8.1 - Low Voltage DC Power Supply Flashcards
Enclosure material?
Acrylonitrite Butadiene Styrene (ABS)
Enclosure material qualities?
Tough Impact resistant Good electrical insulator Inexpensive Malleable
Enclose purpose?
Protects components
Lowers risk of electric shock if touched when ‘live’
Transformer Core material?
Laminated steel strips (stamped from thin sheets)
Transformer Core material qualities?
Excellent ferromagnetic properties (strong magnet)
Transformer Windings material?
Enamelled copper wire (drawn out until a wire of the desired length is achieved, given thin enamel coating for insultation)
Transformer Windings material qualities?
Low resistance
Non-magnetic
Malleable
Transformer Windings purpose?
Turns a higher voltage (mains 230V) to smaller voltage for electrical device usage
More primary windings than secondary, voltage drops
Power Lead material?
Copper wire with multiple strands (flexible), with plastic insulating coating
Power Lead material qualities?
Excellent conductor
Printed Circuit Board material?
Glass-fibre reinforced plastic (composite material), given etched copper laminating coating to provide required coating track pattern (links component leads and pins)
Printed Circuit Board material qualities?
Strong
Good electrical insulator
Heat Dissipator (‘heat sink’) material?
Aluminium Alloy, shaped via extrusion
What is extrusion?
Hot alloy forced under pressure into a shape with a continuous cross-section, eg. heat sink
Heat Dissipator (‘heat sink’) material qualities?
Good heat conductor (cools circuit quicker)
Lightweight
Heat Dissipator (‘heat sink’) purpose?
Conducts heat away from an integrate circuit voltage regulator, convects it into surrounding space
Semiconductor material?
Silicon
Gallium Arsenide
Semiconductor material qualities?
Provide neither good nor bad electrical insulation, depends on amount and polarity of supplied voltage
Semiconductor devices?
4 Rectifier diodes
LED
Integrated circuit voltage regulator
Retaining Screws material?
Steel with black oxide finish
Retaining Screws material qualities?
Strong, forms own threads when inserted into soft plastic case pillars
Material selection criteria?
Availability (silver better than copper, but rarer)
Forms (need an Ali bar, only get blocks)
Cost
Properties (eg. strength, conductivity, heat resistance)
Manufacturing capability (can it be pressed, rolled, bent)
Environmental capabilities (eg. high temps, damp)
