There are many types of refrigerators, but most refrigerators use direct current, such as 12V DC Freezer , today we come to understand the current vividly.

Beginners learning electronics will feel that electricity is too abstract, so we can compare electricity to familiar things, because electricity is very similar to water flow, so we can think of "electricity" as "water", and "circuit" is equivalent to "waterway". Of course, we can also use other things as a metaphor.

Recall that when the water in the canal was flowing, we were standing somewhere in the canal. Does the amount of water flow through here change over time? It’s more for a while and less for a while. The same is true for electricity in the process of flowing. The magnitude (amplitude) of alternating current is constantly changing, while the magnitude of direct current (such as dry batteries) is unchanged.

In electronic technology majors, electricity with varying amplitudes is generally called alternating current, and the signals we often mention (such as sound signals, image signals, temperature signals, etc.) are alternating current. The electricity whose amplitude and direction do not change is called direct current, and its purpose is to provide energy (ie, power supply) for the circuit. This kind of current is used in the mini car freezer .