Most of us have some basic knowledge of electricity because of the many electrical gadgets and appliances that we use every day. We know that when we flip on a light switch, electricity is supplied to a lamp and it produces light. We turn on the blender and the motor starts to turn. Flashlights use batteries as their power source and when they run down, the don’t produce enough electricity to light the bulb. In fact most of us have a slightly more advanced knowledge of electricity than we may realize. You have probably noticed that most electrical devices have two wires feeding power to them, or that light bulbs have a brilliant glow and they are very hot during operation. If you leave the car’s lights on overnight you know that the battery will be dead the next morning. You may also be aware that a car operates on 12 volts DC and the outlets in the house supply 120 volts AC.
The Electric Circuit
In order to better utilize the information presented in this article, it is necessary to have a basic understanding of electricity and how it can be applied to work with, or provide control for, mechanical devices. To better understand electricity, let’s first consider the basic electric circuit. All electrical circuits have two things in common, they have a power source and something that is
using that power, generally referred to as the load. In Figure the power source is a battery and the load is a light bulb. The battery supplies energy to the light bulb and the bulb’s filament glows. In this arrangement, the stored energy of the battery is transformed into something useful, light. Electrons flow from the negative terminal (–) of the battery through the light bulb filament and back to the positive terminal (+). To make the basic electrical a little more friendly, a switch is applied to the circuit. The switch is much like a valve for electrons. When the switch is open, as shown in Figure a, the flow of electrons is interrupted and the lamp is off. This mode is usually referred to as an open circuit. To turn the lamp on, the switch is closed and the electrons can flow again, as shown in Figure b. This mode is generally referred to as a closed circuit. The switch provides ready convenience in operating the circuit.
The Electric Circuit
In order to better utilize the information presented in this article, it is necessary to have a basic understanding of electricity and how it can be applied to work with, or provide control for, mechanical devices. To better understand electricity, let’s first consider the basic electric circuit. All electrical circuits have two things in common, they have a power source and something that is
using that power, generally referred to as the load. In Figure the power source is a battery and the load is a light bulb. The battery supplies energy to the light bulb and the bulb’s filament glows. In this arrangement, the stored energy of the battery is transformed into something useful, light. Electrons flow from the negative terminal (–) of the battery through the light bulb filament and back to the positive terminal (+). To make the basic electrical a little more friendly, a switch is applied to the circuit. The switch is much like a valve for electrons. When the switch is open, as shown in Figure a, the flow of electrons is interrupted and the lamp is off. This mode is usually referred to as an open circuit. To turn the lamp on, the switch is closed and the electrons can flow again, as shown in Figure b. This mode is generally referred to as a closed circuit. The switch provides ready convenience in operating the circuit.
