1. A

    transformer core explanation required

    hello everyone, this is a stupid question but if anyone can answer this, i'd be so grateful. the question is about the transformer core. take a simple EI laminated silicone steel core for example. we know primary winding magnetises and secondary demagnetises. and at a some point an equilibrium...
  2. 7

    What should be connected to the 5th pin of transformer?

    Hello, I'm an electronics engineering student, currently trying to design a circuit that includes a transformer. I'm using Orcad's Capture (Pspice) software. When I searched "Transformer", this part appeared as 'Generic Transformer', the part name goes by 'PWMXFM'. It has 5 connections, I...
  3. Maxxon

    Having some voltage issues with my Google Nest Doorbell...

    I installed a google nest doorbell and it mostly works. I am having some issues with the external digital chime I setup, so I tried to talk to tech support. However, they are very hard to talk to as they don't really know anything about electricity and how it works. They're just basically...
  4. Younes Thabet

    How to calculate primary current in an smps transformer?

    Hello all, I have the following 12V center-tap transformer with below number of turns, I used (Np/Ns = Vp/Vs) to calculate output but i didn't get 12V although transformer specification says it's 12V. Can someone point out where I have mistaken? Also How can I calculate primary current given...
  5. garrettb11

    Unique Delta-Wye Transformer Fault

    I am trying to determine what the secondary voltages would be after the following fault occurred. Basically one phase energized two bushings on a delta-wye transformer. I believe it would be something like this but I am not entirely sure.
  6. Younes Thabet

    What are design requirements of SMPS transformers need to be provided for manufacturer!?

    Hello all, I am designing a 12V, 18W Flyback SMPS and i can't figure exactly the characteristics of high-freq transformer (Both Core, Bobbin) to send for transformer manufacturer!! Can someone already went through these procedures guide me little bit!? Regards,
  7. S

    Altium Designer "Flip" function not working correctly?

    I am designing a planar transformer in Altium. I am using the planarTX plug-in I found on GitHub which is helping things move along a lot faster - however it only has the capability of creating spirals in a single direction. This means it is not feasible for creation of a series connected...
  8. jacob_c

    Can you give me some hint for my PSPICE project?(transformer, diode)

    The project is about designing a transformer that converts 22V AC to 1V AC and connect it to voltage doubler as V_in So here's my schematic and simulation result. I'm having trouble with analyzing the result. The D1N914 diode that is recommended for this project, had Vd,on of about 930mV when...
  9. B

    Transformer high voltage spikes

    Hi all, I'm using a 220V - 24V transformer as a supply of 24V AC - 18V DC converter which is my own design. Since I cannot control the output of the transformer I put a crowbar circuit in the DC converter circuit as a precaution for the high voltages and it triggers around 42-43V DC. So the...
  10. I

    Weird transformer pls help me identify

    Hi! I Have a transformer that has a 0V 185V 220V 255V Marking on the primary side and 7.1V 0 7.1V and a low power 19V unfortunately i dont have a tester to check the transformer's 220v input and i dont wanna just plug it to mains because im pretty sure its gonna cause chaos, pls help! The...
  11. P

    Transformers vs Converters: Weight

    I'm curious why, if I want to buy say a 24V, 75VAC transformer (so a little over 3A at 24V), I'm looking at a pretty chunky piece of iron. On the other hand, I can find a ~24V laptop power supply that can handle 3+A and it doesn't need nearly as much iron to make that happen. I get that the...
  12. J

    Block transformer ratings interpretation

    I have a small Block FL4/12 transformer laying around for which I expected the output to be 12V RMS on secondary side but I'm measuring different values. It is a dual winding transformer on primary as well as secondary side with ratings 115V for each winding primary side and 12V for each winding...
  13. Rahulk70

    Identifying the input power leads of a salvaged UPS transformer for projects

    Hello everyone, I'm writing this post mainly to help others who have had asked many questions in the past how to figure out the input supply leads (115V or 220V AC wires) on a salvaged UPS transformer. These transformers from a UPS are quite bulky and quite powerful and can be very useful in...
  14. S

    Calculating secondary turns on transformer

    I am designing a transformer for a high voltage converter. The topology is a push-pull converter. My method is to have a 200V primary generate 4x750V secondary windings, each feeding a voltage multiplier to generate 1500V. Then connect these in series and generate the final 6kV. So far I have...
  15. Dan Aronin


    Hi all, I'm interested in assembling a circuit that will be capable of CONVERTING 220V TO 5V@2A 10W (Edit: AC TO DC) The issue is that I manage to find only PRICEY, HUGE TRANSFORMERS like this. I know there are small circuit (example) available for purchase, so my question is - Where can I...
  16. S

    How to determine component values and switch dead-times in a fly-back passive snubber circuit

    I have been studying the use of snubber circuits within flyback converters and other hard-switched converters, and doing some simulations to see the results. I have came across one type of snubber called a passive snubber circuit, which uses no resistor and instead some additional passive...
  17. kubeek

    Great tool for transformer calculation

    Hi guys, I just found a great website that lets you easily calculate the parameters of a transformer or inductor, given the core parameters and material. I was trying to choose some suitable core to make a flyback for geiger counter, and this really came handy instead of doing a bunch of...
  18. I

    Designing Step Up Flyback Transformer Help

    Hi. I am trying to build a power supply which output is 2000VDC and 20mA (40W) input is 220V ac (european input). I thought I can use flyback transformer. And I started to design. I selected duty cycle as %50 and frequency as 50kHz (actually I don't know how to select frequency and duty cycle...
  19. H

    Low AC Current Sensor Circuit (current sensor)

    I am having issues finding a Variable current sensor switch that will precisely sense within the AC current ranges of 0-1 Amps (Test Range 0.001-0.2 Amps). Once the range of (0.001-0.2A) is sensed, I would like to trigger an alarm. Any suggestions on what I could use to sense such low AC currents?