Voltage is the pressure or force from an electrical circuit’s power source that “pushes” charged electrons through conductors. The greater the voltage, the greater is its ability to “push” the electrons through a given circuit. Voltage is also called potential. The difference in voltage between any two points or terminals in a circuit is known as the potential difference, commonly called the voltage drop. There are two different voltages, AC (alternating current) voltage and DC (direct current) voltage. AC flows in both directions and is commonly used in electrical wall plug. DC flows in one direction and is commonly used by battery operated circuits. By using a special circuit, AC can be coverted into DC and vice versa. In this guide, we will only be learning circuits in DC.
The unit for voltage or potential difference is volt with a unit symbol of V. When working with formula, the symbol for voltage is V or E.
Formula, V=IR or E=IR ( Voltage = Current x Resistance) - Ohm’s law.
How to Measure DC Voltage
By using a multimeter, turn the mulimeter’s knob to the voltage range. Touch the RED (positive) probe on one of the point and the BLACK (negative) probe to the other point. The display tells you the potential difference (voltage) of the two points in Volts.
In the above example, two 1.5V AA batteries connected in series has a voltage of 3V.
If your multimeter is not an auto-ranging multimeter, always set the range to the highest first, then work downwards until the desired reading is achieved.