Voltages shift rapidly in modern electronics, as do other elements of the output such as amplitude and wavelength. Back in the day, engineers had to infer thresholds for their devices by measuring the results of voltage spikes indirectly, creating an environment in which precise calibration of oscillating changes could not yet be measured accurately. The advent of the triggered oscilloscope in 1946 revolutionized the ways engineers interfaced with, and diagnosed, their machinery.Today scopes are put to a wide variety of essential tasks, from measuring electrical signals in the brain through monitoring the networks at rock concerts. Along the way, the scopes have grown ever smaller and faster, supplanting vacuum tubes with transistors to create instant waveforms in millionths of a second. It came as no surprise, then, that the rise of personal computing also heralded a conversion from freestanding device into adjunct hardware for these clever machines.Tektronix, the company behind many of the key innovations of the last century, today offers scopes in a variety of forms, sensitivities and price ranges. One of the most popular options for true geeks is the xoscope, or oscope, which is designed expressly to work with that most democratic of operating systems: basic Linux. Used in tandem with a PC, this kind of scope can easily watch a network connection or a security line for unwanted fluctuations, creating security and instant feedback for the techs who install them.If you are in the market for a Tek oscope and want to save some money, it may be worth looking into online portals where hobbyists swap these products at significant discounts.