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
9 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?
0
votes
0answers
40 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 ...
0
votes
1answer
28 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 ...
0
votes
2answers
94 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 ...
0
votes
4answers
88 views

What is this electronics component?

What is the yellow component shown here? This is off a Outlet USB phone charger.
0
votes
1answer
32 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. ...
0
votes
0answers
53 views

Generation of elctricity from sound [closed]

which is better to use among step up transformer and cascade amplifier to convert 50mV to 2.5V. then what are the other devices to be used to get 2.5V?
0
votes
0answers
23 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
31 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?
0
votes
3answers
62 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
259 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
votes
2answers
54 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 ...
0
votes
3answers
91 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
votes
0answers
39 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 ...
0
votes
2answers
82 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 ...
0
votes
0answers
22 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
76 views

circuit diagram for uninterrupted usage of a 12volt 1amp device using 12 volt 7ah battery with auto charging and full charge cut off

I have a modem which runs at 12Volt 1Ampere , also I have an UPS battery of 12volt 7Ah. I need to design a circuit so that during power outages my modem works from the battery. also a circuit ...
0
votes
2answers
60 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 ...
0
votes
0answers
18 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
46 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
60 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 ...
-2
votes
3answers
131 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?
0
votes
3answers
68 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
55 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
121 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
votes
2answers
40 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, ...
0
votes
1answer
55 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
votes
1answer
51 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 ...
1
vote
1answer
63 views

Removing neon transformer center tap?

I have recently acquired an old neon transformer (rated 12kV) for conducting some low temperature plasma experiments. It is the mid-point grounded style with a center tap on the secondary coil. I had ...
1
vote
2answers
84 views

What is the low frequency limit for ferrite cores in audio applications?

I've searched high and low through the ferrite magnetics catalogs and this list for an answer and can't find data on ferrite core permeability below 10kHz. My application is for audio use and I need ...
0
votes
3answers
82 views

1:1 and flyback transformer at low frequency and high temperature

I am designing a circuit in that I need 1:1 and fly-back transformers at low frequency (0-100kHz) and high temperature. Can anyone help me with these? I am looking for voltage being handled around ...
1
vote
3answers
64 views

Transformer: loaded vs open-circuited vs short-circuited

I am trying to understand the working principle of current and voltage transformers. I understand that V.T. and C.T. are basically just transformers, but I can't understand how secondary winding ...
0
votes
1answer
63 views

Question on capacitive circuit in practice

If we were to build a circuit, let's say with a power source of 120V AC going into a transformer which steps that up to 10kV @ 30mA, the output of which would be connected to a capacitor with a ...
0
votes
1answer
87 views

Is a 115V rated transformer expected to accept US mains voltage (120V)?

< question completely reworded since people thought I was looking for appliance repair instructions > Many "Power Transformers" are rated at 115V or 230V. It seems to be the most popular rating. ...
2
votes
1answer
55 views

Transformer symmetry

Thinking of using a Murata 78602/3C, which is a 1:1:1 pulse transformer. Described as two primaries and a secondary. My question is whether these terms for primary and secondary are arbitrary given ...
0
votes
0answers
33 views

Compensation of leakage reactance in high frequency transformer

I have a designed a toroidal high-frequency (12/350V, 800VA, 100kHz) transformer with a 50uH magnetization inductance. I measured the leakage inductance by resonating it with a 1uF capacitor. The ...
3
votes
1answer
58 views

Higher current output from transformer?

I just received a battery charger in the mail, but I forgot to purchase the power supply. I was wondering if it was possible to use a transformer from an old lamp to supply the charger instead: The ...
0
votes
1answer
61 views

Using a 15V input with either a 24V or 12V input transformer?

I have a circuit built and I have an output of 15V AC. I want to step it up to at least 100-120V. Now all I can find is 12V or 24V to 117V transformers. Let's say both transformers are rated at 48VA. ...
0
votes
1answer
96 views

Simulating transformers in Proteus

This is a spinoff of the thread found here: Proteus 8 error: Timestamp too small I have found that a lot of the problems I have been running into were due to the feedback transformer coils not being ...
1
vote
3answers
295 views

Why does the USA use 110V and UK use 230-240V?

Why does the USA use 110V and UK use 230-240V? What are the advantages? Explain me with calculation. Why do they use different frequencies like 50Hz, 60Hz? What is the reason?
0
votes
1answer
59 views

Transformer size?

How can I set the size of a transformer for a cooling fan project? The load is 100A, the power supply is 125A, we will take input from 230Ac 60Hz. Incoming two phases and outgoing also two phases but ...
1
vote
1answer
125 views

Can I run 2 transformers in series?

I need a 15kV or higher power supply. I found 2 used neon sign transformers rated at 10kv. Can I use both of them and connect the secondary coils in series to get 20kV? I am not sure if 15kV isn't ...
0
votes
0answers
62 views

DC Voltage of a 12V AC transformer after rectification

I want to drive relays using Method 2 of the following question: What is the most economical way to drive an array of single coil latching relays? This basically means that any time the relay is ...
3
votes
2answers
123 views

Boost converter 100mV to 5V

I am trying to design a boost converter which converts 100mV to 5V. 100mV is the minimum I get from my DC motor which I used as a generator and max is around 1V. I tried searching for the IC's which ...
0
votes
1answer
51 views

60 V AC behind DC step-down

I have various power supplies in the range of 5 V DC to 19 V DC which still have about 60 V AC pollution in their output. This makes me get zaps from the attached devices quite often. Is there a way ...
1
vote
1answer
79 views

Autotransformer design — how many turns?

Let's say I have a 25 ohm resistor, a 28MHz oscillator, and some wire with which I can make an autotransformer. The goal: make the oscillator see a 50 ohm resistance (or something reasonably close to ...
1
vote
0answers
87 views

Designing an efficient PSU

I am designing a PSU capable of producing 5 watts @ 5V 1A. The design will power about 12 RGB LEDs (totaling about 400mA @ 5V) and a audio class D 1.4 W amp. Space is no issue but efficiency and cost ...
1
vote
2answers
75 views

Power Transformer Rating Question

I am trying to understand power transformers practically. I have an inverter that outputs 12V AC. I want to step this up to 120V AC. My load will just be a resistive load that takes no more than ...
0
votes
1answer
95 views

Flyback NE555N driver and mosfet overheat

I have built a small and very simple flyback SMPS based on NE555N IC. The circuit exactly I did built from is shown below: It works nicely for small loads. However I have some issues with it: ...
1
vote
2answers
101 views

Loop count in a current transformer

I was reading this article about current transformers. It says that, the loop count is 1 when the wire is just passing through the core. And there are 2 loops when it is wound for once, and 3 loops ...