JoSS: Joy of Sharing Science No: 3

Joy of Sharing Science
(Image taken from Prof.
Guri Sohi, “Transistors
and Logic Gates”)
A NOT gate reverses the input by converting 0 into 1 and 1 into 0. When no voltage
is applied to the input wire, the P-type transistor will pull the output voltage up,
resulting in the output wire to have electricity flowing through itself and an output
of 1. However, when high voltage has an input of 1 applied to the “in wire,” the N-
type transistor will pull the voltage down; the current will be led to the source,
leaving the “out wire” without electricity. This causes the output to be 0. This basic
principle of connecting P-type and N-type transistors in a circuit is similarly used to
implement AND and XOR logic gates.
AND Gates:
AND is one of the Boolean operations. The AND gates accept two wires. If both
wires are “on” as electricity is flowing through them, they will be in true state
represented by 1. Then, two 1 will output 1.
(Image taken from Pamela Fox, “Logic gates”)
However, if both wires are “off” as no electricity is flowing, then they will represent
the false state as two 0s of input. Consequently, the output will also be 0 as seen in
the figure below.