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Friday, May 03, 2019

Engineering Poetry and Heuristics

Knowledge comes in Handy at every part of your Life. Entertainment should be Edutainment. Here is a collection of comments and blurbs i wrote around 2012 - delabs

Verify Again and Again

After doing something, Verify, ask a friend to crosscheck, verify again.



Engineering Poetry and Heuristics

Wait there is more ...

Then ask somebody who does not like you so much, to check or test it and offer critical comments.

delabs design service - Circuit and product design


Differential Amplifier - Op-Amp Designs

A very simple one op-amp diff amp. This amplifies the difference between two inputs Vp and Vn the low impedance of this configuration is a drawback, but can be used in analog computing. Optimum VCC VDD can be +12/-12. AC signals common to Vp and Vn are canceled by this configuration.

Differential Amplifier - Op-Amp Circuits

Differential Amplifier - Op-Amp Designs

Use a capacitor like 10nF plastic from pin 2 to 3 or across R2 to make circuit stable. For AC applications use LF351 TLO71 as they have good slew rate and also are FET inputs. For AC applications use a capacitor (1uF) in series with Ri to block DC Components.

Buffer Unity Gain Amp - Op-Amp Designs

If output impedance of a point is a high value then connecting another circuit at that point will load it, resulting in malfunction or error. Buffers are used as interface between circuits.

Low impedance of an output means it can source/sink lot of current, when you need 2 opamps use LF353 or TL072 which are dual opamps.

Buffer Unity Gain Amp - dapj Tech Widgets

Buffer Unity Gain Amp - Op-Amp Designs

A non-inv FET input is the best buffer, for inverting buffer use high R values. Using very high R values like 2.2M or higher requires a glass epoxy PCB and guard rings around pin 2, 3 to prevent leakage currents on the PCB reaching the PINs.

Also moisture and dust has to be prevented by using RTV coating or Varnish. Use 78L05 and 79L05 for the dual supply required by this circuit.

Inverting Amp   -   Vout = -1 * Vin

Non-Inverting Amp   -   Vout = Vin

Vary the Millivolt Source by just hovering your Mouse pointer over the Two Buttons (Increment and Decrement). If you leave the mouse pointer on a button, the variation will pick up speed. Set a Value of your choice, positive or negative, you can set from -199.9mV to +199.9mV. Note the Output values on both the DVMs on the right (digital Volt Meter) in a Table. Repeat this for at-least 7 readings of both polarities. Jot the Formula below in your book and relate it to your table.

Saturday, April 06, 2019

Dual Differential Amp - Op-Amp Designs

The Input Impedance of this module is very high and is symmetric. This circuit can be used for strain gauges and for four wire measurements. If inputs are in mV use OP07. The merit is that it uses only 2 OpAmps yet has high differential Input Impedance.

Dual Differential Amp - Op-Amp Designs

Dual Differential Amp - Op-Amp Designs

The Outputs of Opamps are low impedance but still have limits they cannot drive more than a few mA of Current into the Load. If low ohmic value loads are to be applied use external transistors as amplifiers. If inputs Vn-Vp are floating, outputs may be random or oscillating, it is good to have a bias network of 10M resistors to a potential even zero or common, this enables some Vout when input floats.

Astable Multivibrator with 555

This is a demo of the popular 555 timer. you can try out the project on this page by a javascript simulation. Press the Red button below to turn on the circuit press it again to turn off. The 555 can source (LED2) or Sink (LED1) upto 200mA.  If you are starting with electronics, this is the first step. So do it now ! Do-It-Yourself.

Screenshot of Astable 555 Timer Flasher

It can even drive a small motor or lamp with diodes added to protect from inductive kickback.Vary Ra, Rb and Ct with the controls given and see the change of frequency, period and duty cycle.

Screenshot

Astable Multivibrator with 555

These are the formulae used by 555 and same is used in javascript without any change.

Monday, April 01, 2019

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.

Mass Spectrometry and Portable Microbe Detector

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.

Ideas of delabs - 2004- First posted in my blog Analytical Bionics.

Learn more about the Subject Basics

Saturday, February 02, 2019

Whence Input Hence Output

If Inputs are Distorted, The Outputs are Noisy.
Even if the Amplifier is Very Good.

If Raw Materials are of Poor Quality, The Finished Goods are Defective.
Even if the Process and Machinery is State Of The Art.

If the Specifications are incomplete, The Prototype will be rejected.
Even if the Design and Tools are Perfect.

Whence Input Hence Output - delabs

EE Design Library - Electronic Product Design Resource.

2002 - delabs Notes

Engineering the Technology Management

Sometimes even Management has to be Engineered to help it change its ways of thinking in a world that is fast changing. A Planet that is defined by the Consumer or Customer more strongly than any other factor.

Technologies should scale with Infrastructure. Buildings cannot stress the Foundations meant for. Traffic proportional to Road Width. Sync

Technology Management

Raw Materials - Components - Finished Products. The Entire Processing and Design Chain has to improve, if the final Product has to Shine.

Let us use more of our Brain than Brawn, Quality; Reliability & Safety will see a Dawn.

High Value Engineering

In Engineering High Value products are those that are a combination of Precision Mechanical + Electrical + Analog + Embedded Microcontroller.

Study and Learn ?? Examine and Experiment >> Analyze and Establish [o] Realize !!

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delabs Notes - 2002

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