problem about transformers (1 Viewer)

[mmkardart]

Can anyone explain this? =]
1. In a transformer, what would be the effect of INCREASING the number of turns on the secondary coil, with the same light globe attached?

OK.. so the output voltage would be higher...

BUT how about this....

• With the same lamp, the current would be more and hence more power would be produced and the lamp would be brighter. (Why?)
• A greater output current would result in a greater input (primary) current (Why?)​

2. In a transformer, why is it that ... If the load (resistance) on the output is decreased, the output current increases accordingly and the input current increases?

please help >___<
​

 

[thehootman]

Ok. Power = VI agreed?

As the globe attached has a (lets assume) constant resistance, as we increase V (from more coils) it will result in more current going through the globe, and thus more power (P = VI).

Now, as the primarly current induces the secondary current, any increase one way or the other affects the primarly coil.

I wouldnt really worry about transformer q's. Usually they are very simple, straightforward "calculate the output voltage" etc

 

[jlnWind]

Can anyone explain this? =]
1. In a transformer, what would be the effect of INCREASING the number of turns on the secondary coil, with the same light globe attached?

OK.. so the output voltage would be higher...

BUT how about this....

• With the same lamp, the current would be more and hence more power would be produced and the lamp would be brighter. (Why?)
• A greater output current would result in a greater input (primary) current (Why?)​

2. In a transformer, why is it that ... If the load (resistance) on the output is decreased, the output current increases accordingly and the input current increases?

please help >___<
​

This is probably a late reply, but i guess its good for revision

I dont get the first one, where is light bulb, before or after the transformer
cos if n increases, doesnt I decrease?

For 2) P=VI but V=RI there fore P=I²R Therefore assuming
power is conserved with an efficient transformer
I²R = I²R
If R increases on decreases RHS, I increases on RHS ( to conserve power)
But VI = VI so when I increases (as turns do not change so V does not change)
the I on the LHS also increases...
Hmm im probably wrong, so if anyone can correct me thatd be good

 

[Enteebee]

OPTIMUS NOOOOOOOOOoooooooooooooooooooooooooooooooooooooooooooooooo