5.1 Voltage, Resistance, and Current
1. You can calculate the current in a system without shutting it down and measuring it. You can use "Ohm's Law" if you know the voltage and the resistance. The formula is:
E=IRThe voltage equals the current times the resistance. We can rearrange the formula as well. Current equals the voltage divided by the resistance, and the resistance equals the voltage divided by the current.
2. You can use this formula for an entire circuit. You can also use it for a distinct part of a circuit.
3. There can be more complex situations where the value of one resistor is known but not the value of another. In such cases, knowing algebra will come in handy so that you can set up an equation and then solve for the unknown.