- #1
IanT
- 5
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I am confused over something about voltage and current. A transformer increases/decreases the voltage in a circuit and does the opposite to the current. The current times the voltage has the same value before and after. This however, seems to go against the well known equation V = IR (the voltage equals the current times the resistance). If a step-up transformer increases the voltage and decreases the current, doesn't the resistance have to increase A LOT in order for V = IR to be valid?
Another thing is how the voltage affects the brightness of a light bulb. My textbook says that a light bulb connected to a circuit after a step-up transformer is brighter than one connected before it. But although the voltage is higher, the current is lower, meaning that the joules per second before and after going through a step-up transformer is the same. So why is the light bulb brighter?
Thanks in advance.
Another thing is how the voltage affects the brightness of a light bulb. My textbook says that a light bulb connected to a circuit after a step-up transformer is brighter than one connected before it. But although the voltage is higher, the current is lower, meaning that the joules per second before and after going through a step-up transformer is the same. So why is the light bulb brighter?
Thanks in advance.