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Re: transformer demonstration



What !!!! you connected a small coil (only 200 turns) with no core and expect it to not overload the power supply? The current is too high, because the inductance of your solenoid (the primary) is too low to limit the current; At a few kHz it might be enuff. Put a bunch of iron rods (fill the space) inside the solenoid and it'll (I think, I'm too lazy to calculate the inductance) work fine.

Regarding the load, I know of no gas discharge lamp that will operate on 6 V. Most neons require ~ 90 V.. (depends on the pressure; in any case a min. of the ionization V. is required.)


In sum: you problem is not with the load, it's with the inductance of the primary.

bc

P.s with a hot cathode a gas lamp might work at such a low V. but then that's just artificially increasing the V!!!

Justin Parke wrote:

I need some help in debugging a classroom demo illustrating a transformer. I don't have an actual transformer, I am attempting to use two coaxial solenoids.

First I connected a (200 turn, approx.) solenoid (about 10 cm. long) to 6.3 V AC. I nested a second (approx. 100 turn) solenoid of the same length inside the first. Across this solenoid I connected a light bulb. I don't know the specs on the light bulb; it is actually a light box used in optics experiments. It works just fine when connected individually to the 6.3 V AC supply. When the power suppply is turned on nothing happens except that after a few seconds the circuit breaker in the power supply trips.

Next I added a second light box in series with the primary solenoid to prevent the current from becoming too high.

What I want to do is to light the light bulb in the secondary by an induced voltage from the primary. I must be overlooking/ignorant of something important here.

Any suggestions?

Justin Parke