Thyristors are four-layer semiconductor switches with alternating layers of P- and N-type materials. While all thyristors share the same basic structure, the details of their implementation and packaging can be modified to meet the needs of specific applications. This FAQ reviews basic phase control thyristor (PCT) operation, then looks at the use of bidirectional controlled […]
What’s the difference between an IGBT and an IGCT?
IGBTs and IGCTs are four-layer devices that don’t look that different at first glance. But, when you ‘look under the hood’, you find that an insulated gate bipolar transistor (IGBT) and an integrated (sometimes called ‘insulated’) gate commutated thyristor (IGCT) aren’t that similar. A bipolar transistor forms the basis of an IGBT, while an IGCT […]
How does a silicon controlled rectifier work?
A silicon controlled rectifier (SCR) is a four-layer power semiconductor device. The term ‘silicon controlled rectifier’ was coined by General Electric when SCRs were first introduced in 1957. Like rectifiers, SCRs are unidirectional devices. Today, SCRs are recognized as a type of thyristor. Other types of thyristors, such as triacs, are inherently bidirectional. This FAQ […]
How does the PICMG IoT.1 specification for smart IoT sensors work?
The PCI Industrial Computer Manufacturer’s Group (PICMG) is developing a series of specifications to enable plug-and-play interoperability of smart sensors and effectors. The effort includes the large installed base of legacy non-IoT (not IP-enabled) devices and newer IoT-enabled smart sensors. The PICMG program includes development of a family of three IoT specifications. PICMG IoT.1 is […]
What’s the difference between 2-, 3-, & 4-wire RDT sensing?
The difference is measurement accuracy. Using 2-wire resistance temperature detector (RTD) sensing provides good accuracy (maybe), the accuracy of 3-wire sensing is better, and 4-wire sensing provides the best accuracy. In addition, there’s the option of using Wheatstone bridge topologies to improve the performance of 2- and 3-wire RDTs. This FAQ begins with a review […]
What are emerging sensor technologies for Agriculture 4.0?
Agriculture 4.0 is emerging and requires an expended sensor suite. Agriculture 4.0 refers to systems that employ drones, robotics, the Internet of Things (IoT), vertical farms, artificial intelligence (AI), renewable energy, and advanced sensor methodologies. Agriculture 4.0 is similar to Industry 4.0 in some ways: Where Industry 4.0 is designed to support automation and mass […]
How does current sensing work?
Current sensing and measurement are important in applications such as power conversion, battery charging, and industrial processes. Different current sensing technologies are used, depending on whether the measurement is for alternating current (AC) or direct current (DC) and how much current needs to be measured. This FAQ reviews Hall effect, and induction sensing and resistive […]
What are alternatives to Li-ion batteries?
There are many alternatives to Li-ion batteries, including fuel cells, various types of supercapacitors, redox flow batteries, novel Li-based chemistries such as lithium-sulfur (LiS), and more. This FAQ focuses on alternative non-lithium rechargeable battery chemistries, including calcium-ion (Ca-ion), magnesium-ion (Mg-ion), sodium-ion (Na-ion), zinc-ion (Zn-ion), iron-air (Fe-air), and sodium-sulfur (NaS) that can be more readily integrated…
What is the controller area network (CAN) bus?
The controller area network (CAN) bus was developed to support the networking of large numbers of electronic control units (ECUs) in automobiles. CAN is implemented using unshielded twisted pair (UTP) cabling, designed for reliability in electromagnetically noisy environments. CAN has evolved significantly since it was first introduced in 1986, along with early ECUs. Today, there […]
What is the onboard diagnostics system, OBDII?
OBDII is the second-generation onboard diagnostic (OBD) interface. The first generation of OBD coincided with the advent of onboard computers in vehicles. Initial OBD systems were intended to provide technicians with information on the status of various vehicle systems, with an indicator light on the dash to alert drivers of a malfunction. OBDII includes more […]