In 1831, Faraday discovered that there is a relationship between electricity in motion and magnetic fields. This phenomenon is known as Faraday's electromagnetic induction. He utilized electromagnetic induction to create the prototype of the first electric motor, which later evolved into the modern coil-based motor.

The conversion of energy when an electric current flows through an object (converting electrical energy into kinetic energy and thermal energy) was formulated by Joule. He stated that "heat is a form of energy." Through experiments, Joule established the relationship between the flow of electric current and the resulting temperature change in an object, giving rise to Joule's Law. This law has proven immensely useful in modern applications, aiding in the calculation of efficiency and lifespan of devices.

法拉第在1831年發現電在流動的過程中會與磁場之間產生關係，這個現象被稱為法拉第電磁感應，並利用電磁感應發明出了第一個電動機原型，後來漸漸演變成現在的線圈式馬達。

在電流通過物體時所產生的能量轉換（電能轉換為動能以及熱能），是由焦耳提出的：「熱量是一種能量。」透過實驗找到電流流動對物體產生的溫度變化關係，而提出焦耳定律。對於現代設備在計算使用效率以及使用壽命計算，有非常大的幫助。