delabs Circuits

Showing posts with label Thermocouple-Amplifier. Show all posts
Showing posts with label Thermocouple-Amplifier. Show all posts

Sunday, October 19, 2014

Design of a Thermocouple Amplifier.

(summary) 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.


1) Reg diagram STC1000A :
Is the reference voltage REF used for cold temperature compensation ?
2) What is the function of q1 and q2 transistors ? Are they also BEL100N ?
3) What is the function of VR2 ?
4) What is the function of P2 , P1 ?
5) How can I calculate the voltage at the output IC2A?
6) Is is possible for you to send me a circuit explanantion which will help me to understand all the circuit operations ?

Design of a Thermocouple Amplifier.
The circuit stc1000a.pdf is here name is "temperature controller, j and k input, pdf"

From: TF

REF is pin no 13 in header of the connector CON1 of board STC1000A. The CON1 of STC1000A is plugged into CON1 of STC1000B main board. it goes to Stable Reference LM336 2.5 IC2 of STC1000B, the entire STC1000x series is a set. RT1 is for cold junction compensation, see how to build it in dact0006.pdf .

Q1 and Q2 are BC547 small signal NPN, The act like crude attenuators with the resistor networks. This circuit is to linearize the output, study other circuits in my page you will understand. When the analog voltage becomes a bit more than 1% off from a line the switch can be put on. You can even use things like CD4066 and other analog switches but it will increment the cost. IC2D is just a differential opamp circuit see theory.

This amp switches the transistors to linearize output at an area determined by VR2. P1 and P2 are for 'zero' cold junction and 'full scale' calibration, these are given in the theory section. IC2A is a buffer there is nothing to calculate, read the theory here you have to study many of the links i post and also many other links to other sites, that will help you more.

delabs

Read the Full Page - Design of a Thermocouple Amplifier Full

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