Showing posts with label Analog-Circuits. Show all posts
Showing posts with label Analog-Circuits. Show all posts

Tuesday, November 17, 2015

Learn Analog Op-Amps Circuit Design

delabs Op-Amp Circuits (painstakingly) updated, The basic circuits and notes. some related resources in those pages too. An interactive tutor is also available.


Learn Analog Op-Amps Circuit Design
This is just a formatted-edited email thread exported from Eudora from my mailbox using the content concentrator. The circuit above was made by TF a student, This thread for circuit above has been put online to share information. The part under "From: delabs" are my writing. there may be some mistakes and broken links.

Design of a Thermocouple Amplifier.

This is in continuation of the thread called "Design of a Thermocouple Amplifier" doc00023.html which is in the same section .

Design of a ADC Interface for Microcontroller.

I need a few tips from you on Analog design in general: I have seen that a lot of ADCs have a separate AGND and DGND, but they are shorted at the chip. I believe this is required to keep the noisy digital return paths sperate from the analog return paths.

Analog Ground and Digital Ground

Sunday, June 28, 2015

The Spice in Analog Design

Analog Designers created Spice, Analog Design Professionals are adding their experience in many commercial and free spice EDA tools. When you are creating a new demanding design, a working solution is achieved by combining workbench and simulation work.

The Spice in Analog Design

Lab Test Bench and Breadboard testing needs to be done along with analog simulation. Power and mixed signal design too, needs to be verified on board. This is more true for a new design lab or new engineers. Experienced designers will not make many mistakes as design blocks would be in their collections or in their knowledge base. It is this knowledge that can build the simulator itself, this makes the simulator as skilled as the designer but also limited to his or that firm's experience. In a full digital design, simulation does a more complete Virtual Test bench role.

A simulation tool can help you test the blocks and helps catch some design and concept errors. When you build a live breadboard prototype, some real issues facing your design can emerge.

Spice is a analog design aid and helps mixed design circuit simulation, See the Spice homepage.

SPICE (Simulation Program with Integrated Circuit Emphasis) is a general purpose analog electronic circuit simulator. It is a powerful program that is used in IC and board-level design to check the integrity of circuit designs and to predict circuit behavior. - Wikipedia

Spice Resources

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.
Anantha Narayan

Wednesday, August 13, 2014

Analog Electronic Circuit Design

The very first designs that came about were analog designs, a Vacuum Tube amplifier is an example. Analog is the representation of data or physical parameter in an accurate and precise decimal number like + 72.182 mV. The greater the resolution required, the more demanding is the design for achieving high accuracy and low drift. Digital circuits have only two voltage levels, high and low, the third state of floating, Hi-Z or high impedance is only for multiplexing or sharing a bus. This is done so that devices dont drive into each other and it is also used in external port drivers.

As an analogy, see the conventional water tap as an analog control, an electric light ON-OFF switch as a digital control.

Bob Pease - Analog Guru

Among the semiconductor products Bob designed are temperature-voltage frequency converters used in groundbreaking medical research expeditions to Mt. Everest in the 1980s. He also designed a seismic pre-amplifier chip used to measure lunar ground tremors in the US Apollo moon landing missions. Among his more memorable designs are the LM331 voltage to frequency converter and the LM337 adjustable voltage regulator. - Remembering Bob Pease

Bob Pease - Analog Guru

Even in digital, going from a low level say 0V to a high level say 5V is not instantaneous, the side of the square wave or the rising edge is not as straight as it looks. On zooming only the edge, you see that it is also an analog phenomena. The 'square wave' itself appears to be a summation of many sine waves, 'harmonics'. This is because nature is analog, the sine wave is analog, the movements of the planets or even the spin of electrons in an atom too.

After the handheld Abacus calculator (low-power, durable, bio-degradable), Mechanical and electro-mechanical computers were made and studied, The very first electronic computers were Analog Computers using an opamp as a building block.

Then came huge Digital Computers, Later LSI and other Microelectronic Innovations have precipitated handheld computers.

Have a look at Op Amp Applications Handbook

The Rising edge of the square wave depends on the Transient Response of the devices, the slew rate and bandwidth too. Fast Op-Amps are required for many applications, in switching and also AC amplification. Beyond that, study goes into Power Electronics and RF-Microwave which are specialized extensions of Analog. Similarly study of Digital Circuits extends into Computers.

Analog Design and Circuits

Analog Circuits Instrumentation
Circuits in Above
Updated Aug-14
Anantha Narayan

Friday, April 09, 2010

Analog Op-Amp Tutors with Gadgets

I have made some Web Widgets, these are analog opamp tutors. Interactive Tutorial with Simulated Meters and Potentiometers, demonstrating how Operational Amplifier functions in different configurations.

Interactive Tutorials using Virtual Electronic Components 

Slide the Potentiometers just like you would operate a Sliding Control. Drag the Knob on Pot to increase or decrease the resistance. The Resistance is shown is blue letters and dynamically alters value as you slide the pot.

Analog Op-Amp Tutors with Gadgets

The mV Source is varied by just moving mouse pointer over the two buttons, no clicking. This reduces finger strain and also you have a long lasting mouse. The mV buttons are special, the variation picks up speed if you let the mouse pointer remain on the button. This is Ramp-up and Ramp-down. This enables you to set it faster with just two buttons.

Finally you have a DVM a Digital Volt Meter that just Displays the Voltage at any Point, this readout value has to be noted down.

Op-Amp Simulation using Javascript

If you wish to examine the code - Analog Tutorials Project Page

I am also attempting a Toy Scope or a waveform display.