The calculator of today is an example of digital electronics. Digital electronics is different from analog. In digital electronics pulses of electricity are used. Continuously flowing electricity is analog. Information needed to make calculations uses binary code (pulses of high current stand for 1 and pulses of low current stand for 0).When you hit a calculator button it sends an electronic signal to the digital electronic circuits. The button completes the circuit when a switch that touches the metal contact pad is pushed. You can see the results on the screen of the calculator. The digital electronic circuits store numbers and do the calculations.