The formula for calculating total current in a DC circuit is I = V/R, where I is the current in amperes, V is the voltage in volts, and R is the resistance in ohms.
The resistance of a circuit component can be calculated using Ohm's Law, which states that resistance is equal to voltage divided by current (R = V/I). Alternatively, the resistance can also be calculated by measuring the voltage across the component and the current flowing through it, and then using the formula R = V/I.
The unit of measurement for resistance is the ohm (Ω). This unit is named after the German physicist Georg Ohm, who first discovered the relationship between voltage, current, and resistance.
No, it is not possible to calculate voltage without knowing the current or resistance in a circuit. These three variables (voltage, current, and resistance) are interrelated and are all necessary for calculating the values of the others using Ohm's Law.
To measure voltage and current in a circuit, you will need a voltmeter and an ammeter, respectively. These are electronic instruments that are connected in parallel and series, respectively, to the circuit to measure the voltage and current. It is important to always follow proper safety precautions when using these instruments.