Circuit analysis involves designing new circuits as emerging technologies become commonplace. And of course, integrating all the components of these new technologies requires circuit analysis. Here are ten exciting technologies used in current and up-and-coming circuits.
The touchscreens found on smartphones use a layer of capacitive material to hold an electrical charge; touching the screen changes the amount of charge at a specific point of contact. In resistive screens, the pressure from your finger causes conductive and resistive layers of circuitry to touch each other, changing the circuits’ resistance.
When you locate the capacitance or resistance changes with a coordinate system, you can have multiple fingers controlling the display of the smartphone.
Research in nanotechnology developed techniques to design and build electronic devices and mechanical structures with atomic-level control. With atomic-level control, you can synthesize materials with optimum resistance and material strength. With the circuit size reduced, the system speed increases, and it’s possible to operate devices within the terahertz (1012 Hz) range.
Nanotechnology offers a lot of promise in a variety of fields. It may reduce greenhouse gases, limit deforestation, decrease pollution, and allow cheap manufacturing. For the home, high-tech gadgets may identify deadly bacteria. On the medical front, small, inexpensive implantable sensors could monitor your health and provide semiautomated treatment.
One special category of nanotechnology is the use of carbon nanotubes hollow structures with walls formed by one-atom-thick sheets of carbon. The sheets are rolled at specific discrete angles to determine the nanotube properties, such as strength.
Carbon nanotubes have a wide range of potential applications such as:
Targeted medication: Coating porous plastic with carbon nanotubes can create implantable biocapsules that can detect problems in blood chemistry or deliver chemotherapy drugs directly to thermal cells.
Cleaning oil spills: When you add boron atoms to growing carbon nanotubes, the nanotubes become sponge-like, absorbing oil.
Creating new materials: Carbon nanotubes may be used to create new materials that change the surface shapes of aircraft wings when a voltage is applied. Carbon nanotubes can also fill voids found in conventional concrete, preventing water from entering the concrete and increasing the concrete’s lifetime.
Energy efficiency: You can recycle wasted heat as electricity by using thermocells that use nanotube electrodes.
Microelectromechanical systems (MEMS) devices are manufactured using similar microfabrication techniques as those used to build integrated circuits. MEMS can have moving components that allow the device to perform physical or analytical functions in addition to the electrical function.
In biomedical applications, MEMS can be used for retinal implants to treat blindness, neural implants for stimulation and recording from the central nervous system, and microneedles for painless vaccinations. Due to the short time scale under physiologically relevant conditions, MEMS can activate body systems by delivering an electrical stimulus, drugs, or both.
Supercapacitors (or supercaps) are energy storage devices with very high capacity and low internal resistance. The energy is stored in a double-layer electrolytic material, so supercaps are often called electrochemical double-layer capacitors (EDLC). Compared to conventional electrolytic capacitors, supercaps have high energy and power densities, as well as a longer lifetime.
Unlike the capacitor, resistor, and inductor, the hypothetical memristor can memorize the nonlinear resistance by controlling the charge or magnetic flux. Unlike conventional resistors, the direct current (DC) resistance of the memristor depends on the total charge that passes through the device in a given time interval. If you turn off the driving signal, the memristor’s resistance stays at that value until the signal is turned back on.
Because of the nonvolatile properties, the memristor could be used in high-density storage devices. Other possible applications for memristors include reprogrammable digital logic circuits and smart interconnects.
Superconducting digital electronics
Digital semiconductor devices have been shrinking in size for many decades. As you shrink these devices, heating becomes an important problem along with increasing delay times due to wire (trace) resistance.
Superconducting digital devices offer high speed and reduced power with high-density packaging and superconducting interconnects. Power consumption in high-frequency operation is three orders of magnitude less than the CMOS (complementary metal oxide semiconductor) logic, which is a type of circuitry that minimizes the amount of power used.
Wide bandgap semiconductors
Wide bandgap materials are semiconductors with bandgaps greater than 1 electron volt (eV). Wide bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) promise to revolutionize both optoelectronic and electronic devices.
New lasers and light emitting diodes (LEDs) are possible, including blue-green lasers, blue-green or white LEDs, solar-blind detectors, high-power solid-state switches and rectifiers, and high-power microwave transistors. Wide bandgap semiconductors might also be used in high-temperature electronics, especially in automotive, aerospace, and energy applications.
Flexible electronics covers a wide range of device and materials technologies that are built on flexible and conformal substrates (substrates that conform to the shape of a flexible surface so you can imprint electronic components). They provide opportunities to integrate a variety of components that are fluidic, mechanical, optical, and electronic.
Radio frequency identification (RFID) tagging has emerged as one of the building blocks of flexible electronics. Other technologies, including carbon nanotubes, nanowires, and other nanomaterials within semiconductors are being developed to tailor properties of cost, mobility, and scalability. Flexible electronics may have additional applications in healthcare, the automotive industry, human-machine interactivity, energy management and mobile devices, wireless systems, and electronics embedded in living and hostile environments.
Microelectronic chips that pair up with biological cells
By growing biological cells atop CMOS-based microelectrode arrays, researchers can study — and emulate — how information is processed in the brain.
By adopting integrated circuit (IC) or CMOS (complimentary metal oxide semiconductor) technology, you can address the connectivity of many transducers or electrodes by using automated electronics to look at an array of sensors or transducers; condition the signal quality at the electrode using dedicated circuitry such as filters and amplifiers; and reduce the system complexity, because many functions can be programmed through software and digital registers on the chip side.