Miscellaneous electronics, parts, components, etc. 

This section is for miscellaneous electronic items, that span all power systems, or do not fit anywhere else.

Getting components/parts:

I try to use circuits that have parts carried by Radio Shack, but they are slowly phasing out parts, and when you used to be able to buy a resistors in different values, often all you can get is an "assortment".

Internet ordering is probably where you will need to go, try DigiKey or Mouser or All Electronics

Reed switches:

I recently found what seems to be identical to the reed switches that come with the QSI boards, these are nice general purpose reed switches. Look up part number 59025-010-nd on the Digikey site

Some commonly requested/misunderstood items/circuits

Full wave bridge rectifier:

Here is a picture of the most requested item, a full wave bridge. Normally, it is used to convert AC into DC, but you can feed it DC that changes in polarity to get DC on the output that is of known polarity.You can buy these from Radio shack made up, they are all in one unit with 4 leads. The leads show + and - output, and two, the inputs have a "~" on them (Means AC input). The use that many people do not consider is taking DC of any polarity and outputting DC of a "known" polarity. 

Using a 3 terminal bicolor led where you have DC of "reversing polarity"