delabs (Page 2)

delabs is a web-service for product design and development.

This is a Digital Panel Meter based on ICL7107. This was the workhorse Digital Readout chip before Low power uC designs were developed. Even now it is the easiest way an analog parameter can be displayed in an instrument.

Instrumentation and Measurement Circuits

3-1/2 Display is just enough resolution for recording process data or troubleshooting equipment. With 4-1/2 you notice the problems of thermoelectric EMF of probes and connectors. That is one reason gold plating is used another being low contact resistance. In 4 1/2 the reading can change due to contact resistance too, if the input impedance of the analog signal conditioning is low or the protection diodes, RC filter caps are leaky.

ICL7107 DPM Digital Panel Meter

When you measure an analog parameter from a sensor; you attenuate or amplify it, to scale to the A/D converter range. You also need to protect or isolate the analog front end from high energy mis-connections, which will happen during field use. The operator should not get injured from any high energy leakage while measuring.

Resolution is the finest detail you can enumerate in a parameter or object. You can say the crowd was 3000 or 4000 people. Here 1000 is the resolution, finer data does not matter here. You would also hear things like, there were 80 to 90 boys in that classroom. 10 is the resolution there.

Accuracy is how precise a statement or number is. If there was 85 boys in that class, the above statement is accurate. If there was 65 boys, the measuring method or process needs calibration or examination.

In this circuit, the plastic caps should be of very low leakage. Multilayer plastic caps are good for instrumentation.

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.

I once worked in Tek for a very short period. I got to experience the 2235 and 2465 analog scopes and their controls. The 2465 was a 400 MHz Digitally Controlled Analog Scope.

I also used the Plugin Scopes and Calibration systems that were Tek Culture and Tech contribution to the Instrumentation world, it probably evolved into VXI-PXI as uC systems took over.

delabs designs – The code has been moved from Google Code Hosting to github – delabs-dapj

delabs Web Widget and Application Interface Usability Experiments 2003-2008

I also had a chance to look at DSO/Logic Analyzers and the just developed TDS Series. The older tek analog scopes made me understand about usability and panel layouts. Many controls are inevitable in a Analog Scope with Electromechanical Interface.

In a Digital World that can be largely changed using the Monitor and Trackballs. The older BlackBerry phones are also good study for usability before Touch Screens came.

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This is a Regulated 0-30 V DC Power Supply manufactured by me in small numbers, 0-30V 5A and 5V -5A. It had a Switching Preregulator. This keeps the Vce across Transistor Bank at the Back of Instrument, at the lowest possible level, in order to keep them Cool. When Vce and Ic both are more in a Power transistor it will get heated more, then the efficiency of power supply is low.

Power Supplies Section – delabs

Variable Regulated Power Supply

The Output had both Constant Current Control and Constant Voltage Control. The CC control is also a Short circuit protection. The Output was protected from outside voltages damaging output circuits even when equipment is switched off. The back panel is a finned anodized black aluminum heat sink with many transistors.

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Mentor Graphics is a technology leader in electronic design automation (EDA), providing software and hardware design solutions that enable companies to develop better electronic products faster and more cost-effectively.

The company offers innovative products and solutions that help engineers overcome the design challenges they face in the increasingly complex worlds of board and chip design.

EZwave can analyze time or frequency domain waveform of any type: analog, digital, eye diagram, smith chart, polar or complex chart, and histogram. ”

Mentor Graphics – EDA Technology

“The EZwave Joint Waveform DataBase (JWDB) is a high-performance waveform database for manipulating huge waveform databases from leading simulators, loading gigabytes of data in seconds.

 LP Viewer

LP Viewer

“View Physical Component and Land Pattern superimposed for visual accuracy. You can turn layers on/off, print datasheets, see component dimensions, land pattern dimensions, calculator setting, global settings, Toe, Heel and Side statistical data.”

Below is a Electrical Control Panel, It has a Strip Chart Recorder which is electro-mechanical, It has a PLC Inside. A handheld PLC Programming unit. The computer is showing the Ladder Logic Program. PLC is based on a embedded uC. The DIN Controllers are Analog + Digital circuits. So you see it is a Electrical Control Panel with Electronics and the PLC Ladder Logic means, Software too.

Process Control Application Notes

This is a PID Controller based Control Panel using a PLC from GE Fanuc Automation. The Computer is a 386 40MHz with 40MB HDD.

PID Controller PLC

Electrical Control Panel Wiring

Control panes have many DIN Instruments like Indicators, Controllers and Recorders. They also have in the back end contacters, drives and circuit breakers with orderly wiring and cable management.

Many may already know about these EE Educational pages with Circuits of J. B. Calvert.  These pages are valuable as they are like a summation of Important and Practical Sections in many EE Subjects. If you want to master the basics of EE, these pages will propel you in the right direction.A Welath of Information is at the site – Dr James B. Calvert Associate Professor Emeritus of Engineering, University of Denver and Registered Professional Engineer, State of Colorado. An EE-Encyclopedia Almost.

Engineering and Technology – James B. Calvert
“An extensive series of pages based on experiments that can be done in the personal or home laboratory. The emphasis is on enjoyment and intellectual pleasure, but there is much practical matter as well.”

Electronics Index – Includes vacuum tubes and cathode-ray tubes, with many experiments for the home laboratory. Nixie clocks too.

The Electronics Index of J. B. Calvert

The Atmel AVR microprocessors are very similar functionally to the PIC microprocessors, with the same range in size from 8-bit, 8-pin PDIP to 32-bit processors with 100 pins, and similar features.
Atmel AVR 8-Bit Microcontrollers

The ATtiny13A will operate from a supply voltage as low as 1.8V (maximum clock speed 4 Mhz), and with a full 20 MHz clock speed at 4.5V and above. The current drain is much reduced at the lower supply voltages and clock frequencies.

A Magnetometer
It is easy to measure moderate magnetic fields using a Hall sensor, such as the Allegro A1302 linear Hall sensor, available from Jameco. A PIC12F675 can digitize the output of the sensor and display it on a serial LCD display, such as the Newhaven NHD-0216K3Z-FL-GBW 2 line x 16 digit display. This system is shown breadboarded in the figure at the right, measuring the field between the poles of a horseshoe magnet.