DIGITAL LOGIC DESIGN UNIT 1 EXAM
WITH 100% CORRECT ANSWERS {
GRADED A+}
Combinational Circuit - ✔✔A digital circuit whose output value depends solely
on the present combination of the circuit inputs' values. Ex: doorbell system
(button pressed, doorbell sounds)
Sequential Circuit - ✔✔The output value depends on the present and past input
values. Ex: toggle lamp, that stays on even after the button is released
Voltage - ✔✔Difference in electric potential between two points, tells us how
eager the charged particles on one side of a wire are to get to ground on the wire's
other side. Analog
Current - ✔✔Measure of the flow of charged particles. Indicates the rate that
particles are actually flowing.
Resistance - ✔✔Tendency of a wire to resist the flow of current.
,Ohm's Law... - ✔✔V=IR
Three parts of a switch? - ✔✔Source input which has a higher voltage than the
output so the current tries to flow from the source input through the switch to the
output. Output and Control input
Purpose of a switch - ✔✔The purpose of a switch is to block that current when
the control sets the switch "off" and to allow that current to flow when control sets
the switch "on"
Relays - ✔✔Electronically controlled switches: switches whose control input was
another voltage.
A relay has a control input that is a type of magnet which becomes magnetized
when the control has a positive voltage.
Vacuum tubes - ✔✔Relays relied on metal parts moving up and down which was
really slow. Vacuum tubes began to replace relays in computers. In a vacuum tube,
an extra terminal is added inside the bulb, separated by the vacuum from the
filament. If a positive voltage is applied at that terminal, then electrons can flow
from the filament to the extra terminal through the vacuum so this causes a
connection between the filament and the extra terminal
, Since vacuum tubes had no moving parts, they were much faster than relays but
consumed a lot of power, generated a lot of heat and failed frequently
Discrete Transistors - ✔✔Resulted in smaller and lower-power computers.
Solid-state (discrete) transistor uses a small piece of silicon "doped" with some
extra materials to create a switch
Integrated Circuits - ✔✔An IC (chip) packs tiny transistors on a piece of silicon.
Smaller transistors=less distance for electrons to travel=faster
CMOS Transistor - ✔✔Reread pages 40-42
NOT Gate has one input: if input is 0, ______ transistor will conduct - ✔✔pMOS
NOT Gate has one input: if input is 1, ______ transistor will conduct - ✔✔nMOS
Why do CMOS circuits consume less power - ✔✔because current never flows
from the power source to ground
Can build an OR gate using _____ - ✔✔two pMOS transistors and two nMOS
transistors
pMOS vs nMOS transistors? - ✔✔pMOS conducts when gate is one, nMOS
conducts when gate is 0.
WITH 100% CORRECT ANSWERS {
GRADED A+}
Combinational Circuit - ✔✔A digital circuit whose output value depends solely
on the present combination of the circuit inputs' values. Ex: doorbell system
(button pressed, doorbell sounds)
Sequential Circuit - ✔✔The output value depends on the present and past input
values. Ex: toggle lamp, that stays on even after the button is released
Voltage - ✔✔Difference in electric potential between two points, tells us how
eager the charged particles on one side of a wire are to get to ground on the wire's
other side. Analog
Current - ✔✔Measure of the flow of charged particles. Indicates the rate that
particles are actually flowing.
Resistance - ✔✔Tendency of a wire to resist the flow of current.
,Ohm's Law... - ✔✔V=IR
Three parts of a switch? - ✔✔Source input which has a higher voltage than the
output so the current tries to flow from the source input through the switch to the
output. Output and Control input
Purpose of a switch - ✔✔The purpose of a switch is to block that current when
the control sets the switch "off" and to allow that current to flow when control sets
the switch "on"
Relays - ✔✔Electronically controlled switches: switches whose control input was
another voltage.
A relay has a control input that is a type of magnet which becomes magnetized
when the control has a positive voltage.
Vacuum tubes - ✔✔Relays relied on metal parts moving up and down which was
really slow. Vacuum tubes began to replace relays in computers. In a vacuum tube,
an extra terminal is added inside the bulb, separated by the vacuum from the
filament. If a positive voltage is applied at that terminal, then electrons can flow
from the filament to the extra terminal through the vacuum so this causes a
connection between the filament and the extra terminal
, Since vacuum tubes had no moving parts, they were much faster than relays but
consumed a lot of power, generated a lot of heat and failed frequently
Discrete Transistors - ✔✔Resulted in smaller and lower-power computers.
Solid-state (discrete) transistor uses a small piece of silicon "doped" with some
extra materials to create a switch
Integrated Circuits - ✔✔An IC (chip) packs tiny transistors on a piece of silicon.
Smaller transistors=less distance for electrons to travel=faster
CMOS Transistor - ✔✔Reread pages 40-42
NOT Gate has one input: if input is 0, ______ transistor will conduct - ✔✔pMOS
NOT Gate has one input: if input is 1, ______ transistor will conduct - ✔✔nMOS
Why do CMOS circuits consume less power - ✔✔because current never flows
from the power source to ground
Can build an OR gate using _____ - ✔✔two pMOS transistors and two nMOS
transistors
pMOS vs nMOS transistors? - ✔✔pMOS conducts when gate is one, nMOS
conducts when gate is 0.
