I have a little power supply module, made in 1983, for a burglar alarm, but I've seen the same thing on other printed circuit boards:
One of the metal traces on the non-parts side of the PCB has, in place of the 1/10" and 1/16" wide traces used elsewhere on the board that go to their destinations as quickly as possible, using straight lines, a half inch of one trace is zig-zag, sort of.It's really not a zig-sag since all of the angles are right angles, and none from Z's. Here it is:
___ ___ ___ |___| |__| like this, except smaller segments, 2 or 3mm. Not
even in a critical spot, afaict. It's the lead from a resistor, it looks like, that comes from an AC 12v transformer connection, to one of the 4 diodes in a bridge rectifier setup.** The first inch of this trace is straight for an inch, with a right angle and straight for another half inch.
Why don't they just use a straight line for the rest also?
Thanks.
**(FWIW, the bridge is followed by a filter cap and I think a voltage limiting transistor with a heat sink)Meirman