Free Republic

I've built power supplies using full wave rectifiers in the past, and a couple circuits with single diode half wave rectification for non-critical supplies, but in all cases the power requirements were low and the diodes I had on hand several times overrated for the current and voltage / power involved.This time though, I want to add a half power function to a 1500 watt 120 volt quartz heater. (Over-simplification - see below comments. But ~half of the 1500 watts is the design target.)*So... I know a diode in series with the quartz element and no power supply capacitor** will...

A team of researchers at the Israel Institute of Technology has developed a new capacitor with a metal-insulator-semiconductor (MIS) diode structure that is tunable by illumination. The capacitor, which features embedded metal nanoparticles, is similar to a metal-insulator-metal (MIM) diode, except that the capacitance of the new device depends on illumination and exhibits a strong frequency dispersion, allowing for a high degree of tunability. This new capacitor has the potential to enhance wireless capability for information processing, sensing and telecommunications. The researchers report their findings this week in the Journal of Applied Physics. "We have developed a capacitor with the...

The 2014 Nobel Prize in Physics goes to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for work on blue light emitting diodes (LEDs). Discussed by Tom Foxon and Laurence Eaves.

Researchers from the US and Russia have shown how it is possible to measure the diode properties of a single molecule and how the orientation of the molecule between two electrodes can be controlled. The findings are a significant advance in the expanding field of molecular electronics, which seeks to construct electronic circuits from molecular-scale components, opening the prospect of a new generation of devices that are immensely powerful and efficient yet tiny.Diodes act as electronic 'check valves' in a circuit, permitting current to flow in one direction only through a process known as rectification. In a molecular circuit, single molecules acting...

Northrop Grumman has demonstrated exemplary performance capability of a laser chain, the first major building block of a solid state demonstrator laser designed to reach a power level of 100kW. The Joint High-Powered Solid State Laser (JHPSSL) Phase 3 program exceeded all target requirements of its second major demonstration milestone, including excellent beam quality. The JHPSSL system is designed to accelerate solid-state laser technology for military uses, including force protection and precision strike missions for air-, sea-, and ground-based platforms. "Northrop Grumman's JHPSSL will demonstrate the laser technology for the next generation of protection for the nation's warfighters on the...

COLUMBUS, Ohio ? Engineers have designed a new diode that transmits more electricity than any other device of its kind, and the inspiration for it came from technology that is 40 years old. Unlike other diodes in its class, called tunnel diodes, the new diode is compatible with silicon, so manufacturers could easily build it into mainstream electronic devices such as cell phones and computers. Industry has long sought to marry tunnel diodes with conventional electronics as a means to simplify increasingly complex circuits, explained Paul R. Berger, professor of electrical engineering and physics at Ohio State. "Computer chips now...