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.

learn more… | top users | synonyms

0
votes
1answer
31 views

Initial permeability of toroids in ATX power supply?

I'm interested in re-using output side or possibly the line filter toroids from a junk ATX switching supply. All turns are removed, just the core. I think these are powdered iron cores and any guess ...
0
votes
1answer
26 views

step down transformer 20-0-20

I want to make transformer which can convert 220 volt ac to 20-0-20 volt Ac(Step Down) 6 Ampere for audio Amplifier. Now I have a question that For 6 Amp Calculation I should consider 3-0-3 Ampere for ...
1
vote
1answer
19 views

Making planar transformers in Altium

Does anyone know of a decent (repeatable) way of making planar transformers/planar inductors in Altium? And if so, how was the experience? Drawing out the tracks and checking trace/space clearance ...
-1
votes
0answers
25 views

110v rated Receiver to 220v [on hold]

I just bought a Yamaha Hifi receiver in the States and I'm bringing it to my country, where the mains voltage is 220AC. USA based yamaha branded receiver are not multiple voltage cappable, so I have a ...
1
vote
1answer
20 views

Intermittent Pulses in Anti-phase Step Generator

I've recently been studying some old circuits, in particular some of the Heathkit circuits and I'm currently looking at this one: IT-1121 Curve Tracer. Here's a snippet of the step generator which ...
1
vote
2answers
47 views

Impedance matching for piezo element

I am trying to boost audio signal from around 3V to around 60V for a piezo element with a component as small as possible. I found audio transformer MET-23 that reflects 1.6 kOhm impedance on primary ...
0
votes
2answers
47 views

Tesla coil charging the battery with AC?

For Tesla coil, eventually the capacitor voltage becomes so high that the air in the spark gap is unable to hold-off the high electric field and breakdown occurs. But usually from what I know DC ...
0
votes
1answer
37 views

What is the transfer function of a transformer?

Consider transformer as a black box. We give arbitrary input voltage \$x(t)\$, what is the output \$y(t)\$? Naive thoughts: if \$x(t)\$ is a sin-wave, \$y(t)\$ is a sin wave also, with the same ...
0
votes
2answers
58 views

Power Supply Circuit ±9V from a 6V centre tap transformer

At work, there's a power supply which is used on one of our products. The guy who originally made the board has since left and none of the senior electronics guys could give me a good answer. Here's ...
1
vote
1answer
65 views

Designing a Smaller 2000W Transformer PCB to Run 220V Heating Element on 110V

I'm trying to design a step up transformer that can run my 220V heating element on 110V outlet. I've looked for such transformers through retail, but most of them are bulky and heavy. Is there a way ...
-1
votes
1answer
64 views

how i can get 5V AC output from 230V AC [closed]

how can'i get 5 V AC output 230 V AC: input? for a measurement unit bases on DSP?
0
votes
3answers
63 views

2 amp transformer alternatives [closed]

Beginner here, please bear with me. I'm following instructions to modify a popcorn popper for coffee roasting: http://popperyii.blogspot.com/ It looks like it requires a 25.2 VCT 2A transformer ...
-3
votes
2answers
49 views

How does the secondary coil of a transformer affect the primary coil? How is it in case of Step-up and step-down transformer? Does it obey Lenz's law?

What changes will (of voltage, current, energy, power, etc) happen to the Primary coil, if an AC supply given to the primary coil, but; Secondary coil circuit is turned OFF (Open), Secondary coil ...
2
votes
1answer
65 views

Is there any Phase difference between the current in primary and secondary coils of a transformer?

Is there any Phase difference between the current in primary and secondary coils of a transformer? If I draw the diagram of a transformer, and try to find-out the direction of current using Lenz's ...
0
votes
1answer
42 views

Connect Two Transformer in Series

I have two transformers with a 220V primary and 12V secondary winding. What will happen if I apply 220V to the primary of the first transformer and connect the two secondary windings together? Will ...
0
votes
3answers
81 views

Is power rating of transformer determined by input or load?

Scenario: I have current carrying conductor with a current transformer around it. If the load is rated at 5V, 2A and only requires 2W of power, but the primary side conductor is carrying 100V 12A. ...
1
vote
4answers
85 views

If a step-up transformer increases voltage, then how current can be decreased ? is really the current in output is smaller?

