions I have concerning microwave transformers. I am currently going into my third year as an E.E. student and I am trying to design a DC ...
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Choosing RJ45 connector for ENC28J60 (QFN)

I am designing a PoE powered board that uses a ENC28J60 chip to connect to ethernet and power a Raspberry Pi 0. Per the ENC's data sheet, two pulse transformers are required for the ENC. Currently, I ...
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1answer
75 views

What happens when the AC frequency of the primary side of a linear power supply is too high?

When the frequency is too low, the inductance of the primary transformer coil becomes less effective = less efficiency, more wasted current and even lower Hz will lead to a short circuit. Let's say, ...
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S.C. Test on a transformer

S.C. test on a transformer gives us the series winding resistances and leakage reactances referred to the same side of the transformer. My thinking: Winding resistances, RP and RS do not depend on ...
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Power Supply of a VCR [on hold]

My VCR was not working, I wanted to restore it. I don't have enough knowledge about circuit components. Can you tell what it that white round colour thing in the picture?
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Identification of an AC transformer

I have a broken Philips alarm clock FM/AM radio broken, so I stripped some parts out of it. One of it seems like an AC converter, but I cannot find any reference/datasheet about it. Do you have any ...
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Basics of transformer [duplicate]

In a stepup transformer: When we apply 20v to primary winding and the current in primary winding is 5A and the output voltage step up to 40v but current in secondary windings decreases because of law ...
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44 views

Transformer ratings

What physical factors one needs to take into consideration (like maximum core field and saturation) to rate the "voltage rating" of a transformer? Suppose that the voltage rating of a transformer isn'...
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What are the advantages for certain types of transformers? [duplicate]

I work designing medium voltage motor starters. Being an mechanical engineer, I still don't understand the advantages, disadvantages, and when to use certain types of transformers. When is wye-wye ...
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47 views

Connecting two motors in series

I have a 240-volt mains supply and I want to run two identical BLDC motors rated at 120 volts each. Without the need for a transformer with just the help of IGBTs and inverter can I run the motors? ...
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220 volt to 9 volt transformerless [repost] , missing image added [duplicate]

I wanted to turn 220 volts to 9 volts in order to turn on a touch switch , so i used the circuit below but there was a warning in the description which mentioned not to touch the circuit at all , is ...
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4answers
78 views

Detecting if 120v AC wire is live with a 2 or 3 VDC line

For a background, I have 3 DPST bistable (latching flip-flop) relays that I have 120VAC input and 2 outputs. On one side, I have a 120VAC appliance. On the other side I need to find a way to feed it ...
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TRANSFORMER PPROBLEM [closed]

IN A STEPUP TRANSFORMER ---> WHEN WE GIVE 20 V TO PRIMARY WINDING AND LET SAY THE CURRENT IN PRIMARY WINDING IS 5 AMPERE AND THE OUTPUT VOLTAGE STEP UP TO 40V BUT CURRENT IN SECONDARY WINDINGS ...
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Understanding Phase Shift Full Bridge DC-DC Converter

I am studying PSFB DC DC converter. I am a bit confused in understanding the topology. For reference of the functionality I am taking UCC28950 Controller IC's circuit, From TI which have provided in ...
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1answer
46 views

Modelling a transformer [closed]

Is there a model to describe the behaviour of a power transformer? Ideally in regard to several physical quantities. Is there something, even something basic? add-on: I'm not looking for an electric ...
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38 views

Does using only 2 phases (400V) in a 3 phase transformer affect anything?

I just witnessed a 3 phase control transformer in the mcc that steps down 400V to 230V connected only with 2 phases on the 3 400V terminals, and on the other side (secondary) are your live and neutral ...
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28 views

High voltage output from CCFL backlight transformer?

I have an old television inverter board I've been meaning to turn into a power supply for a plate-deflected oscilloscope CRT *. I'm not really an expert on transformers, however, and though I have ...
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1answer
93 views

220v to 9 v transformerless power supply [closed]

I wanted to turn 220 volts to 9 volts in order to turn on a touch switch , so i used the circuit below but there was a warning in the description which mentioned not to touch the circuit at all , is ...
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0answers
13 views

Inverter with UPS transformer

Inverter circuit I am trying to replicate the project on this website: https://electricalfundablog.com/make-simple-inverter-home-circuit-step-by-step-method/ but the recommended transformer is a 9v ...
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22 views

How to reduce noise for arduino capacitive sensing

I have an artistically-painted 5mm-thick wood panel that I want to use as a light switch without alteration to the image. My solution was to (try to) make a specific region on the panel touch-...
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1answer
71 views

Coil Damage Worries [duplicate]

I was trying to make a hv generator from an ignition coil. I bought one from the local mechanics, and put it in a circuit in series with a capacitor and a light dimmer connected to mains 240v. The ...
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1answer
58 views

Transformer testing

I connected an ignition coil to 240v in an attempt to make a Hv generator. The ignition coil was connected I series with a capacitor and light dimmer. When turned on the ignition coil did nothing at ...
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1answer
50 views

High Voltage Planar Transformers

I am designing a high voltage DC/DC converter that is for an aerospace application and therefore I am focusing on reducing the size and weight, so switching at a high frequency possibly integrating ...
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Why are all my motors and transformers failing at this specific location?

At my job there is a vacuum oven. There is a 50 hp, enclosed cooling fan. that circulates N2 gas upon quench, the design of the unit runs 480 volts through a reduction transformer to 230 volts. This ...
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1answer
51 views

On No-Load Current of a Transformer

The no-load current of a transformer consists of two components: The Magnetization Current iM is the current required to produce the flux in the transformer core. The Core-loss Current ih+e ...
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How to solve error from ETAP?

