Prototype Fabrication Sometimes a component can be defective, may not be what it is labeled or may be of a wrong value. In manufacturing 100% incoming inspection of components can catch these errors, Before Assembly of prototypes just test all passive and active components with a DMM and put all ICs in bases, then troubleshooting is easy. When you make your prototype check diode and el-cap polarity, check pin 1 of chips and connectors, resistor values, dry solder and loose contacts, hairline cuts or shorts, e-b-c etc. of Transistors, FETs and thyristors. Observe color code in wires. positive is red [Read More ....]
Jan 152009
Design Notes – Schematic and PCB – 04
Basic Electronics, Design
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Jan 152009
PCB Thermal Design Care for Analog Circuit Stability If you have a hot power chip near a DC analog circuit, the values will drift, take time to stabilize, this happens even if you use 1% MFR 100ppm. The impact is more if the heatsink is not used and vents and coolers are absent, So in a PCB keep distance between heating power circuits and sensitive analog circuits, some times PCB tracks will carry heat to the Analog area, Hence keep sensitive analog circuits as plugin modules. When you make a PCB try to orient all ICs in one direction, so [Read More ....]
Design Notes – Power Electronics – 03
Power Electronics
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Jan 142009
SMPS designs should have clear line or patch of isolation for product safety and long term reliability. If you use opto-couplers they need to have 5kV or better isolation and 10mm between pins. The Live circuitry and the output circuitry should not overlap on PCB, tracks should not stray to the opposite side, The Transformers can be split bobbin if possible. A 10 to 20 mm desert (means no tracks) running from end to end of PCB under Transformer and under optos etc., Even ground tracks and ground planes should not stray. The high voltage side must have layer to [Read More ....]
Design Notes – Power Electronics – 02
Power Electronics
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Jan 142009
Power Supplies and SMPS, Transformers, Drive circuits for Motors, Heaters and Solenoids are all Power Electronics. Thyristors, Mosfets and High Power Transistors are important components used in these circuits. Foldback circuits in the form of constant current or voltage can protect a Power Circuit from overload. eg. Charger. Air gap in inductor core prevents saturation of the Magnetics, it must be made like that when required. eg. Choke. High power equipment should have a soft start, so that fuses dont blow on start, inrush can cause damage to parts. Caps can be put in series to double voltage withstand capability, [Read More ....]
Production Notes – Electrical – 02
Electrical, Power Electronics
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Jan 142009
All Electronic Products have interfaces to external electrical circuits. The power supply is also derived using converters or power supplies. Motors, Heaters and Transformers are examples of components in the electric power circuits. 12V lead acid batteries should be charged with a constant current CC and constant voltage charger the CV being 13.6V. Deep discharge and over charging will reduce the cycles. Lead acid batteries need a monthly distilled water update to ensure long life, sealed lead acid dont need attention. Keep lead acid batteries in well ventilated area due to acid fumes. Electric Shock can kill hence take great [Read More ....]
Jan 132009
Production, especially prototype testing and Pilot Production exposes lot of engineering and serviceability issues. When you mass produce, it is more streamlined, yet the scope for improvement never ends. The process should always be open to feedback and improvements. The tracks or components on a PCB should not be near the mounting holes, the tracks may form electrical connections with the cabinet earth if they touch the pillar, washer or nut-bolt. When you tighten the screws-nuts-bolt, limit torque by feeling or with torque limit screwdrivers, or thread will slip or PCB-Cabinet break, or CRT-Glass-Plastic will crack-shatter. After assembly and testing [Read More ....]
Jan 062009
Here are two pages from an old OK Industries catalog, now part of Jonard Industries. They have wire wrapping systems, which help build test systems, custom solutions easily. They have many Tools which improve productivity for the Electronics Manufacturing Industries. “Jonard Industries Corp is a World Class Manufacturer of Precision Hand Tools for the Telecom, Computer, Military and Electronic Industries.” Test Instruments bench rack from OK Industries From Electronic Catalogs This is a Mini Electric Drill of OK Industries From Electronic Catalogs
RTD 3-W Mains Power 4-20 mA Transmitter
Process Control
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Jan 052009
This is the Photo of a RTD 3-W Mains Powered Temperature 4-20mA Transmitter. The Circuits and PCB are here RTD PT100 Transmitter and Multiplexer. From Soldermans Basic Electronics Now with new Technologies like Zigbee and Modbus, We can classify Transmitters as shown below. The Measured Parameter Temperature, Flow or Events Has to reach an Intelligent Data Storage and Analysis System. It may just be an Human Operator who jots the data on a Notepad and Turns a Few Dials based on his Experience or an embedded controller. It could even be a Computer Network or a Web Application used by [Read More ....]
