PCB layout

Thread Starter


Joined Apr 21, 2004
i found this on the net it says simple standards to follow for a pcb wiring.
my question is that this is for jumpers right? if ever i need to use them?
and wires can some1point to a website that has a chart of what wire i need to use for this certain amount of voltage/current
and what does MIL-STD-12D mean



Joined Apr 28, 2004
When you draw a PCB out on paper (or computer) the connection wires are supposed to be color coded as listed.

Mil-Std = Military Standard.

Thread Starter


Joined Apr 21, 2004
follow up question what is a filament on table 1-3
and the table below what conductor does it mean is it the traces?

thank u



Joined Nov 17, 2003
You'll probably find that MIL-STD-12D is an Engineering Standard that details resistor colour codes used in practical engineering applicaions. It will also detail any deviations from standard practice.

It sounds pretty pointless, but there are engineering standards for everything you can think of!


Joined Apr 20, 2004

I think you ran into a very old circuit. The color codes date back to at least the 1960's. I am pretty certain, as the filaments you are asking about are the cathode heaters for a vacuum tube circuit. The slate color code was standard for the 6.3 VAC heater supply windings. I believe there would also be two reds and a red/yellow for the B+ supply, about 200-300 volts.

The second table is spacing for circuit board traces carrying the stated voltages. It's probably valid for FR4 glass substrate pcb's. If you're going to use phenolic, consider increasing spacing by about 25% for voltages over 100.