Memristor is proposed as the fourth fundamental circuit element along with resistor, inductor and capacitor. It relates magnetic flux and charge, and its memristance can be switched to different states, giving it memory properties. Physically, a memristor can be analogous to a pipe that changes diameter based on direction of water flow, retaining its size when flow stops. Its ability to store information qualifies it as a fundamental circuit element, and it has applications as switches, non-volatile memory and more compact logic circuits.

1. Memristor symbol
By- Sanjay Soni
(2012 2055)

2. Known Three fundamental passive circuit elements:
Resistor, Inductor, Capacitor.

3. Does a fourth fundamental element exist?
v
i
q
φ
Resistor
dv=Rdi
Capacitor
dq=Cdv
Inductor
dΦ =Ldi
Memristor
dΦ =Mdq
Leon Chua
proposed the
existence of
memristor in 1971
In 2008 a team
lead by
Stanley
Williams
created the first
memristor

4. What is a MEMRISTOR
Memristor is really aMEMory ResISTOR
Memristor can be defined as a two
terminal device which shows the
relation between magnetic flux
and charge
memristor symbol

5. Memristor Theory
Or
Or

6. Memristor and Resistor
• The way resistor has resistance , memristor has
memristance.
• Same unit –ohm.
• Memristance can be switched to different states.
• Memristor has non linear v-i plot.

7. Physical analogy for a memristor
• Resistor is analogous to a pipe of fixed diameter
through which water is flowing
• Water(charge q), input pressure(voltage v), rate of flow
of water(current i).
• Resitance depends on diameter.
• Memristor is analogous to a special kind of pipe that
expands or shrinks when water flows through it.
• The pipe is directive in nature.
• If water pressure is turned off, pipe will retain its most
recent diameter, until water is turned back on.

8. Physical analogy for a memristor
Memristor Pipe
Charge Water
Conductance Cross sectional area
Potential Pressure
When water flows
in one direction
the diameter
increases
(resistance
decreases)
When water flows in
opposite direction
the diameter
decreases (resistance
increases)

9. Why memristor is a fundamental element?
• Can not be duplicated by R,C,L.
• Peculiar behaviour- carries memory of past.
• Duplication requires alot of transistors and capacitors.

10. V-I characteristics
• Resistor-energy
dissipated
• Capacitor-store
energy in electric field
• Inductor-store
energy
in magnetic field
• MEMRISTOR
– Store Information

11. Construction of TiO2 memristor
TiO2-x TiO2Pt
Equivalent circuit
Initially there are two layers, one
slightly depleted of Oxygen atoms,
other non-depleted layer.
The depleted layer has much
lower resistance than the non-
depleted layer.

12. Working of TiO2 memristor
Tio2-x
Tio2
Ron
Roff

13. Working as a switch
Off state (high resistance) On state (low resistance)
0 1
Positive direction-close the switch.
Negative direction-open the switch.

15. Benefits
Reliability when power is interrupted.
Great data density.
Less expensive.
By changing current, behaviour can be changed.
Do not consume power when idle.
 A typical processor chip in a laptop contains over a billion transistors. In
which transistors are 1000 times smaller than the diameter of a human
hair. So the circuits by memristors will be more compact.
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16. Future
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17. Applications
• As a switch.
• As a non volatile memory.
• Booting free computers.
• Can perform logic operations.
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18. Nonvolatile memoriesNonvolatile memories
The resistance-saving property makes memristors very appealing for use
in computer memory & freezing property prevents unintentional loss of
memory due to a power failure.

19. Conclusion
• No combination of R,L,C circuit could duplicate the
memristance.
• It takes a lot of transistors and capacitors to do the
job of a single memristor.
• So the memristor qualifies as a fundamental circuit
element.
• May replace transistors in ICs and has the potential
to open door to a brand new type of electronics.

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