: a very large amount or number: an amount that is much greater than what is necessary. A plethora of books have been written on the subject. a plethora of information. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples. a very large amount or number: an amount that is much greater than what is necessary. A plethora of books have been written on the subject. a plethora of information. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.
Ohm's law defines the relationship between the voltage, current, and resistance in an electric circuit: I = V / R. The current is directly proportional to the voltage and inversely proportional to the resistance.
In a series circuit, the voltage across a resistor is directly proportional with its resistance (Et= I(Rint+R). That means in a series circuit the voltage across the resistor will increase when the resistance in increased, while the current will reduce. A power source has internal resistance (Rint) which will be in series with the resistor R. So even though your resistor is connected across the power supply, the internal resistance Rint is in series with it.