Electrical – If V=IR Why are voltage and current interchangeable through a constant resistance


I hear people say things like "I only put 5 amps through the circuit but I put a bunch of volts". I don't understand how this is possible if V=IR. Lets say you have a circuit with 5 ohms of resistance so V=I(5). The amount of voltage and current I am allowed to put through it has to be proportional.

Can anyone can give a good intuitive answer (don't go too in depth with math) that is understandable?

Best Answer

If you re-read your question, then it sort of answer's itself. Yes...in a pure DC circuit, Ohms Law is King, and so V=I*R. But you stated they said "I only put 5 Amps through the Circuit....so if they put a constant 5 Amps through the circuit, then the voltage will be the current times the resistance. Since they didn't state the Resistance, then the value of the Voltage may be a "bunch of Volts"....if the resistance is high enough. Simply put....under normal everyday simple DC circuits....most people drive them with either a Voltage or Current Source...but typically not both. If they drive the circuit with a Current, then they will see the Voltage go up proportionally. So I believe maybe they didn't mean they "Put In" both Current and Voltage, but they put in Current and Measured a Bunch of Voltage...or Vice Versa.