ELECTRONIC COMPONENTS - LEARN ELECTRONICS

Capacitors continued. 

I intend to conclude with capacitors in this blog but also need to finish the general topic of electronics started in the previous blog, so here goes.

Fuses may be found in virtually all electronic equipment ranging from as low as a few milli-amps to hundreds of amps. The purpose of a fuse is to stop further destruction to an electronic device when some component had failed which caused the fuse to blow, limiting destruction to the device. Fuses mostly encountered in electronics are of the glass type though the SMD ceramic fuse is becoming popular. Earth leakage circuit breakers are used in larger equipment. Virtually every TV, video machine, CD Player, digital camera, photographic flash unit, ham radio, camcorder, Hi Fi, Inverter, Security Alarm, Power supply, Electric fences, Microwave oven, Computer, etc etc... has a fuse or fuses inside. Often positioned in a snap-in holder soldered on a PCB. Fuses are probably the most underrated electronic component but plays a vital role in human safety, so please don't go bypass them in any repair.

Wire is a conductor coated by an insulator. Wire can be found in various thicknesses inside equipment and the measure for wire is describe as standard wire gauge. Wire is predominantly made of copper since its a good conductor of electricity, sometimes its made of aluminum. Like that used for earthing aerials. Wires do have some resistance but of no concern at the moment. Wires are normally selected for its current carrying capabilities thus the thicker the conductor the more current it can deliver and the inverse is true for thinner wire. In electric fences, uninsulated stainless steel wire is used with insulated wire for underground cabling.

PCBs (printed circuit boards) are the forms or substrate used to manufacture electronic equipment from a meager "power supply" to a "computer" and forms the basis of most electronic gadgets. It essentially provides a connection capability between components predetermined by design. In the absence of a PCB, we would be compelled to connect components together with short lengths of wire which would be very cumbersome and messy and a nightmare to make sense of. PCBs are produced as a photo-litho process, etched in ferric chloride (or similar solvent) and drilled. Often different size holes are drilled dependent on the type or size of component it needs to support. PCBs come as single sided, double sided and multilayer boards application dependent. PCBs with edge connectors are commonly gold plated.

Switches are the devices we use to power electronic equipment on and off. Switches comes in various sizes and shapes, mostly with two contacts which are called SPST (single pole single throw) switch, meaning that the switch only has one contact and when the switch is operated, it either opens or closes.  Then there is SPDT (single pole double throw) meaning 2 SPST in the same switch. For example, if it is used to switch mains, there is a pole for both Live and Neutral each switched separately but simultaneously. Then there are DPST (double pole single throw) and DPDT (double pole double throw) and an assortment of other switches to many to cover right now. Switches are used less today than before because most equipment today function on low power and soft switching, meaning a solid state device is used to power up the equipment, like in an alarm system. Reset switches are also popular and come in two flavours PTM (push to make) and PTB (push to break) often found on the front panels of computers.

Lead, tin, silver, gold, tungten, nichrome, copper, brass, aluminium and iron plate are just some of the metals used in electronics.

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