Electronics Engineering Magazine

Saturday, April 09, 2016

National Semiconductor

National Semiconductor was an American semiconductor manufacturer, that specialized in analog devices and subsystems, formerly headquartered in Santa Clara, California, USA. The products of National Semiconductor included power management circuits, display drivers, audio and operational amplifiers, communication interface products and data conversion solutions.

Wiki of National Semiconductor

National's key markets included wireless handsets, displays and a variety of broad electronics markets, including medical, automotive, industrial, and test and measurement applications.

On September 23, 2011, the company formally became part of Texas Instruments as the "Silicon Valley" division.

An Exquisite Evaluation Board from National Semiconductor

The LMH0356 Serial Digital Interface (SDI) reclocker is designed to recover a clean clock from a serial digital video signal which may be contaminated by jitter and to resynchronize the input video data to the recovered clean clock. The LMH0356 SDI reclocker accepts signals conforming to standards SMPTE 259M (C), SMPTE 292M, and SMPTE 424M.

Friday, April 08, 2016

Blind Dial Proportional Temperature Controller

This is a Low cost controller, Analog Dial Temperature Controller. It is also called Blind Controller. This essentially means Open Loop, just control the fuel or energy input to the system to regulate heat. This is not a Blind Controller that way, it only cannot display the temperature value, that could be another reason it is called blind.

Blind Dial Proportional Temperature Controller

Blind Temperature Controller

Dial cyclic timers were used to control heat, these were purely mechanical clockwork devices. They could regulate well, when the material flow (liquid) is constant and mains power is regulated. But when the job to be heated, varies in quantity, control temperature is close to ambient or when a precise control is required; closed loop controllers are used. Even a thermostat is like closed loop, as the bimetallic sensor is temperature dependent. But not good enough.

This controller is closed loop, precision controller, only the digital display of temperature is absent. Fine one deg variations may not be easy in this.

Blind Dial Proportional Temperature Controller

Blind Dial Proportional Temperature Controller

Wednesday, April 06, 2016

The MOSFET in Power Electronics

delabs Notes - In a Circuit Module, if all Power and Signal Polarities are reversed. All NPN to PNP, All N-Channel to P-Channel and Vice Versa. All Diodes and Caps too turned around. This Topsy Turvy or Mirror Design ought to work in Theory. It has worked for some circuits in practice too in my experience. ?

Some believe that N-Channel is more Robust than the P Type. In Bipolar Transistor NPN is more trusted for the final output stages. The NPN Transistor and N-Channel turn-on by a Positive control bias. It may be inappropriate to say this mosfet is NPN or PNP.

The MOSFET in Power Electronics

The traditional metal–oxide–semiconductor (MOS) structure is obtained by growing a layer of silicon dioxide (SiO2) on top of a silicon substrate and depositing a layer of metal or polycrystalline silicon (the latter is commonly used). As the silicon dioxide is a dielectric material, its structure is equivalent to a planar capacitor, with one of the electrodes replaced by a semiconductor.

If the MOSFET is an n-channel or nMOS FET, then the source and drain are "n+" regions and the body is a "p" region. If the MOSFET is a p-channel or pMOS FET, then the source and drain are "p+" regions and the body is a "n" region. The source is so named because it is the source of the charge carriers (electrons for n-channel, holes for p-channel) that flow through the channel; similarly, the drain is where the charge carriers leave the channel. MOSFET - Wikipedia

This application note discusses the breakdown voltage, on-resistance, transconductance, threshold voltage, diode forward voltage, power dissipation, dynamic characteristics, gate charge and dV/dt capability of the power MOSFET.
Application Note AN-1084 Power MOSFET Basics - IRF

A MOSFET is a transistor. It is a Metal Oxide Field Effect Transistor. Here are the symbols for FETs and MOSFETs: The MOSFET How the MOSFET works

The conductivity of the path from Source to drain is controlled by applying a voltage between the gate and the body of the semiconductor. N-channel enhancement MOSFET

See this simple circuit that explains everything
n-channel MOSFET switch - George Watson, Univ. of Delaware, 1996.