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Where To Start In DIY Electronics?
pyrosine writes "I've been thinking about this for a while and have no idea where to start. I have little or no previous experience in electronics — just what is covered in GCSE physics (wiring a plug and resistors — not much, I know). The majority of my interest lies in the wireless communication side of the field — i.e. ham radios and CB — but I am also interested in how many things work, one example being speakers, simply to better understand it. I would preferably like to start with some form of practical guide rather than learning the theory first, but where I would find such a walkthrough eludes me."
I have had plenty of times shocking myself when playing with what I thought were safe devices. Here are a couple that caught me off guard:
1: Capacitors. Even though you are unplugged and powered off, a capacitor can be holding a surprise for you. The one that I learned on was built into a camera flash: So even though the device was powered by a couple of AA batteries (removed), sitting in wait was a capacitor with several thousand volts. I recall getting up off the floor wondering WTF just happened.
2: Relays. These devices use an electromagnet to move a metal reed, which closes (or opens) the connection for another circuit. Be aware that when a magnetic field collapses, electricty is 'made'. So even though I was driving the electromagnet with 9v, the shock I got when the field collapsed was likely several hundred volts. This wouldn't have been quite the problem, if I weren't using the relay to drive the relay (the switched circuit was closed in the unpowered position, and open when powered) - which creates an oscillator. This means that I shocked myself quite a few times before I could get the breadboard off of my hand.