PC stands for "Personal Computer". An analog computer is one that uses vaccuum tubes and magnetic tape for its internal memory, processing, and storage components. A Digital Computer is one that uses transistors for it's internal memory, processing, and storage components. The term digital is in reference to the term "digit", which refers to a single character in a numbering system. Because the charge in a transistor is either on or off, it is read as either a "1" or a "0", hence making it "digital". This incorporation of transistors into their design is what makes the modern Personal Computer (PC) a Digital Computer. The original computers, such as ENIAC and early IBM Mainframe computers, were analog computers. These computers were huge, requiring entire rooms full of wiring and tubes to contain them. It was the advent of the transistor that allowed the size of computers to become the small miniature versions we have in our homes and workplaces today. When Personal Computers first arrived, they were also referred to as "micro computers". You may be interested to know that the first PC's did not have graphic displays and the mouse had not been invented yet. The output was simply an array of display lights on a panel, or text displayed on a screen, often in code. The first microcomputers were manufactured in the early to mid '70's and included Atari's, Comodore's, Tandy, and others. The Apple I Computer, designed by Steve Wozniak and Steve Jobs, arrived in 1976, and their company was called Apple Computers. The IBM PC was introduced in August of 1981 and it was IBM who first coined the term "Personal Computer" or "PC". It is highly unlikely that you will ever encounter an analog computer except perhaps in a museum, as all personal computers are digital computers.