If a step-up transformer increases voltage, then how current can be decreased ? If a step-up transformer increases voltage, then how current can be decreased ? (I'm trying to ask that, in case-of ...
0
votes
1answer
32 views

Low weight split core transformer on 11kVA transmission line

I've seen transmission line energy harvester's that utilise a split core transformer. Here is an example. However, I fail to see how this is possible when a transformer cores which are small enough ...
0
votes
0answers
47 views

What is the coupling coeffecient of a 10.7Mhz if transformer?

Does anyone have a rough range? I just need to be in the ball park. As an experiment, I'm simulating some if amp circuits in LTspice and it looks like they are very overcoupled when using a coupling ...
3
votes
1answer
50 views

Voltage drop on transformer's secondary winding experiment [on hold]

I've read things about it but I couldn't understand it. Let's say I have a 3-phase transformer and voltage of secondary winding is 230. When I keep adding 1k resistors (as load) in paralel it goes ...
6
votes
3answers
530 views

Audio transformer: What to do with an unused winding?

For the purpose of impedance matching and floating a single-ended, ground-referenced signal, I am planning to use an audio transformer like this one. Here's the schematic from the data sheet: My ...
1
vote
4answers
317 views

How safe is a current transformer

I acknowledge that the subject line indicates a "how long is a piece of string" style question, but I hope to make it more specific below. I have a "current transformer" (CT) purchased as part of an ...
0
votes
0answers
40 views

Tube Guitar Amp Audio Output Transformer Winding Theory

How do you determine the Output Transformer wattage needed on a tube amp? How do I work out the diameter of bobbin needed and primary/secondary wire thickness in an output transformer? How do I do ...
-1
votes
2answers
30 views

How to Series Wire Secondaries of a Multi Winding Transformer?

If I have a transformer that has 3 low voltage secondary coils (3V, 6V, 12V) and 1 primary coil (120V), how can I wire 2 secondaries in series? Can you show a diagram with a load? Is there such thing ...
0
votes
4answers
72 views

Audio transformer for 12V light emitting circuit

I'm working on transmitting audio through light using amplitude modulation of an LED, received by a solar panel connected directly to an active speaker. Something like this: simulate this ...
1
vote
4answers
358 views

Can a Transformer Have Multiple Secondary Coils?

Can a transformer have multiple, isolated, secondary coils from a single primary coil? Can each coil have a different voltage from the other? If so, is there any large negative effect, and what is the ...
0
votes
1answer
34 views

Current Transformer properties

I have a mains track (230VAC, 50Hz) on a custom PCB routed to multiple Solid-State Relays, and I want to measure the power going through this line. I'm looking into Current Transformers (CTs) to ...
0
votes
2answers
52 views

AC source resistance problem while simulating transformer in LTSpice

I am trying to build a Voltage quadruple circuit. But as per my requirement ,the source I will be using has a resistance of 25 ohms.As the input signal to too small I need to use a transformer to ...
0
votes
2answers
51 views

Decoding power supply regulation (42V from 5V)

I am referring below schematic where 42V is generated from LM78L05 regulator IC. But I am not able to get how LM78L05 can generate 42V? Which concept is used to get such high voltage from 5V regulator ...
2
votes
2answers
74 views

transformer windings

I have a 900 watts transformer from a microwave, this used to have a secondary voltage of around 2000 volts (for the magnetron) but I removed it. I wonder if by using 15 turn secondary that will give ...
0
votes
0answers
23 views

Need help on wiring/identifying transformers

I have always worked with those simple kinds of transformers, two wires for primary and two for secondary. For my project i need a transformer that can supply a minimum of 20 volts up to 30 volts or ...
3
votes
1answer
98 views

Can resonance increase frequency?

I would like to know what would happen if a capacitive load is connected to the secondary of a transformer. I simulated the circuit on Proteus. The inductance of the secondary coil was 0.1 H and the ...
3
votes
2answers
167 views

Why do people hand wind flyback transformers?

