Electronics 101 Info

Anyone have any good resources on electronic basics, specifically geared toward the builder?

E.G. I am building a phono pre and don't know how to hook up a power switch. Whats the different tabs on the back mean, I own switches with 3 tabs and 6 tabs, but dont know which are used for which application.

I recently trouble shot the female end of a three prong power cord, but could have saved myself a bunch of time if I had a reference website / book.

I am not necessarily looking for specific answers to the above questions, but if anyone has taught themselves, how did you learn?

I've dug around DIY audio, but that place isn't the most organized. DO i just need to spend more time there?

 

ESP has some really excellent articles on the basics, including grounding/earthing.

http://sound.westhost.com/articles.htm

Morgan Jones and Douglas Self are great references, but focus more on design principles and fundamentals than on actually making things work.

 

In addition to ESP (which should have the answers to your specific question in the PSU wiring guide), a lot can be learned from browsing build picture threads on HF and other forums. While these picture threads might not be the best place to get technical information, they are very useful for getting wiring and enclosure ideas. For example, some people like to use an AC power entry module with an integrated switch instead of a separate switch and power receptacle. Some people solder wires directly to the tabs; others use crimp terminals. Some wire everything directly, others use terminal blocks to keep things more flexible.

It is also useful to browse Mouser and Digikey to figure out what things are actually called and how to use them. The technical documents and datasheets are usually quite detailed. Browsing these websites will also give you an idea of the sheer number of possibilities when it comes to electronic components. For example, if you wanted to source a new power switch, there are pushbutton switches, toggle switches, rocker switches, rotary switches, etc, each with many options for termination style, mounting style, number of contacts, switch function, etc.

 

Here is some general info related to power in North America, from the perspective of an electrician... Electronics circuits also apply.

With regards to power, 120V power has the hot which is switched and sometimes on a brass screw; the neutral which should not normally be switched (it's on the larger prong on polarized plugs); and finally the ground wire which normally goes to green coloured screws and should never be switched.

The purpose of the bonding wire (which most people call the ground) is to ensure all metal parts of equipment are connected solidly to the ground. This is simply for safety, in case a wire accidentally touches the case. It can also be used as a reference point in power circuits, but current shouldn't normally flow through the ground, ever.

The neutral wire is grounded back at the panel, and also at the source which feeds the panel (eg. A transformer on a pole). The neutral is a dedicated path for current back to the source, and although it's grounded, it can cause shocks. Also, if the neutral is opened, it could be at the same potential as the hot wire. One of the reasons why you put the switch in front of your load, and don't switch the neutral.

Switches should be fairly straightforward... They should be rated in volts and amps. Use a multimeter to check continuity between pins if you're unsure.

The throw of the switch is the number of positions (eg. On/off switch is a single throw...). The poles of the switch refer to the number of lines you're switching (eg. One pole would be for a 120V switch with only one hot wire).

A regular light switch in your house would be a SPST (single pole single throw). All it does is open or close the hot wire feeding the load (eg. A light). A 240V breaker feeding two lines to a clothes dryer would be a DPST since it disconnects two hot wires.

The power feeding most houses and also used in AC electronics is single phase. The transformer winding is 240V from end to end, and we create a neutral point in the middle which is grounded. From either end to the neutral will be 120V. (This is also called an Edison three wire circuit, since as all North Americans know, Edison invented anything and everything to do with electrical /sarcasm).

 

Thanks @Mikoss - great info here

I've recently found the DIY Audio Circuits page and found the tutorials somewhat useful as well - http://www.diyaudiocircuits.com/tutorials/