Part 1 introduced some of the issues related to charging of electric vehicles. Part 2 continues with a look at the hardware (which also involves software, of course). Q: What about the electrical and physical connections? A: There are three connection situations, called “cases”: Case A has the charger connected to the AC mains, and […]
RF Switches, Part 2: Analog and MEMS switches
Part 1 of this FAQ looked at the venerable electromechanical RF switch – still widely used in some applications, where it is the only viable option – and use of PIN diodes as RF switches. This part looks at analog and MEMS-based switches. Q: What is an analog switch? A: It’s conceptually straightforward: in basic […]
RF switches, Part 1: Mechanical and PIN-diode switches
There’s a ubiquitous and increasing need to switch RF signals ranging into the tens of GHz; four basic switch technologies – electromechanical, PIN diode, analog, and MEMS – are available, each with different features and capabilities. The need to switch RF signals has been a necessary design function since the earliest days of “wireless.” This […]
Charging electric vehicles, Part 1: the numbers
It’s nice to envision that recharging an electric vehicle is as straightforward as filling up an internal combustion vehicle, but it’s not: there are multiple charging, power, and connector options as well as limitations. You’re driving your internal-combustion (IC) car, and the gauge indicates it’s time to get “gas” (of course, it’s actually gasoline). So […]
The electromagnetic rail aircraft launch system, Pt 2: Implementation and issues
Part 1 of this FAQ explored the basics of the EMALS “railgun” technology being implemented for launching aircraft from carriers; this part details the actual installation on a carrier. Q: What are the various subsystems the EMAL system? A: The overall design has six major functional blocks, (Figure 1). The Prime Power Interface, which is […]
The electromagnetic rail aircraft launch system, Pt 1: Objectives and principles
The traditional and battle-tested steam-powered catapult used to launch aircraft from carriers is being replaced by a powerful, electromagnetic-based, closed-loop linear-motor system — maybe. For over seven decades, the steam-powered catapult has been the standard mechanism for launching airplanes from the decks of aircraft carriers, with an associated cable-tensioned brake used for arresting them on […]
GaN power devices, Part 2: Application
Part 1 of this FAQ explored the basics of GaN switching transistors at the device and physics level. This part will look at driving and applying GaN devices. Q: What do I need to know to use a GaN device? A: There are three functional blocks associated with power switching: the power-device driver, the power […]
GaN power devices, Part 1: Principles
Power devices based on gallium nitride (GaN) are rapidly becoming a viable, higher-performance alternative to silicon MOSFETs due to their higher efficiency and other favorable attributes. In recent years, discrete power-switching and power-handling devices based on gallium nitride (GaN) material have become practical and available, and these devices are now found in many power supplies […]
Specialized diodes, Part 2: Varactor, Gunn, and PIN diodes
Part 1 of this FAQ reviewed the standard PN semiconductor diode, and looked at some specialized variations called the tunnel, Zener/avalanche, and Schottky diodes. Part 2 briefly explores the varactor, Gunn, and PIN diodes. Q: What about the varactor diode? A: The varactor diode (Figure 1), also called a voltage variable capacitor (VVC) or varicap […]
Specialized diodes, Part 1: Tunnel, Zener/Avalanche, and Schottky diodes
There are diode varieties which do much more than just block current flow in one direction and allow it in the other; some of these special diodes have favorable attributes while others are essential in modern electronics. Every electronic engineer is familiar with the diode: it’s a basic, widely used, two-terminal semiconductor device. The diode’s […]