I'm intending on building this circuit, but re-specified for an output of about 150V @ 5mA. Enough to light two neon bulbs from a 12V supply. Why do flyback transformers such as the Wuther's seem ...
0
votes
1answer
63 views

full wave rectifier is not rectifying the wave properly

the following rectifier does not create a wave that is rectified evenly. according to the books this should work when using a centre-tap transformer. scales : (Y = 10ms/div) & (X = 5V / div) ...
1
vote
0answers
39 views

Wiring 2 audio output transfomer secondaries in series or parallel

I want to know if wiring 2 audio output secondaries in series is doable. See problems with this schem? Would parallel be a viable alternative?
1
vote
3answers
68 views

How can I know the rated current of a 6v transformer?

I've an old bulk transformer. It is 220V/6V. I Connected it to the basic rectifier circuit with a voltage regulator (7805) so that the output voltage is 5V. The transformer produces about 8V DC ...
0
votes
2answers
82 views

Why does my new 220V AC to 12V DC transformer only allow one Halogen light to work? [closed]

I'm trying to revive an old Ikea "Trettio" lighting set. The set is made up of a 220V to 12V transformer and 5 Halogen lamps connected to it in parallel. Remembering that the original transformer was ...
1
vote
1answer
40 views

Modeling a real transformer: why is the excitation branch in parallel?

In the above diagram, the parallel branch containing Rc and jXm represents the excitation branch. My question: I just can't seem to understand why the core loss current and the magnetization ...
0
votes
1answer
113 views

Best way to convert 5V DC to 110V AC at 50Hz for pdlc film drawing 2mA max. Size is the thing!

I'm working on a project in which I'm hoping to integrate several small segments of pdlc film, which starts off diffuse white/'frosted', turns clear when excited with 110V AC at 50Hz and is apparently ...
1
vote
2answers
32 views

Power Transformer with two Buchholz relays

In my workplace we have a power transformer, on its conservator tank there is a device like a Buchholz relay and its named as Atmo-Seal. What is the purpose of this device?
0
votes
1answer
27 views

Flyback transformer selection

I am designing a flyback converter using the PA3855.004NL transformer. Now, the datasheet screenshot is as shown below - . There is a value of 4.33 in the primary of the transformer. Is it the ...
0
votes
0answers
32 views

selection of transformer for flyback converter

I am designing a flyback converter. Now, necessary parameters are as stated - Vin(voltage to primary) = 17-32V, Vout(voltage to secondary) = 12V, Iout = 3Amps. Now, based on the above requirements, ...
0
votes
1answer
46 views

simulating a electrical transformer

My goal is to program a FDM simulation of a transformer. So, we have the coupled inductor model to start with ... However, if L1 = 1, L2 = 9, and coupling is perfect then M = sqrt(1*9) = 3 and L1 - ...
3
votes
2answers
40 views

efficiency calculation of dc-dc converter

I am designing a flyback converter circuit using the LT8302 flyback converter IC. Now, the efficiency of this chip is approx 85% as shown from the datasheet and the screenshot - The value of 85% ...
0
votes
2answers
47 views

Circuit Breakers in Low Voltage Chemistry Projects?

I'm currently using a circuit breaker for low voltage (6V) but high current (60A) electrochemistry projects. My bridge rectifier is rated at 60A max. I'm aware that circuit breakers work in counter ...
0
votes
0answers
40 views

Oscillator to drive transformer

I have a EI-19 T3535 1428 transformer and I'm trying to come up with a simple oscillator circuit to drive it for some high voltage stuff. I'd like to use only a single transistor rather then a 555 ...
0
votes
0answers
32 views

transformer insulation voltage test

I am trying to analyse the selection of a transformer for an automotive application. The specifications state that I must connect a load that should not be greater than 50% of the applied insulation ...
0
votes
2answers
44 views

Replacing power transformer with SMPS to charge SLA battery

Item: 25W amplifier/speaker with SLA batteries. I've done a little bit of modding in there. I doubt the warranty is valid any more, lol. In case you don't want to read the link about my modding, ...
0
votes
1answer
67 views

Why are split bobbin cores not used for distribution transformers (10kVA and up)?

Why are split bobbin cores not used for distribution transformers (10kVA and up)? They are available for low voltage but are not so popular for high voltage. Why?
3
votes
4answers
176 views

Confusion about dot convention in an ideal transformer

I am confused about voltage polarity and current direction in transformers , for example the equivalent circuit of the ideal transformer in figure(a) the instantaneous voltage polarity of the ...