Hello,
First of all, what a great site! I am in college physics, and electronics really grabbed my attention (granted the class is only algebra based, and all of this is a bit overwhelming). I would love to pursue electronics further, but I need solid foundations first. A huge 'Thank You!' to everyone for their responses and support in advance! I saw this during my investigation in trying to figure things out:
I understand these are very elementary questions (and perhaps on the completely wrong thought process), and I understand there are about 100 questions in there. This would help me so much to clarify these concepts, and the videos, worksheets, etc. didn't completely clarify things for me.
A million thanks for your patience and shared knowledge!!!
First of all, what a great site! I am in college physics, and electronics really grabbed my attention (granted the class is only algebra based, and all of this is a bit overwhelming). I would love to pursue electronics further, but I need solid foundations first. A huge 'Thank You!' to everyone for their responses and support in advance! I saw this during my investigation in trying to figure things out:
So if the ratio were 200:1 instead of 20:1, we would see a secondary 1.2V and 10A. Could this even light the bulb with only 1.2V? Would the wire filament get way too hot with 10A? If power is the same, why is this useful? If transformers are inside of things I plug into the wall to step down voltage for lower voltage-requiring electronics, then won't they carry higher currents? Or is current restricted by resistors in that little plug box I use to plug in? Why can't they just dissipate the voltage with resistors?Although I'll not fault anything that has been stated so far, let's go with a more simplistic view of the transformer. There are many applications for transformers of various designs, but in this case we are concerned with transferring energy from the high voltage or source side of the transformer to the low voltage or load side of the transformer. The main thing to remember is that you are transforming energy, or power (watts) from one side to the other.
Assume that the high voltage side of a transformer is energised at 240 volts and the low voltage side is rated at 12 volts. (that is a ratio of 20 to 1 by the way, remember that) Connected to the low voltage side of the transformer is a lamp which is a 60 watt load. With 12 volts applied to the lamp, the current draw would be 5 amperes. (E*I=P) We now know the quantities that are present on the low voltage, or secondary side of the transformer.
On the high voltage side the quantities will be different or course, but in proportion to the winding ratio of this transformer. (remember the 20 to 1)
Remember that the power in to the transformer has to equal the power out.
If that is true in this case, then the load on the transformer is 60 watts, the voltage on the primary side of the transformer is 240 volts then the current in the primary winding must be .25 amperes. Sure enough, .25*240=60
In keeping with your original post, notice that the current flow in the high voltage winding is less than that in the secondary winding. It is less by a factor of 20. There you have it. High voltage-low current. Or, if you prefer, low voltage-high current. Just remember, you transforming energy(watts) from a high voltage source to low voltage load. Watts in to the transformer must equal the watts out.
Hope this helps.
I understand these are very elementary questions (and perhaps on the completely wrong thought process), and I understand there are about 100 questions in there. This would help me so much to clarify these concepts, and the videos, worksheets, etc. didn't completely clarify things for me.
A million thanks for your patience and shared knowledge!!!