Friday, September 16, 2011

WEMS - EMI filters and Electronic Manufacturing

ISO 9001-2000 Certified Manufacturer of EMI filters and electronic and electromechanical systems.

WEMS - EMI filters and Electronic Manufacturing

"EMI / RFI Filter Division designs and manufactures high reliability input, output, powerline and signal line filters intended for military, aerospace, and high end industrial applications."WEMS - EMI filters and Electronic Manufacturing
Contract Manufacturing facilities of Wems Include -
  • Mechanical and Electronic Engineering
  • PCB Design & Assembly
  • Thru-hole Board Assembly
  • Surface Mount Assembly
  • Inspection & Testing to Aerospace, Military and Medical Standards
Box Build Specialists WEMS Manufacturing facilities offer total vertical integration.

Contract Manufacturing Division encompasses a wide variety of skills and technologies, including high voltage, high current, hydrolics, pneumatics and complete system assembly.

WEMS Electronics
4650 West Rosecrans Ave. Hawthorne, CA 90250

Thursday, September 15, 2011

Austin Circuit Design - Fabrication and Assembly

Austin Circuit Design provides printed circuit board design, fabrication, and assembly services.

AAustin Circuit Design - Fabrication and Assembly
Austin Circuit Design - Fabrication and Assembly

"Circuit Design Consultants, Austin Circuit Design's predecessor, was originally founded in 1985 by Greg Ochoa to fill an immediate need for quick-turn design, fabrication and assembly of prototype printed circuit boards."

Fabrication technologies include: flex, rigid-flex, controlled and mixed dielectrics, blind and buried vias, tented vias, and controlled impedance.

Their assembly partners offer both leaded and lead-free assembly and through-hole, surface mount, and mixed technology, single- or double-sided as required. BGA X-Ray and functional text are available.

Process Control Instrumentation - McShane

New serial interface RS-422 improved upon RS-232 serial communications which was Noise prone. RS-422 uses two signal lines.

RS-485 enhances RS-422 with an ability to connect upto 32 devices. Now we have Industrial Interface methods like Zigbee, Ethernet, Modbus etc.

RS-485 Serial Interface - McShane, Inc.

Temperature Controller for DC Load and TEC

Temperature Controller for DC Load and TEC

Model 5C7-582 or Model 5C7-583 temperature controllers provide automatic biphase heating and cooling control for Thermoelectric (Peltier effect, or TEC) modules.

More about the Company

Founded by Philip Johnson in 1964, McShane, Inc. supplies process control equipment, OEM devices, and industry services from our location south of Cleveland, Ohio.

They also provide services like Leading Edge Custom Built Designs, Prototyping and Manufacturing.

McShane, Inc.
3633 Trails End Dr., Medina, Ohio, 44256-8770, United States.

Friday, September 09, 2011

BOWest - Electrical and Project Engineering

BOWest is an Electrical and Project Engineering Consultancy within the mining, mineral processing and power generation industries.

Their Enginnering Service includes technical support for design, construction, commissioning, optimization and troubleshooting Medium and Large Electrical Systems, Plants and Machines.

BOWest - Electrical and Project Engineering

The Principal Engineer is Trevor A Bowland - BSc BA CEng MIEE

BOWest - Electrical and Project Engineering

Technical reference library in electrical engineering, published by BOWest Pty Ltd, Perth, Western Australia.

Electrical Engineering Reference - BOWest

The library does not include diagrams, it has the Definitions and Formulae for most or even nearly all that you will need in an Engineering Project. They have Theorems and Formulae for Electrical Circuits, Systems and Machines.

BOWest Pty Ltd
PO Box 330, Quinns Rocks WA 6030, Australia

Sunday, September 04, 2011

BD139 and BD140 Complementary transistor

BD139 and BD140 Complementary transistor

This pair is my favorite when driving small solenoids or motors. SOT-32 12 Watts..

BD139 - NPN, 80V and 1.5A, 40 beta min.
BD140 - PNP, 80V and 1.5A, 40 beta min.

This means any small solenoid, relay or DC motor can be controlled with this. I would use it upto 24V DC and max of 1A for applications of full on and full off.

In applications like a regulator or variable motor control, you have to keep in mind the current thru and voltage across the transistor which results in power dissipation. Let us say it is driving 0.5A thru a motor in speed control and the Voltage across is 30V then the dissipation could be 30 x 0.5 = 15 Watts.

That is the reason we use switched regulators or switched controllers. So if we chop the DC and do PWM you have only the Switching losses and also a bit of DC loss. Switched controllers are also green, they save power for the same work done, but generate EMI-RFI and care is required in sensitive uV circuits. The transistors for switching are also special as they have to be fast with less capacitance, hence the mosfets are preferred in those applications. - ananth (san)

Thursday, September 01, 2011

Digital Electronic Stethoscopes

The Heart, Liver and Kidney form a Vital Organ Tripod, on which rests the most Important Organ... Think about it......You are Thinking with it. Rack your Grey Matter with your copy of the Gray's Anatomy; to figure this Puzzle within.Digital Electronic Stethoscopes

Any of these three Legs, of this Tripod, Can be affected by wrong eating and living habits. After a certain age, you have to only Eat what you can burn, The rest is Poison. An electrician knows, If an Equipment is rated for for 12-Volts 3-Amps; He has to use within its Limits. An Electronics Engineer knows that he should never go near the "Absolute Maximum ratings".

Study more about the Vital Organ called Heart, by building an Electronic Stethoscope. See the Block Diagram (SBD) - Digital Stethoscope - TI.com. The sounds are very faint and a low frequency. It is a Bionic Challenge to acquire and amplify these small signals. Learn more about these concepts here ...

The SS30L Electronic Stethoscope will allow you to record and listen to heart sounds and Korotkoff sounds.

Here is a another Semiconductor Application from Maxim-IC Digital Stethoscope.

More Reading -

Mass Spectrometry and Portable Microbe Detector

Human Beings are helped or hampered by many types of Microbes. From the Sub-Microbe virus to animal like Bacterium and plant like Fungi.

An Affordable Portable Electronic Microbe Detector using Mass Spectrometry; may be very useful for Small HealthCare Centers and Homes. If a Person Breathes into an adapter in the instrument, it should show a simple analysis of the Air Microbe Levels. It can also be used for CleanRoom Air Purity Indication.

This is just an idea for an urgent need, this may prevent spread of flu to escalate into an epidemic; due to early detection of microbe, at the root, in every home.

Here are some Mass Spectrometry Resources that students can study and attempt to research to Develop a cost-effective consumer flu-detection device.