What is a memristor and what does it do?

You’ve surely heard of the memristor, a key part in digital electronics that wasn’t implemented until a few years ago, although it was theorized decades ago to be the missing link in electronics. This part is a mix between a transistor and a resistor. And the uses it could have are interesting.

Basic electronic devices

Basic electronics is the study of electronic circuits that use only standard electronic components such as resistors, capacitors, batteries, diodes, and transistors. Such circuits are often called “low-tech” because they do not contain many high-tech components. But this field has a lot to offer because it can be useful when designing simple circuits. Even if you don’t plan to pursue basic electronics as a career, you may find this information useful for your personal projects or studying for school exams.


A resistor is a component that controls the flow of electricity. The amount of resistance is measured in Ω (ohms), with higher numbers meaning less resistance (aka more voltage). When electricity enters a resistor, one of the charges will be completely absorbed by the resistor and the rest of the charge will go its own way. The remaining charge is released as heat. The amount of heat released depends on the amount of resistance of the resistor. Therefore in circuits we often have to use resistors that are the correct size for the amount of heat produced.

Resistors are made from many different materials, but carbon is the most commonly used. Carbon can absorb electrical charge because it has a higher concentration of electrons than other materials. When electricity is directed across a carbon resistor, electrons in the carbon can absorb the charge, leaving behind heat. Electronic components can be made from carbon because it has a high concentration of electrons. A resistor is a component with atoms that can absorb electrons or allow them to flow through. If the number of electrons inside a component is greater than the number outside it, electrons will flow through the component. Electrical components are made of materials that can store electrons to control the flow of electricity. The most important component is the resistor.


A capacitor is a circuit component that can store electrical energy. This is useful because when electricity is stored in a capacitor, it does not need to flow quickly through a circuit. In fact, it can flow at a much slower rate, which is especially useful for filtering and amplification. Like resistors, capacitors are made from many different materials, but they are most commonly made from conductive materials. The two most commonly used materials for making capacitors are aluminum and plastic. However, capacitors are made of many other materials that are also conductive. The two most important factors when choosing a capacitor are the amount of capacitance it has and its capacitance at voltage.


A diode is a component that conducts electricity in one direction but blocks it in the other direction. In other words, a diode allows electricity to flow through it but blocks its path. Diodes are used in electronic circuits because they allow you to control the amount of electricity flowing through a circuit. They can be used to amplify electricity or block it completely. The two most common types of diodes are silicon and gallium arsenide (or “germanium”). Many electronic devices use silicon diodes to amplify or completely block electricity flowing through the circuit.


Electronic circuits need power. This power can come from batteries or an alternating current (AC) power source. There are many types of batteries used in electronic devices, but the most commonly used are alkaline, lithium, and nickel-cadmium. Alkaline batteries are the most commonly used battery type in small electronic devices. Lithium batteries are the most commonly used battery type in portable electronic devices such as laptops and smartphones. Nickel-cadmium batteries are the least used.

What is a memristor?

Leon Ong Chua, a professor of electrical engineering at the University of California at Berkeley, first recognized the possibility of such a non-volatile electronic memory device in 1971, calling it a memristor (IEEE Circuit Theory, “Memristor”).

Unlike other memories currently used in modern electronics, memristors are durable and remember their state even when the machine loses power. The memristor was discovered in 2008 by a group of scientists led by Stanley Williams at HP Research Laboratories. They found that metal oxide thin-film devices that switch between a conductive and less conductive state exhibit the behavior of Leon Chua’s memristors.

Since then much research has been done in this area. Very high density crossbar arrays including memristors (Nature Nanotechnology, 6-nm half-pitch and 2-nm critical size Memristor crossbar arrays) and multilayer stacking (120 billion cycles) have been recently realized. Thanks to this work, computer systems now frequently use memristors (memristors are extremely fast and reliable). RAM is used in computers to store data while the user is working; However, if the power is lost, the data will be lost. Flash memories, on the other hand, store information when there is no power, but they operate much slower. A memory that combines the speed and reliability of RAM would be the best of both worlds.

Memristors have several advantages that make them attractive to computer scientists. They require less power to operate, are faster than existing solid-state storage technologies, and are readily available. Unlike traditional transistors, which can be damaged by radiation, memristors are virtually radiation-proof. You can also create computers with memristors that turn on and off like a light switch.

Memristor production

Although memristors have variable resistance, their electrical resistance is set to constant. The voltage-dependent resistance of a memristor is specific to its electrical properties. Interestingly, memristors have a fairly simple structure consisting of a thin film of titanium dioxide between two metal electrodes. Memristors are created by placing metal electrodes side by side. The voltage-dependent resistance of memristors is what makes them remarkable. Scientists have discovered that metal oxides, chalcogenides, amorphous silicon, carbon and polymer-nanoparticle composites exhibit memorization behavior. They also demonstrated that protein-based nanodevices are memristors.

The researchers also demonstrated the ability to reversibly control the learning properties of memristors by optical means, namely light. The great interest aroused by memristor devices is also due to the fact that they imitate the memory and learning properties of biological synapses, that is, the value of the electrical resistance of the device depends on the history of the current passing through it.

Memristor properties

In light of the fact that memristors are expected to be incorporated into neuromorphic computing applications, it makes sense to design a new generation of ultrafast, low-power, memory-intensive AI devices. Because computers have separate memory and processing units, neural networks can operate with lower amounts of power than digital computers. Additionally, neurons serve as memory for the brain, making neural networks strong.

Scientists want to develop artificial nervous systems that physically resemble biological nervous systems to create neuromorphic devices. The human brain has approximately 10,000 synapses, just over 1,000 neurons, and requires a low-power, nanoscale synapse-like device to scale the neuromorphic circuit to human brain levels. Because memristors exhibit the same switching behavior as synapses in the human brain, they can be used in neuromorphic processors to simulate learning and computation in the human brain.

Synaptic competition and cooperation are believed to be critical to neuroscientists. It is now possible to create memory devices that mimic synapses in a solid-state system and implement these behaviors.