In this video, I showed how to test and characterize unknown signal/pulse transformers with a function generator and a multimeter. More information can be found at: www.kerrywong.c...
It's been over 40 years since I studied this stuff in tech school, and as usual I got into a niche where I never used 90% of what I was taught. Now I'm retired and getting back into electronics and reviewing topic by topic, component type by component type applicatiopn by application.
+Henri “Ketturi” Keinonen Also using a sweep and synchronising the scope the to signature generator, you could see how the voltage changes with frequency.
@@Chevroletcelebrity yes you can, when 2 of them go the same direction the polarity will be the same when you got a probe on both, it'll be opposite polarity (or phase shifted 180 degrees in other words)
This technique will provide a rough start. Determining actual primary, current capability, insulation resistance, actual turns ratio, and other parameters will require more digging.
I like this video and I'd like to know more about how other parameters of the transformers can be characterized with non expensive tools. For example you show at which frequency the transformed voltage is at maximum but that may not be the best operating point for maximizing power transfer (which also depends, i guess, on the characteristics of the load)
Ok, this video is actually OK after watching several that wasted my time :D. You've mentioned smaller transformers, what about those with 380V on the primary like Hlaft Bridge ones yet still HFs? Can you measure them the same way? If not, what way?
When testing these transformers, if you don't know what type of transformer you have and you don't know which side is the primary and which is the secondary, could it happen for example that you connect the test signal to the output of a step-down transformer and you actually measure a stepped-up voltage at it's input?(which in this case where connected backwards has become an output) mistaking that transformer for a step-up one.
+VoltLog The designation of primary and secondary is usually arbitrary. So if you are using a say 110 V to 12 V transformer, you can either supply 110V to is 110V winding (primary) and get 12V out, or you can input 12V and get 110V. And in the latter case 12V would be your primary. So for a step down transformer you can also use it as a step up transformer and vise versa.
While it is true that a transformer can be used as either step-up or step-down, those laminated core transformers you have shown are designed to step down the mains voltage of 110V to 230V (depending on where you live) to the voltage required by the circuit and are meant to operate at 50 to 60Hz. The fact that they can be operated up to several thousand hertz is simply a matter of the cores capabilities and not it's ideal operating frequency. While it is important to choose a core type based on the operational frequency of your circuit, that does not imply that you must tune your circuit to that of the transformers ideal operating frequency.
Hell yeah I'm going to subscribe. Thank you so much. I think I just learned more than a semester of college here. Could you please tell me how you know which side of the Transformer is the output and which side is input? because I don't think you clear that up in the video. And I desperately need to know
There isn't really an input or output as transformer is bidirectional and depending on your use. You can use this method to figure out the rough turn ratio between to two windings.
+DextersLab2013 The designation of primary/secondary is arbitrary in this case as it depends on what you want to use this transformer for. In the multiple winding scenario, if the windings are tapped, you can infer the phase of the winding by measuring the voltage across different taps. If the windings are separate, you can identify the phase either by using a scope or connect one side of the winding with a "reference" winding and infer the phase with respect to the reference via the generated voltage.
How pulse transformer behaves with pulse input i tried to check but i don't know end result. My input waveform is getting squeezed as i connect to transformer.
i think you have to saturate the transformer to find out its best frequency, not that it is designed like that but for this example results are not correct , if i am correct .
Rather too much emphasis on frequency. Many people just want o confidently ID the primary & secondary terminals & what happens if accidentally thedeiign with say mains voltage?
Hi Kerry, I am trying to learn about these transformer. I really like the way you explain it. Thank you. However, I do not have a function Generator but I have a signal generator from 0.1 to990 MHz will that work?
I have a SMPS transformer E1614 controlled by iW1677-01 that transforms 310 Dc (after rectification ) to 5V DC. The iW1677 switching IC operating frequency ranges from 2.1KHz to 72Khz. How can i test this transformer separately just as you did in the above video and what frequency and Vpp do i need to select in the function generator? Btw , when i'd selected 2.1Khz frequecny and 1Vpp sinusoidal Vave , the output was almost 10mV.
No. You are probably better off by inputting into the secondary (say 1Vpp) and measure the output from the primary. You should see around 60V on the primary (depending on whether the 5V figure is regulated the actual voltage may vary)
Here are the measurements: 6V transformer: primary: 1Vpp at 2Khz output 6mV at 25Khz , output 29mV (after 25Khz output starts decreasing) When i switched the supply to secondary side Seconday: 1Vpp at 2KHz output at primary 12mV (aprox) at 25KHz output at primary 60mV ====================================================== What does the above measurements imply :)
