- #1
Tyler184
- 11
- 1
- TL;DR Summary
- I’m attempting to create an experiment to induce EMF from one coil inductor into another, yet being able to relate my observations with my math I did so I could control certain variables.
Hey guys, for some context, I’m a high schooler doing an experiment as a passion project, my issue today is an aspect of my project.
Anyhow, my ultimate goal is to be able to “remodulate” radio signals by converting them from AM to pulses in a magnetic field strength. While I bet there are many ways todo that, my specific approach requires the use of two inductors relationship via EMF. However, it is important to note, I’m not going straight in and remodulating radio signals just yet, I want to test the theory behind them first. Which is where this experiment is coming from.
The experiment consists of two inductors as previously mentioned, perpendicular to each other (one horizontal and one vertical), and I power the horizontal one to create a magnetic field and then I stop powering it after giving it some time to build magnetic energy and as the current drops so does magnetic field intensity therefore the flux drops and it results in a change in flux with respect to time therefore inducing emf into the second, vertical inductor.
Subsequently, I attached two probes of a MM at the end of the vertical inductor to measure the induced voltage. What I found quite odd was immediately after I powered off the horizontal inductor and began measuring the voltage in the vertical, I measured no induced voltage yet a compass I had on standby, was pointing towards it even as I revolved it around the vertical inductor showing it had its own magnetic field, and the only way it could’ve gotten that was by being induced with an EMF which then would store it as magnetic energy. Compasses are very sensitive unlike an MM so perhaps my MM didn’t catch the induced voltage although the MM was on mV mode therefore it’s unlikely it didn’t catch it cause the emf was probably in the mV range.
One thing I would like to mention as it’s quite important to know, is that I powered the horizontal magnetic field via a short (no resistance) by wiring up some AA’s batteries in series to obtain 7-8 V. I originally had resistors but I found they significantly hindered the strength of the magnetic field, on top of the fact I’m struggling as is to get proper readings with my MM.
Anyway, I attached a picture of my setup so you can see it. The core is a drill bit with a 2000 relative permeability I presume (steel core). The horizontal magnetic field is 175 windings at an estimate, 178mm in length, with a 5mm core diameter. And the AWG of the windings is 22. The vertical inductor is 252 windings, 56mm long, and 2.5 mm core diameter. With a AWG of 30. Moreover, the vertical inductor is held by a magnet in this picture however that was just to hold it for the picture so you can see how it was positioned during the experiment.
Additionally, with the magnet seen in the picture I did a side experiment by taking off the vertical inductor and varying the distance between the magnet and vertical inductor(basically if the magnet is in one hand and the inductor is In the other, just imagine bringing my hands further and closer together). By doing it I was able to develop a magnetic field powerful enough to pick up a small screw. I presume the magnet induced an EMF by varying the magnetic field strength/field flux.
Next, while the inductor still had its magnetic energy stored I decided to use my MM to again measure any possible induced voltage but I measured nothing which confused me. I’ve gone to my teachers who say my MM works just fine and isn’t the issue.
Moreover, my math also isn’t making any sense, as I’m predicting an EMF of 30-0.3V within 5 time constants of not powering the first magnetic field(yes volts, not mV) which is obviously wrong. I feel it would be best to fix the observations first then I’ll further discuss my math as to not make this thread too long.
Anyhow, my ultimate goal is to be able to “remodulate” radio signals by converting them from AM to pulses in a magnetic field strength. While I bet there are many ways todo that, my specific approach requires the use of two inductors relationship via EMF. However, it is important to note, I’m not going straight in and remodulating radio signals just yet, I want to test the theory behind them first. Which is where this experiment is coming from.
The experiment consists of two inductors as previously mentioned, perpendicular to each other (one horizontal and one vertical), and I power the horizontal one to create a magnetic field and then I stop powering it after giving it some time to build magnetic energy and as the current drops so does magnetic field intensity therefore the flux drops and it results in a change in flux with respect to time therefore inducing emf into the second, vertical inductor.
Subsequently, I attached two probes of a MM at the end of the vertical inductor to measure the induced voltage. What I found quite odd was immediately after I powered off the horizontal inductor and began measuring the voltage in the vertical, I measured no induced voltage yet a compass I had on standby, was pointing towards it even as I revolved it around the vertical inductor showing it had its own magnetic field, and the only way it could’ve gotten that was by being induced with an EMF which then would store it as magnetic energy. Compasses are very sensitive unlike an MM so perhaps my MM didn’t catch the induced voltage although the MM was on mV mode therefore it’s unlikely it didn’t catch it cause the emf was probably in the mV range.
One thing I would like to mention as it’s quite important to know, is that I powered the horizontal magnetic field via a short (no resistance) by wiring up some AA’s batteries in series to obtain 7-8 V. I originally had resistors but I found they significantly hindered the strength of the magnetic field, on top of the fact I’m struggling as is to get proper readings with my MM.
Anyway, I attached a picture of my setup so you can see it. The core is a drill bit with a 2000 relative permeability I presume (steel core). The horizontal magnetic field is 175 windings at an estimate, 178mm in length, with a 5mm core diameter. And the AWG of the windings is 22. The vertical inductor is 252 windings, 56mm long, and 2.5 mm core diameter. With a AWG of 30. Moreover, the vertical inductor is held by a magnet in this picture however that was just to hold it for the picture so you can see how it was positioned during the experiment.
Additionally, with the magnet seen in the picture I did a side experiment by taking off the vertical inductor and varying the distance between the magnet and vertical inductor(basically if the magnet is in one hand and the inductor is In the other, just imagine bringing my hands further and closer together). By doing it I was able to develop a magnetic field powerful enough to pick up a small screw. I presume the magnet induced an EMF by varying the magnetic field strength/field flux.
Next, while the inductor still had its magnetic energy stored I decided to use my MM to again measure any possible induced voltage but I measured nothing which confused me. I’ve gone to my teachers who say my MM works just fine and isn’t the issue.
Moreover, my math also isn’t making any sense, as I’m predicting an EMF of 30-0.3V within 5 time constants of not powering the first magnetic field(yes volts, not mV) which is obviously wrong. I feel it would be best to fix the observations first then I’ll further discuss my math as to not make this thread too long.
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