I have crucial circuit and some problem from ETAP I can't solve. Here is the circuit: The problem: When I want to look for minimum short circuit, I get an error that "a loop with incompatible ...
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2answers
57 views

Find instant in which diode starts conducting in transformer full wave rectifier

We have the following circuit V2 = Vs/a; a = 10; Vs = 100sin(wt); w = 200 rad/s; Each of the diodes is modeled by a fixed 0.8 V drop when conducting, and by an open circuit when OFF. Find the ...
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57 views

Transformer's Primary and Secondary Voltages

In general, which is the phase relationship between the primary and secondary voltages of an ideal transformer? Does it depends on the dot convention?
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58 views

Transformer and MOSFET combination not working

I am working to understand the circuit of a vibrating needle used in factories to scratch a mark on a soft surface. Essentially, this circuit drives a MOSFET bridge which then drives a Transformer. ...
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1answer
58 views

Transformer to convert 220V split phase to 220V single phase

I'm a digital guy whose forgotten his "big wire" electrical education. I'm surprisingly unable to find a solid reference for this. I have a (European) 220V 50Hz split phase source (110V + 110V + GND)....
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UCC28C42: TI simulated ,Resistor Heated

I am using an UCC28C42 in my circuit. I need a clarification of some resistor. I am converting 48V to 24V. If my load increases to 4.5A then Resistor is getting heated up.(Circled part) I used ...
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What is the purpose of putting a capacitor on the primary side of a step-down transformer?

I'm looking at this design For a split supply. I get that the thermistors are there to limit the inrush current, but I don't understand the purpose of C9 and how its value was chosen.
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Dot convention meaning

I have two questions about dot convention for the ideal transformer. I have understood how to use them in writing the voltage drops on the coils, but I have some doubts: 1) Which is the physical ...
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3answers
110 views

why is transformer not considered as an amplifier?

I know that in a transformer the power is conserved on both sides, and hence there's no power amplification as such. That's fine! But if I instead want only a voltage amplification, then choosing ...
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72 views

Autotransformer vs Inductive Divider

Which is the advantage of using an autotransformer instead of a simple inductive divider?
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1answer
47 views

Can I Connect Two Totally Different Transformers in Series?

I have 2 totally different toroidal transformers I want to put in series to make 75vac total. I have a decently large toroidal transformer in which I wound many, many turns of 10 gauge wire around. To ...
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1answer
47 views

Can I Use a Transformer to feed a Mains current to a RPI GPIO pin

I have a standard mains (240v) motion detector that activates an outdoors lamp. I want to notify my Raspberry Pi when the lamp is activated. My plan is to use a 240v to 3.3v transformer that I have ...
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3answers
52 views

My push-pull converter uses a flyback transformer with an air gap. How does changing air gap size affect the secondary output voltage?

My push-pull converter circuit uses a flyback transformer with an air gap. If that air gap is changed (increased), the primary inductance is decreased. How should I expect the secondary voltage and ...
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1answer
40 views

Replace speaker to retrieve audio signal (and isolate galvanically)

I'd like to capture sound from a speaker output. The system seems to be running with a small DC current (bias, so voltage across speaker is about 3 V), so the audio AC signal could be (de)coupled from ...
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1answer
50 views

Reading a low voltage signal from a battery connected to a transformer

So currently I am trying to read the current draw from a battery that is being run through a transformer to generate an arc to light a gas burner. I have a roughly 1 ohm piece of wire that I am ...
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1answer
97 views

Difference in current transformers conection for ground fault detection

I have seen that for detecting ground faults on a 3-phase system powered by a secondary wye connected transformer, current transformers (CTs) can be connected in several ways: On the ground ...
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Transformer experiment with iron cores

I have been doing some experiments on changing the medium contained inside a loop of wire from air to iron cores, and seeing the relationship between the potential difference established and the ...
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1answer
63 views

Galvanic Isolation in Automotive Environment

I am using a linear regulator (MIC29302WU) to power a computer mounted inside my car; however, there is significant noise being passed along the ground of the regulator to the main computer. I ...
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6answers
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How does a transformer increase voltage while decreasing the current?

Ohm's law states V=I*R. That means when we increase voltage we must also increase the current(I.) But transformer increases the current while decreasing the voltage or decreasing the current while ...
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2answers
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Arduino + Current Sensor -> Not always working

I am trying to measure power consumption of devices by using an TA12-200 power sensor with a Arduino Uno board. This sensor is using a 800 ohms resistor and a 1:2000 ratio. My measure to get mAh ...
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1answer
49 views

How to Calculate Saturation Current of a Transformer?

Is this Method applicable to calculate? My confusion is mainly regarding with Load current. My knowledge is, that load current is nothing to do with saturation of transformer.
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Positive and negative terminal of a Tesla Coil

I'm trying to build a Tesla coil, I'm using it as a large voltage multiplier, though I can't figure out where is the output positive and negative terminal. thanks!
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1answer
32 views

Understanding 3ph Transformer Specs

I am looking at a Delta-Wye with 480 on primary and 208/120 on the secondary. The transformer in question is Schneider's EX30T3HCUNLP. I came across this drawing in the spec sheet but I am not sure ...
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X Ray Transformer with Full Wave Rectifier Design

I current am in possession of a center tapped X-ray transformer that can supply 80 kV and 10 mA. However, I need this transformer to supply approximately 0 to -37 kV DC at around 8 mA. In order to ...
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Transformer question regarding efficiency

Due to the question being discussed in length on the comment section, I would like to address my question further with a new post linking from the discussion here: Transformers confusion with output ...