delabs Circuits

Tuesday, June 10, 2014

Electronic Product Production.

a. PCB Assembly.

First Inspect PCB for hairline shorts and cuts and also traces of unwanted copper in the edges and repair them. Also Check if all Drill holes & Slots are proper size and PCB is Fitting in its Place properly, This is because Drilling and Filing should not be done after assembly as it causes serious reliability problems.

Second populate all the resistors, Jumpers, Diodes and Ceramic Capacitors these are tough components. Then Insert all Transistors, LEDs, Displays, Electrolytic Capacitors and IC s (Bases), Here care should be taken not to overheat any component as it may damage them. Lastly Solder Connectors, Relays, Coils and Transformers which may require a high wattage Iron, and Mechanical Reinforcements.

Electronic Product Production - delabs Technologies

b. Precautions during Production.
  • Observe Polarity for Diodes, El-caps, Connectors, etc.
  • Make sure of Pin 1 for IC s, Regulators, Transistors and Mosfets before insertion.
  • Avoid bases for ICs in production as these fail on use.
  • Make use of Electrostatic protection for CMOS devices.
  • When Cutting Leads use protective Goggles and do it in a separate place as the cut leads fly all over the place.
  • Use Iso Propyl Alcohol (IPA) as de-greasing agent on PCB.
  • Water & Detergent wash is very good but only if coils, Transformers, Relays are hermetically sealed- Impregnated.
Use a Lacquer-Varnish or RTV rubber coat on both sides of PCB including on the components to prevent corrosion and also it helps maintain accuracy-precision.

Lead is a kind of poison, use gloves or wash hands with soap after work is over. Flux, IPA, Thinner Fumes can cause respiratory health problems. Work in a ventilated area use Exhaust Fans and Open Windows. Dispose of Metal, Plastic and Chemical waste separately and well packed as these can contaminate the environment and also cause Injury.

Published online around - Nov 1999

Thursday, June 05, 2014

Amps-n-Volts Notes Corrected Improved

I have corrected, enhanced. moderated my design notes from my earlier Amps-n-Volts News Letter. My knowledge is limited to my experience, observation, perception, learning and beliefs, but i have to express my views freely. These posts are mirrored at Soldermans Basics.

Amps-n-Volts eMag

Near 2001 i started sharing my learning and experience in Electronics Engineering on Blogs and Newsletters. One of the Successful eMag and electronic email magazine ran for five years. I lost interest later in the email mag, and this magazine just morphed into a dozen or more Tech Blogs that run today. From the feedback i got, it has helped engineers and enthusiasts worldwide in Electronic Product Design.

Amps-n-Volts Notes Corrected Improved
  • Before you open a PC remove power, telephone modem and LAN cables else finger and screwdriver in wrong place can zap chips.
  • The products that survive the infant mortality time of say first six months will last quite long.
  • NTSC is like 320 x 240 pixels, which is TV, which is lower than your computer's 800 x 600.
  • When a microwave oven is turned on, a big spike is caused in the power line due to heavy inrush current on start up, Even pumps and motors cause such short time surges. This causes tripping of electrical protection circuits.
  • When a tree branch falls on the high voltage overhead electrical lines, they spark violently and supply trips.
  • Big or tall trucks go in small roads they may snap all low level cable or telephone wires on their way.
  • Do you need to turn on many equipments-machines all at once? do it one after an other sequentially or use a timer for delays. This is because at peak power demand time, turning on all can cause your fuse to blow or worse.
  • A battery that can be charged is best charged in CC constant current and CV constant voltage modes, that means both current and voltage have to be limited. When a battery is deep discharged many times it will age fast, and an empty battery will take huge currents so limit current. overcharging a battery will killit. After a voltage level is reached it should only trickle charge in mA and a battery has to be cut off on overload or before deep discharge
  • The Lead acid battery breathes a lot, so keep them in a well ventilated open space but rain proof. Use sealed maintenance free battery when possible, these are safer.
  • Teflon tape can be used to make leak proof pneumatic or hydraulic connections if junctions are leaking.
  • The current thru a 3mm or 5mm LED (light emitting diode) should not exceed 20mA, 15mA is quite good.
  • In a circuit swap all PNP and NPN , reverse all diodes and el-caps, reverse the supplies and input polarities, most of the circuit may still work like they did before.
  • A sharp bend in a PCB track is a huge inductance (say 1nH ) when it comes to RF. it may radiate or reflect, it may even act like an antenna and pick up RF from the SMPS, Motor or Cellphones nearby.
  • Persistence of vison around 16 frames a second (60mS) hence very fast events not seen .
Some of these points may be repeated and some not relevant in the present technical engineering scenario. As issues may have been set right, years back.

Amps-n-Volts Archive

Instrumentation Notes

Design Notes

Production Notes

Monday, June 02, 2014

Radio Electronics Magazine

Recently i found a collection of those mags at Archive.org ......

Radio Electronics Magazine at The Internet Archive

Radio-Electronics was an American electronics magazine that was published under various titles from 1929 to 2003.You can Read them all here ...

Radio Electronics Magazine at Archive.org

Hugo Gernsback, sometimes called The Father of Science Fiction, started it as Radio-Craft in July 1929. The title was changed to Radio-Electronics in October 1948 and again to Electronics Now in July 1992. In January 2000 it was merged with Gernsback's Popular Electronics to become Poptronics.

Radio Electronics Magazine at SWTPC
Gernsback Publications ceased operations in December 2002 and the January 2003 issue was the last.

Over the years, Radio-Electronics featured audio, radio, television and computer technology. The most notable articles were the TV Typewriter (September 1973)[1] and the Mark-8 computer (July 1974). These two issues are considered milestones in the home computer revolution.

Radio Electronics Magazine at SWTPC

Radio-Electronics was aimed at electronics' professionals such as radio and TV repairmen. And they were men, the tag line on the cover was "For Men with Ideas in Electronics".

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