MEMRISTOR
A TRANSITION FROM ‘ELECTRONICS’ TO ‘IONICS’!!
FOURTH FUNDAMENTAL CIRCUIT ELEMENT
‘NATURE LOVES SYMMETRY’, this theory led scientist Louis Victor De Broglie to predict the existence of matter waves. Probably the world of Quantum mechanics wouldn’t be what it is today without De Broglie’s contribution.
Believing this same symmetric behavior of nature, professor Leon Chua predicted the existence of one more fundamental circuit element which he named as ‘MEMRISTOR’ (portmanteau of memory resistor). Resistance(R), Capacitance(C) and Inductance(L) gives relationship between V-I (Voltage- Current), V-Q (Voltage and Charge) AND Φ-I (Magnetic Flux and Electric current) respectively. Φ-V AND Q-I share a parent-child relationship as the latter is the time derivative of former in both the pairs. The only left out permutation was Φ-Q. Leon Chua gave relationship between these two and named it as Memristance (dΦ/dQ). Thus the missing piece of circuit family to achieve symmetry was found!!
RESISTANCE AND MEMRISTANCE
Unit of Memristance(M) is same as Resistance, Ohms(Ω). Expressions of R and M also look almost similar but practically they’re not same. Resistor is just a current limiting device but Memristor has a unique ability to remember the amount of charges flowing through it. Hence, it can retain its previous state when it loses power.
Let’s have a simple analogy to understand this. Imagine a normal pipe which allows the flow of water and is of fixed diameter and another special type of pipe which also allows water flow but can change its diameter based on the amount of water that’s being flown through it. So even when the flow of water stops, you can check the diameter of pipe and estimate what was the amount of water that was flowing just before water-inlet stopped.
Now compare water with charges, pressure at which water is pumped to electric potential applied. So, the normal pipe of fixed diameter becomes Resistor and the special “Water-Flow dependent” pipe is the “Charge-Dependent Memristor”. So it is clear that resistance of Memristor varies as a function of Magnetic flux and Current.
WHAT ELSE CAN A MEMRISTOR DO?
Memristor is creating buzz across the globe due to its unique and amazing applications which includes production of non-volatile memory storage devices, booting free computers, programmable logic & signal processing, analogic filters, Remote sensing & low-power applications. Memristors are an efficient solution for miniaturization of circuits as one memristor can perform function of 100’s of transistors.
MEMRISTOR AND AI
Another major field that the Memristor can impact is Artificial Intelligence, Neural Networks in particular. It’s being predicted that Memristor can work as a key element in VLSI implementation of neural networks which will boost the neuromorphic computing industry.
Memistor can be used to accurately emulate a key part of human brain for memory and Learning-Synapse. Memristor based processors can be 10-100 times more efficient the presently available GPUs.
THE FUTURE
Memristor which has all these useful applications is not yet commercially available since its path isn’t very smooth. Memristor is still under research phase and has no perfect design standards yet. Researches are going on in HP labs to produce solid state working Memristor. Memristor is being fabricated using Titanium since compatibility of silicon with properties of Memristor isn’t convincing yet. But if this Memristor does become commercial and successful, IONs based Memristor will be a future replacement to electrons based transistor. this may put an end to ‘ELECTRONICS’ and start a new era of ‘IONICS’.
BIBLIOGRAPHY:
1. Chua,l.O ‘Memristor-the missing circuit element’,IEEE Trans. Circuit theory 18
2. Soell,Christopher ‘Memristor based multilevel memories’,Wiley online library
Name : Shashank N
Email : nshashank7@gmail.com
College : Ramaiah Institute Of Technology
Branch : Electronics and Communication Engineering
Place : Bengaluru