delabs Circuits

Thursday, January 15, 2009

Design Notes - Analog and Opamps - 01

LM335 and LM336 -

LM335 is a temp sensor, LM335 . use it for temp for CJC. Temperature Sensors - RTDs and Thermocouples in  Temperature Measurement.

LM336-2.5 is an voltage Reference. precision 2.5V shunt regulator diodes, Applied as a precision 2.5V low voltage reference for digital voltmeters, power supplies or in opamp signal conditioning.

Current Loop -

4-20 ma will drive DC drives, motors and steam valves. It is a current loop, for long distance transmission, current loop is not prone to noise and hum, EMI RFI. As it is a small power transmission no loss of data, also many equipments can be in one data loop. A single transmitter with 4-20mA out can drive a strip-chart recorder, motor, controller and SCADA input. all in a series loop. Current loop is like 4-20 mA

Opamp Notes and Types
  • TL062, LF353, TL072, fet input. 1 tera ohm input imp.
  • OP07 higher price, 1 giga ohm. 75uV offset.
  • LF353 pin to pin replacement of TL062-72 and 82.
  • LM358 works on single supply too, low price, inp imp 1 meg.
  • LM324 Quad, works of batteries well.
  • All work best with dual +/- 5 V or more. LM7805 -LM 7905.
Analog Electronics: Basic Circuits of Operational Amplifiers

Examine the operation of the following circuits of operational amplifiers: inverting amplifier, summing amplifier, difference amplifier, differentiator, and integrator.

Remembering Bob Pease

Remembering Bob Pease

Points to Note -
  • Analog ground (opamps), digital ground (CMOS) and power ground (relays and LED) should be separate, (linked at root)
  • Glass epoxy PCB have high insulation resistance, above 10 tera ohms, and are not hygroscopic which means they do not drink water vapor, this makes them very suitable for precision instrumentation and sensitive circuits.
  • When you measure DC levels in 16bit accuracy or more you need resistors which have temp. coeff. of 10ppm, or you may have to put the entire circuit in a stable 45 deg oven. Thermoelectric effects, EMI, RFI, pA Leakage currents, ground loops, contact resistance all can make the readings drift and unusable.
  • High impedance points of circuit like 500 kilo ohm and above can pick up AC noise and DC leakage currents. this will affect the performance of circuit, so for DC you have to put a guard ring of the signal ground around that point in PCB. For RF you have to shield with things related to iron and mu metal, for low signals even a copper shield will do.
  • Percentage and ppm: when percentage becomes like 0.001% it is difficult to manage, so we use ppm-parts per million.5% means 5 parts in 100 parts. 23 ppm means 23 parts per million parts. 0.001% - shift the dp-decimal point four places to right it is 10ppm. 0.01% is 100ppm which is the variation of value of mfr resistors on temperature change.
Learn this at my Industrial Process Control Circuits

Contents

Basic Electronics
Basics of Electronics
Product Production
Work Discipline
Testing Points
Learning Electronics
Electronics Theory

Production Notes
Prototype Fabrication
Electrical Circuits
Electromechanical


Library
Scots Guide Electronics
Engineering - Wikibooks
Design Lab - Jim Svoboda
DC Circuits UOG
Socratic Electronics
Blobz Guide Electric Circuits


Product Design
Product Development
Constant Current Source
Good Voltage Regulators
Insulation Resistance
Digital Insulation Tester
DN Schematic PCB 04
DN Product Design 07


Hobby Circuits
VU Meter Circuits
LED brightness control
555 Incredible Chip
Process Control
liquid level measurement
Thermocouples and RTD
Design ADC Interface uC
Thermocouple Amplifier
IA Instrumentation 02
Temperature on DMM
Optical Proximity Switch
Analog Mux - Data Acquisition


Test Measurement
Instrumentation Automation
NI Test and Measurement
DMM Digital Multi Meter
Oscilloscope in T&M
IA Automation 01
Build Instruments
Tektronix T&M Equipment
Educators Corner – Agilent


Power Electronics
UPS Background
Transformer Connections
DN Power Electronics 03
DN Power Electronics 02
Half Bridge Convertor SG3525


Embedded
Interfacing Microcontrollers
Embedded Process Control
80C31 8052 Microcontroller
Microprocessors and uC
Embedded Systems Design

Components
Good Voltage Regulators
Relays and Contactors
Potentiometers Trimpots
Prototype Boards Types
Types of Capacitors
Types of Switches
Resistors How they Work
Coils Transformers SMPS
Mains Transformers Types
DN Components Selection 05

Tutor Gadgets
Count-Up Timer
Digital Logic Gates
Electronics Tutors

History
Teaching Instruments
Charles Proteus Steinmetz
Muntzing a Circuit Design
Teralab Electronics projects
Historical Instruments


Tables, Charts, Videos
Binary and Hex
Resistor Color Code
Ohms Law
Giga, Tera, Pico, Nano
High Resistance Materials

Analog
School - Analog Design
DN Analog Basics 06
DN Op-Amps 01
TI Semiconductors