Laboratory instrument to observe changes of electric signals on the screen.
Oscilloscope is a laboratory instrument to observe changes of electric signals on the screen. The operator of the oscilloscope uses a probe with pin at its end connected by shielded cable to the input of the device. The level of the signal (voltage) is divided in the probe (to avoid oscilloscope destruction) and then signal goes into the electronics inside.
In the classic oscilloscope signal cause deviation of the electron beam in the vacuum tube, what allows to see the shape of the signal on the phosphor layer of the vacuum tube.
In modern digital oscilloscope signal enters into analog to digital converter (ADC) then is processed by the processor or dedicated integrated gate array, then displayed on LCD screen.
While digital oscilloscope offers lot of interesting functions they introduce large delay of signal processing in opposition to analog oscilloscope, while the latter is less rich in features.