binary-base 2, represented by numbers 0 and 1, represents the concepts of true and false, on and off, light and dark, magnetized or not magnetized

bit- contraction of 'binary digit', can be either a 0 or a 1

transistors have 2 states, on and off, and are solid-state switches.  Solid-state means there are no moving parts, and can operate through billions of cycles without wearing out like a mechanical switch.  An example of a mechanical switch is a light switch.

byte- 8 bit number, such as 0101 1010

2 to the power of 8 = 2*2* 2*2* 2*2* 2*2 =256, is the number of possible decimal values from 0 through 255 (decimal, base 10)

The EBCDIC/ASCII code allows you to convert / encode /translate 'human readable characters' into 'machine (computer) readable' 8 bit binary values

example

letter 'S' is ASCII binary 1010011 or decimal 83

digit '6' is ASCII binary 0110000 or decimal 48

ref:  http://www.asciitable.com/