Monday, January 12, 2015

Analog Op-Amp Circuits

Operational Amplifiers

With a few Op-Amps and a regulated Power supply, many Instrumentation and Process control equipment can be designed. The Human Brain understands Numbers, Quantity and it regulation very well ! On the right you can see a analog controller based on opamps and discrete devices. A Heater, Fan and Motor is regulated, controlled and timed for a process.

Analog Controller based on Opamps
Analog is about numbers, the circuits can be understood and designed mathematically or empirically. Designing and Building a True RMS Rectifier with Op-Amps, will help a designer digest many Op-Amp capabilities.

Read this to learn to use Op-Amps - Basic Semiconductor Circuits Manual

Analog Op-Amp Circuits

Things you ought to know about Op-Amps -

OpAmp part numbers from various semiconductor companies are designed for both General purpose and special applications. Some have to be cost-effective for consumer low-cost equipment, while others may be advanced in specs, closing in on an ideal Op-Amp.

Instrumentation opamps are used for accurate and low drift applications. These Op-Amps have stringent specifications and are used in the fields like Aerospace or Medical Electronics. A pre-amplifier for an FM Radio may need to be low-priced. Test Measurement needs Op-Amps which have near ideal specs in the area of measurement or application. CMOS low-power devices are used when designs are made for portable gadgets.
  • Outputs cannot be Loaded beyond the drive capacities, Note Resistors and Output Load.
  • Inputs draw a small bias current and will load the signal sources, compensate design.
  • Op-Ams AF-RF or Switching performance study with Slew rate and Bandwidth.
  • Power consumption of some Op-Amps are more and some very less, choose wisely.
  • Look for Standard Pin-Outs, Price, Popularity and study Abs. Max, AC and DC Specs.
  • Use Packages with multiple Op-Amps like LM324 to save board space and assembly time.
  • Op-Amps and its 1% MFR resistors should have a separate supply and far from hot parts.
  • Ultra Low Offset Voltage is required, when you wish to amplify a DC level of say 500uV.
  • Guard rings to be used for High impedance inputs and EMI-RFI Shielding for AF Amplifiers.
  • Glass epoxy PCB, clean surface, Pins and Tracks protected from Moisture and Chemicals.
  • Avoid Ground Loops, Have regulated Low ripple Power supplies. Dynamic Isolation.
delabs Technologies

Saturday, January 10, 2015

Drawing Tools for Electronic Schematics in Android

Here are some Circuit Diagram Drawing Tools for Android Tablets, they may be still under development. It may be Interesting to explore and try out.

Schematic Demo is an easy-to-handle and comfortable CAD-software, developed for different kinds of diagrams.

Schematic Demo Dmitry Ustimov

Editing objects performed by interaction with a device touch screen. You can create and edit such graphic objects as: - Point, Line, Polyline, Bezier curve, Arc, Ellipse and Rectangle.

Schematic Demo Dmitry Ustimov

Electronic schematic drawing application for Android by Harry Konstas
palmDraft lite ElectronicsCAD

palmDraft lite ElectronicsCAD

This is a bitmap-based CAD, featuring a high definition, flick-panning, pinch-zoom-able working canvas optimized for finger and pen drawing. It's as easy to manipulate as a sheet of paper. The schematics file format is standard .PNG bitmap file format which can be easily exported and shared for printing.

MCU simulator for Android OS

The MCU simulator for Android OS runs Assembly language code similar to the 68705 MCU on a simulated on-screen prototype board. Great for embedded applications hobbyists, students, teachers or anyone who likes to experiment with electronic Micro-controller prototype boards. It's fun for learning assembly language too!

Ostermiller Basic and Scientific Calculator

Scientific Expression or Formula Calculations. Twenty Transaction Memory and Tape, Different bases like Decimal and Octal, Logic Math, Functions, Constants.

Ostermiller Basic and Scientific Calculator -



Ostermiller Calculator xml code

Deriving knowledge and inspiration from ostermiller.org. The GUI and Skin Modifications were done by me.

Screenshot

Scientific Calculator

Source Code - delabs-dapj - scientific-calculator

It has Brackets to build your own math equation. Scientific Functions like Trigonometric, Hyperbolic, Logarithmic.Memory (cookies), A Paper Trail or Tape for Equation and Result History.

Thursday, January 01, 2015

Instrumentation Amp - Op-Amp Designs

This is the best Instrumentation OpAmp, Great CMRR, ensure supply has no ripple and keep analog and digital grounds separate. Ri can be replaced with a trimpot and resistor to alter gain. Connect a preset ends to pins 1 and 8 and preset wiper to VCC for Offset Null when high gains are configured.

Instrumentation Amp - Op-Amp Designs

Instrumentation Amp - Op-Amp Designs

The Input zeners and diodes form a protective clamp for all voltages above VCC-VDD. If supply is changed to +12 -12 change zeners to 12V zeners. Use similar Zeners at output to protect Output from being zapped by over-voltages or high energy - voltage or frequency transients. Add plastic capacitors across Rf for damping AC operation or ripple. Also avoid floating inputs by providing a bias, till you connect it to a sensor; or you will see electrometer like effects.

Three OpAmp Instrumentation Amp xml code