I dont think this is normal behaviour of a transformer

160

03:46:07

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published 9 years ago

nimb

9 years ago

Nice job

thebugger

9 years ago

It is. Until the magnetic field builds up even DC will trigger some voltage at the secondary. A 10H tranaformer is quite large and it'll require a given amount of time fore the field to build up. Then it becomes static and no current will flow through the secondary.

TakMashido

9 years ago

A transformer storage energy(3V there) and work in a not static Voltage. Diode have 2V max. Change a battery to 2V to see it.

dylanmissuwe

9 years ago

I don't think this will happen in real life

hurz

9 years ago

Turn the led around and you probably understand better ;-)

hurz

9 years ago

http://everycircuit.com/circuit/5379954345771008

meicher

9 years ago

If you consider the transformer as a special pair of inductors it might make more sense. The voltage of an inductor is V=L * di/dt. Basically a very rapid change in current creates a large voltage drop across the inductor. It's the change in current that makes the part interesting, due to creating and collapsing magnetic fields. Your 1:1 transformer just takes what's on the primary side and puts the same voltage on the secondary side. Try adding a RC filter after the switch and play with the R value while looking at the voltage.

dylanmissuwe

9 years ago

Yea, but my point is that this will never happen in real life even when i put a resistor between the source and button to limit the current, same thing happens

hurz

9 years ago

If you have the same almost perfect components (coupling coefficient 0.999, voltage 3V zero ohm resistance, and 10H primary with only 100mOhm) it will work the same way in real!

yra

9 years ago

Feeding the transformer with DC and breaking the connection will produce a large spike in voltage same as a high tension circuit in a car ignition system. As meicher said magnetic fields, this is normal. As hurz said same as real world.

yra

9 years ago

DC input makes a electro-magnet, a changing fields makes a transformer.

meicher

9 years ago

There are parasitics in real components that should be modeled if that's your intent. Regardless, if the rate of change in current produced is high enough, a large voltage generated across the primary winding of the transformer can lead to the destruction of the LED. As the switch opens and closes, the rate of change in current (aka slope or derivative) approaches infinity which means a very large voltage will be generated. An RC network helps to control the slope but you'll need to examine the closing and opening effects separately since they are somewhat different. Good luck.

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