[sdiy] more power questions

[Christian Sandgaard Thuesen]

 The extra voltages probably come when you try to rectifie the 12 volts AC.
Time for an example: A guy from Denmark decides to rectifie the 220V outlet
in the wall, now what happens? 220V AC is measured with a RMS meter, that
means that it measures the actual voltage, NOT the peak value. The peak
value is 220 * 1,4 = 308, if you run trough a rectifier you only get the
peak value and not the peak-peak value wich is actually twice as large.
After the rectifier you run it trough some electrolyts wich ought to
"straighten" the AC, idealy they will charge until the peak value (308V) and
never discharge, well not in this world they actually discharges a little
bit, seen as the "bumps", the bigger load the bigger bumps the bigger lyts
the smaller bumps.
 If you dosn't connect the voltage regulator correctly you will probably
also get some weird voltages too. I've seen datasheets with constuction
hints, very helpful if you need some advanced construction help.

 About the scope, try some of those buttons named trigger, if you use CH.1
make sure you trigger on channel 1 and that the trigger level is adjusted.
Maybe you could use CH.2 as a trigger, if you try to trigger on a DC it
might be hard to get a stable display. If ripple is what you want to see
(the bumps) try this: attach the probe the right place, set CH.1 to AC
coupling and trigger to CH.1 also in AC coupling, now turn the amplitude and
time division until you see those bumps. CH.1 position should be set at the
lower part of the display. Any qustions about scopes I am sure I can answer
them.
 Christian, the kid from Denmark.