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Friday, November 23, 2018

Accelerometers in Electronics

An accelerometer is a device that measures non-gravitational accelerations. These are accelerations produced by mechanically accelerating the accelerometer via its casing. Accelerometers can be used to measure vehicle acceleration.

Accelerometers can be used to measure vibration on cars, machines, buildings, process control systems and safety installations. They can also be used to measure seismic activity, inclination, machine vibration, dynamic distance and speed with or without the influence of gravity. - Accelerometer Wikipedia

Accelerometers in Electronics

MMA7260Q is a 3-axis accelerometer  from Freescale Semiconductor. This accelerometer can be used with an extension Library Mma7260q which simplifies some initialization values and tilt detection.

ADXL105 Lower-Noise Wider-Bandwidth Accelerometer - The ADXL105, a near-ideal kind of vibration sensor, eliminates significant problems with existing vibration sensors, such as piezoelectric and bulk capacitive sensors. Primary benefits derive from much lower cost, stable sensitivity as a function of frequency and temperature, ruggedness, and ease of use. Besides machine health and condition monitoring, it is particularly well suited for noise and vibration cancellation applications.

A beginner's guide to accelerometers - By measuring the amount of static acceleration due to gravity, you can find out the angle the device is tilted at with respect to the earth. By sensing the amount of dynamic acceleration, you can analyze the way the device is moving.

Society of Robots' tilt to servo control app - How does it work? Inside an accelerator MEMS device are tiny micro-structures that bend due to momentum and gravity. When it experiences any form of acceleration, these tiny structures bend by an equivelent amount which can be electrically detected

David T.'s motor balancing experiments - Using an oscilloscope to measure AC vibration signals generated by an accelerometer (from Dimension Engineering).

Circuit Builder with Oscilloscope - Physlets

Simulates AC and DC circuits. Created by by Toon Van Hoecke at the Universiteit Gent. Try out small circuits and see response in Meters and Scope. Using the Java Applet Power.

Install the latest Java jre and use the IE browser. In Control Panel Java-Security add a site exception webphysics.davidson.edu. Then you can see the simulations. (2017 win 10 )

Physlets, Physics Applets,

Physlets are simple.  The graphics are simple; each Physlet is designed to deal with only one facet of physical phenomena, and does not incorporate very much in the way of data analysis.  This keeps Physlets relatively small—easing downloading problems over slow network connections—and removes details that could be more distracting than helpful.

Circuit Builder with Oscilloscope - Physlets

Circuitbuilder simulates AC and DC circuits.  It was written by by Toon Van Hoecke at the Universiteit Gent.  Circuit Builder can be used in interactive mode (see above) or it can be scripted using JavaScript (see the demo pages). In order for scripting to work, Circuit Builder requires a Java 1.1 capable browser with JavaScript to Java scripting capability.

Friday, November 16, 2018

Transistor Beta and Vce Tester

This was a Beta Hfe and Vce Measuring Instrument used in Incoming Inspection of Power Transistors made by me 16 years back.

Transistor Beta Tester

Custom Built Test Instruments

I designed and built many custom "engineered" Test Instruments. They were not prefect, as only one or two were fabricated. That means it will be costly to produce such instruments. It is just like tooling, you have to make some numbers to recover costs, or price it very high to compensate for the wastages and iterations.

When making custom equipment, you have to have an extended service agreement like 5 years. Also request a minimum order of at least 5. Make your R&D and Inventory Modular. That way it is profitable and some money available for reinvestment on instruments and Equipment for calibration and quality.